生存保險費

Willem Koekkoek (1839-1885) was a Dutch painter.

本頁有以下小節

假設被保險人投保 \(n\)年生存保險(pure endowment),其契約規定,當被保險人於 \(n\)年後到期仍生存時,保險公司應給付生存保險金 \(1\)元,其現值為
\begin{equation}{\label{eq485}}\tag{1}
{}_{n}E_{x}=v^{n}\cdot {}_{n}p_{x}=v^{n}\cdot\frac{l_{x+n}}{l_{x}}
=\frac{v^{x+n}\cdot l_{x+n}}{v^{x}\cdot l_{x}}=\frac{D_{x+n}}{D_{x}}=a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\mbox{。}
\end{equation}
若 \(n\)年內身故時,將分別探討保險公司不退還及退還已繳之保險費。假設繳費期間為 \(q\)年,其中 \(q\leq n\)。

\begin{equation}{\label{a}}\tag{A}\mbox{}\end{equation}

不退還已繳之保險費.

若 \(n\)年內身故時,保險公司不退還已繳之保險費。各種不同類型之繳費方式之計算公式分述如下:

躉繳純保費.

躉繳純保費即為被保險人之生存保險金現值 \({}_{n}E_{x}\),其計算式為(\ref{eq485})式。假設保險公司於被保險人身 \(n\)年後到期仍生存時給付 \(\Lambda\)元生存保險金,則躉繳純保費應為 \(\Lambda\cdot {}_{n}E_{x}\)。

年繳純保費.

其年繳純保費以符號 \({\cal P}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}\)。依據收支平衡原則,可解得
\[{\cal P}_{x:n\!\rceil ,q}=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}}
=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:q\!\rceil}}
\mbox{ 及 }{\cal P}_{x:n\!\rceil}=\frac{{}_{n}E_{x}}{\ddot{a}_{x:n\!\rceil}}
=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:n\!\rceil}}\mbox{。}\]
假設 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金,則年繳純保費應為 \(\Lambda\cdot {\cal P}_{x:n\!\rceil ,q}\)或 \(\Lambda\cdot {\cal P}_{x:n\!\rceil}\)元

真實保險費.

其真實保險費以符號 \({\cal P}_{x:n\!\rceil ,q}^{(h)}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{(h)}\)。依據收支平衡原則,可得
\[{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}={}_{n}E_{x}\mbox{,}\mbox{。}\]
因此,依據基本型生存年金頁之(31)式,可解得其真實保險費為
\begin{align}
{\cal P}_{x:n\!\rceil ,q}^{(h)} & =\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (1-{}_{q}E_{x}\right )}\mbox{ (依據基本型生存年金頁之(31)式)}\label{eq483}\tag{2}\\
& =\frac{{\cal P}_{x:n\!\rceil ,q}\cdot\ddot{a}_{x:q\!\rceil}}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (1-{}_{q}E_{x}\right )}
=\frac{{\cal P}_{x:n\!\rceil ,q}}{1-\frac{h-1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (1-{}_{q}E_{x}\right )}\mbox{。}\nonumber
\end{align}
又可寫為
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{(h)} & ={\cal P}_{x:n\!\rceil ,q}+\frac{h-1}{2h}
\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot\left (1-{}_{q}E_{x}\right )\\
& ={\cal P}_{x:n\!\rceil ,q}+\frac{h-1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )\\
& ={\cal P}_{x:n\!\rceil ,q}+\frac{h-1}{2h}\cdot{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot
\left (1-\frac{a_{x:q\!\rceil}}{\ddot{a}_{x:q\!\rceil}}\right )\mbox{。}
\end{align*}
由上式可以明顯看出與年繳保費 \({\cal P}_{x:n\!\rceil ,q}\)比較將會產生
\[\frac{h-1}{2h}\cdot{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot\left (1-\frac{a_{x:q\!\rceil}}{\ddot{a}_{x:q\!\rceil}}\right )\]
之差額。另外,亦可得
\[{\cal P}_{x:n\!\rceil ,q}^{(h)}=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (1-{}_{q}E_{x}\right )}
=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:q\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )}\]

\[{\cal P}_{x:n\!\rceil}^{(h)}=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:n\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )}\mbox{。}\]
假設 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金,則真實保險費應為 \(\Lambda\cdot {\cal P}_{x:n\!\rceil ,q}^{(h)}\)或 \(\Lambda\cdot {\cal P}_{x:n\!\rceil}^{(h)}\)元。

年賦保險費.

假設每年分成 \(h\)期,其年賦保險費以符號 \(\mathfrak{P}_{x:n\!\rceil ,q}^{[h]}\)表示之,若 \(q=n\),則簡單表為 \(\mathfrak{P}_{x:n\!\rceil}^{[h]}\)。依據收支平衡原則,可得
\[{\cal P}_{x:n\!\rceil ,q}^{[h]}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}
={}_{n}E_{x}\cdot\left (1-\frac{h-1}{2h}\cdot{\cal P}_{x:n\!\rceil ,q}^{[h]}\right )\mbox{。}\]
因此可解得
\begin{equation}{\label{eq223}}\tag{3}
{\cal P}_{x:n\!\rceil ,q}^{[h]}=\frac{{\cal P}_{x:n\!\rceil ,q}^{(h)}}{1+\frac{h-1}{2h}\cdot {\cal P}_{x:n\!\rceil ,q}^{(h)}}\mbox{。}
\end{equation}
令 \(\zeta =\frac{h-1}{2h}\),根據(\ref{eq483})及(\ref{eq223})式,可得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{[h]} & =\frac{{\cal P}_{x:n\!\rceil ,q}^{(h)}}{1+\zeta\cdot {\cal P}_{x:n\!\rceil ,q}^{(h)}}
=\frac{\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )}}
{1+\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )+\zeta\cdot {}_{n}E_{x}}\\
& =\frac{{\cal P}_{x:n\!\rceil ,q}}{1-\zeta\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot\left (1-{}_{q}E_{x}-{}_{n}E_{x}\right )}\mbox{。}
\end{align*}
上式亦可寫成
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{[h]} & ={\cal P}_{x:n\!\rceil ,q}+\zeta\cdot{\cal P}_{x:n\!\rceil ,q}^{[h]}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot\left (1-{}_{q}E_{x}-{}_{n}E_{x}\right )\\
& ={\cal P}_{x:n\!\rceil ,q}+\zeta\cdot{\cal P}_{x:n\!\rceil ,q}^{[h]}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-a_{x:n\!\rceil}+a_{x:n-1\!\rceil}\right )\mbox{。}
\end{align*}
由上式可以明顯看出與年繳保費 \({\cal P}_{x:n\!\rceil ,q}\)比較將會產生
\[\frac{h-1}{2h}\cdot{\cal P}_{x:n\!\rceil ,q}^{(h)}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-a_{x:n\!\rceil}+a_{x:n-1\!\rceil}\right )\]
之差額。另外,亦可得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{[h]} & =\frac{{\cal P}_{x:n\!\rceil ,q}^{(h)}}{1+\frac{h-1}{2h}\cdot {\cal P}_{x:n\!\rceil ,q}^{(h)}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )+\zeta\cdot {}_{n}E_{x}}\\
& =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:q\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )
+\frac{h-1}{2h}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{[h]} & =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:n\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )
+\frac{h-1}{2h}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}\\
& =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\left (1-\frac{1}{h}\right )\cdot
a_{x:n\!\rceil}-\frac{h-1}{2h}\cdot a_{x:n-1\!\rceil}}\mbox{。}
\end{align*}
假設 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金,則年賦保險費應為 \(\Lambda\cdot {\cal P}_{x:n\!\rceil ,q}^{[h]}\)或 \(\Lambda\cdot {\cal P}_{x:n\!\rceil}^{[h]}\)元。

比例分攤保險費.

假設每年分成 \(h\)期,其比例分攤保險費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\{h\}}\)表示之,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\{h\}}\)。根據收支平衡原則,可得
\[{\cal P}_{x:n\!\rceil ,q}^{\{h\}}\cdot\ddot{a}_{x}^{(h)}={}_{n}E_{x}\cdot\left (
1+\frac{{\cal P}_{x:n\!\rceil ,q}^{\{h\}}}{2h}\right )\mbox{。}\]
因此可解得
\begin{equation}{\label{eq224}}\tag{4}
{\cal P}_{x:n\!\rceil ,q}^{\{h\}}=\frac{{\cal P}_{x:n\!\rceil ,q}^{(h)}}{1-\frac{1}{2h}\cdot {\cal P}_{x:n\!\rceil ,q}^{(h)}}
\end{equation}
令 \(\zeta =\frac{h-1}{2h}\),根據(\ref{eq483})及(\ref{eq224})式,可得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\{h\}} & =\frac{\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )}}
{1-\frac{1}{2h}\cdot\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\zeta\cdot\left (1-{}_{q}E_{x}\right )-\frac{1}{2h}\cdot {}_{n}E_{x}}\\
& =\frac{{\cal P}_{x:n\!\rceil ,q}}{1-\zeta\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot\left (1-{}_{q}E_{x}\right )-\frac{1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot {}_{n}E_{x}}\mbox{。}
\end{align*}
亦可寫成
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\{h\}} & ={\cal P}_{x:n\!\rceil ,q}+{\cal P}_{x:n\!\rceil ,q}^{\{h\}}\cdot
\left [\zeta\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (1-{}_{q}E_{x}\right )-\frac{1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}
\cdot {}_{n}E_{x}\right ]\\
& ={\cal P}_{x:n\!\rceil ,q}+{\cal P}_{x:n\!\rceil ,q}^{\{h\}}\cdot
\left [\frac{h-1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )
-\frac{1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )\right ]\\
& ={\cal P}_{x:n\!\rceil ,q}+{\cal P}_{x:n\!\rceil ,q}^{\{h\}}\cdot
\left [\frac{h-1}{2h}\cdot\left (1-\frac{a_{x:q\!\rceil}}{\ddot{a}_{x:q\!\rceil}}\right )
-\frac{1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )\right ]\mbox{。}
\end{align*}
由上式可以明顯看出與年繳保費 \({\cal P}_{x:n\!\rceil ,q}\)比較將會產生
\[{\cal P}_{x:n\!\rceil ,q}^{\{h\}}\cdot\left [\frac{h-1}{2h}\cdot\left (1-\frac{a_{x:q\!\rceil}}{\ddot{a}_{x:q\!\rceil}}\right )
-\frac{1}{2h}\cdot\frac{1}{\ddot{a}_{x:q\!\rceil}}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )\right ]\]
之差額。另外,亦可得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\{h\}} & =\frac{{\cal P}_{x:n\!\rceil ,q}^{(h)}}{1-\frac{1}{2h}
\cdot{\cal P}_{x:n\!\rceil ,q}^{(h)}}=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}
-\zeta\cdot\left (1-{}_{q}E_{x}\right )-\frac{1}{2h}\cdot {}_{n}E_{x}}\\
& =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:q\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )
-\frac{1}{2h}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\{h\}} & =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\ddot{a}_{x:n\!\rceil}-
\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )
-\frac{1}{2h}\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}\\
& =\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-2}{2h}\cdot
a_{x:n\!\rceil}+\frac{1}{2h}\cdot a_{x:n-1\!\rceil}}\mbox{。}
\end{align*}
假設 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金,則年賦保險費應為 \(\Lambda\cdot {\cal P}_{x:n\!\rceil ,q}^{\{h\}}\)或 \(\Lambda\cdot {\cal P}_{x:n\!\rceil}^{\{h\}}\)元。

連續保險費.

其保險費以符號 \(\bar{{\cal P}}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \(\bar{{\cal P}}_{x:n\!\rceil}\)。依據收支平衡原則,可解得
\[\bar{{\cal P}}_{x:n\!\rceil ,q}=\frac{{}_{n}E_{x}}{\bar{a}_{x:q\!\rceil}}
=\frac{{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{1}{2}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )}
=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\frac{1}{2}\cdot\left (\ddot{a}_{x:q\!\rceil}+a_{x:q\!\rceil}\right )}\]

\[\bar{{\cal P}}_{x:n\!\rceil}=\frac{a_{x:n\!\rceil}-a_{x:n-1\!\rceil}}{\frac{1}{2}\cdot
\left (\ddot{a}_{x:n\!\rceil}+a_{x:n\!\rceil}\right )}\mbox{。}\]
假設 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金,則真實保險費應為 \(\Lambda\cdot\bar{{\cal P}}_{x:n\!\rceil ,q}\)或元 \(\Lambda\cdot\bar{{\cal P}}_{x:n\!\rceil}\)。

\begin{equation}{\label{b}}\tag{B}\mbox{}\end{equation}

退還已繳之保險費.

若 \(n\)年內身故時,保險公司以不計息方式退還已繳之保險費。若 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金。則其各種不同類型之繳費方式之計算公式分別推導如下。

年繳純保費.

將依身故當年末退還已繳之保險費與身故即刻退還已繳之保險費分別討論。考慮身故當年末退還已繳之保險費,其年繳純保費以符號 \({\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \({\cal P}^{\Lambda}_{x:n\!\rceil}\)。
保險公司的支出狀況如下所述:

  • 若被保險人於第 \(1\)年內身故,則保險公司須於當年末退還 \({\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)
  • 若被保險人於第 \(2\)年內身故,則保險公司須於當年末退還 \(2\cdot{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)
  • 依此類推,若被保險人於第 \(n\)年內身故,則保險公司須於當年末退還 \(n\cdot{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)
  • 若 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金。

若被保險人於 \(n\)年內身故時,其保險費退還方式類似遞增型之 \(n\)年定期壽險,被保險人若於第 \(1\)年內身故,則保險公司需於當年末給付 \({\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)元,若於第 \(2\)年內身故,則保險公司需於當年末給付 \(2\cdot{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)元,依此類推,每年增加 \({\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)元至第 \(n\)年為止,以後不再給付。因此保險公司總支出現值為
\[{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\cdot (IA)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\mbox{。}\]
依據收支平衡原則,可得
\[{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\cdot\ddot{a}_{x:q\!\rceil}
={\cal P}^{\Lambda}_{x:n\!\rceil ,q}\cdot (IA)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\mbox{。}\]
因此可解得
\[{\cal P}^{\Lambda}_{x:n\!\rceil ,q}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\]

\[{\cal P}^{\Lambda}_{x:n\!\rceil}
=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:n\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故即刻退還已繳之保險費,其年繳純保費以符號 \({}^{*}{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \({}^{*}{\cal P}^{\Lambda}_{x:n\!\rceil}\)。因此可解得
\[{}^{*}{\cal P}^{\Lambda}_{x:n\!\rceil ,q}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{ 及 }{}^{*}{\cal P}^{\Lambda}_{x:n\!\rceil}
=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:n\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{。}\]

真實保險費.

將每年分成 \(h\)期,將依身故當年末退還已繳之保險費、身故當年期末退還已繳之保險費與身故即刻退還已繳之保險費分別討論。考慮身故當年末退還已繳之保險費,其真實保險費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda (h)}\)。依據收支平衡原則,可得
\begin{equation}{\label{eq481}}\tag{5}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}
={\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\cdot (IA)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\mbox{。}
\end{equation}
因此可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)} & =\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}-(IA)_{x:n\!\rceil}^{1}}
=\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (1-{}_{q}E_{x}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:q\!\rceil}+\frac{h-1}{2h}\cdot a_{x:q\!\rceil}-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\[{\cal P}_{x:n\!\rceil}^{\Lambda (h)}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-1}{2h}\cdot a_{x:n\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故即刻退還已繳之保險費,其年繳純保費以符號 \({}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\)表示,
若 \(q=n\),則簡單表為 \({}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda (h)}\)。依據收支平衡原則,可解得
\[{}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:q\!\rceil}+\frac{h-1}{2h}\cdot a_{x:q\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\]

\[{}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda (h)}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-1}{2h}\cdot a_{x:n\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故當期末退還已繳之保險費,其年繳純保費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda (hh)}\)。保險公司的支出狀況如下所述:

  • 若被保險人於第 \(1/h\)年內身故,則保險公司須於第 \(1/h\)年末退還 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}/h\)
  • 若被保險人於第 \(1/h\)至 \(2/h\)年內身故,則保險公司須於第 \(2/h\)年末退還 \(2\cdot{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}/h\)
  • 依此類推,若被保險人於第 \(t+\frac{s}{h}\)至 \(t+\frac{s+1}{h}\)年內身故,則保險公司須於 \(t+\frac{s+1}{h}\)年末退還 \(\left (t+\frac{s+1}{h}\right )\cdot{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\),其中 \(t=0,1,\cdots ,n-1\)及 \(s=0,1,\cdots ,h-1\)
  • 若 \(n\)年後仍然生存時,可得到保險公司給付 \(\Lambda\)元保險金。

若被保險人於 \(n\)年內身故時,其保險費退還方式類似每年遞增 \(h\)次之 \(n\)年定期壽險。因此保險公司總支出現值為
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\cdot (I^{(h)}A)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\mbox{。}\]
依據收支平衡原則,可得
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}
={\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\cdot (I^{(h)}A)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\mbox{。}\]
每年遞增數次之人壽保險金頁之(31)式,亦可得
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}={\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)}\cdot
\left ((IA)_{x:n\!\rceil}^{1}-\frac{h-1}{2h}\cdot A_{x:n\!\rceil}^{1}\right )+\Lambda\cdot {}_{n}E_{x}\mbox{。}\]
因此可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda (hh)} & =\frac{\Lambda\cdot {}_{n}E_{x}}
{\ddot{a}_{x:q\!\rceil}^{(h)}-(IA)_{x:n\!\rceil}^{1}+\frac{h-1}{2h}\cdot A_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:q\!\rceil}+\frac{h-1}{2h}\cdot a_{x:q\!\rceil}-(IA)_{x:n\!\rceil}^{1}+\frac{h-1}{2h}\cdot
\left (v\cdot\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )}\\
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\Lambda (hh)} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-1}{2h}\cdot a_{x:n\!\rceil}-(IA)_{x:n\!\rceil}^{1}+\frac{h-1}{2h}\cdot
\left (v\cdot\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )}\\
& = & \frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1+v\cdot (h-1)}{2h}\cdot\ddot{a}_{x:n\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\mbox{。}
\end{align*}

年賦保險費.

將每年分成 \(h\)期,將依身故當年末退還已繳之保險費、身故當年期末退還已繳之保險費與身故即刻退還已繳之保險費分別討論。考慮身故當年末退還已繳之保險費,其年賦保險費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\)表示之,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda [h]}\)。依據終身壽險保費頁之(23)式之推導論點,可得
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}
=\left ({\cal P}^{\Lambda [h]}_{x:n\!\rceil ,q}\cdot (IA)_{x:n\!\rceil}^{1}
+\Lambda\cdot {}_{n}E_{x}\right )\cdot\left (1-\frac{h-1}{2h}\cdot {\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\right )\mbox{。}\]
由(\ref{eq481})式,亦可得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]} & =\frac{1}{\ddot{a}_{x:q\!\rceil}^{(h)}}
\cdot\left ({\cal P}^{\Lambda [h]}_{x:n\!\rceil ,q}\cdot (IA)_{x:n\!\rceil}^{1}
+\Lambda\cdot {}_{n}E_{x}\right )\cdot\left (1-\frac{h-1}{2h}\cdot {\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\right )\\
& ={\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\cdot\left (1-\frac{h-1}{2h}\cdot
{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\right )\mbox{。}
\end{align*}
令 \(\zeta =\frac{h-1}{2h}\),可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]} & =\frac{{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}{1+\frac{h-1}{2h}
\cdot {\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}=\frac{{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}{1+\zeta
\cdot {\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}=\frac{\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}
-(IA)_{x:n\!\rceil}^{1}}}{1+\zeta\cdot\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}-(IA)_{x:n\!\rceil}^{1}}}\\
& =\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}
-(IA)_{x:n\!\rceil}^{1}+\zeta\cdot\Lambda\cdot{}_{n}E_{x}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\Lambda [h]} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:n\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
&  \frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}
+\frac{h-1}{2h}\cdot (1+\Lambda )\cdot a_{x:n\!\rceil}-\frac{h-1}{2h}\cdot\Lambda\cdot a_{x:n-1\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\mbox{。}
\end{align*}

考慮身故即刻退還已繳之保險費,其年繳純保費以符號 \({}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}\)表示,若 \(q=n\),則簡單表為 \({}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda [h]}\)。依據收支平衡原則,可解得
\[{}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda [h]}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(I\bar{A})_{x:n\!\rceil}^{1}}\]

\[{}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda [h]}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-1}{2h}\cdot (1+\Lambda )\cdot a_{x:n\!\rceil}
-\frac{h-1}{2h}\cdot\Lambda\cdot a_{x:n-1\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故當期末退還已繳之保險費,其年繳純保費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda [hh]}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda [hh]}\)。依據收支平衡原則,可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda [hh]} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(I^{(h)}A)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )
-\left ((IA)_{x:n\!\rceil}^{1}-\frac{h-1}{2h}\cdot A_{x:n\!\rceil}^{1}\right )}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-A_{x:n\!\rceil}^{1}\right )
+\frac{h-1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-v\cdot\ddot{a}_{x:n\!\rceil}+a_{x:n\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\Lambda [hh]} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:n\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}-v\cdot\ddot{a}_{x:n\!\rceil}
+a_{x:n\!\rceil}\right )+\frac{h-1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\frac{h+1+v\cdot (h-1)}{2h}\cdot\ddot{a}_{x:n\!\rceil}
+\frac{h-1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

比例分攤保險費.

將每年分成 \(h\)期,將依身故當年末退還已繳之保險費、身故當年期末退還已繳之保險費與身故即刻退還已繳之保險費分別討論。考慮身故當年末退還已繳之保險費,其年賦保險費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}\)表示之,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda \{h\}}\)。依據(\ref{eq255})式之推導論點,可得
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}\cdot\ddot{a}_{x:q\!\rceil}^{(h)}
=\left ({\cal P}^{\Lambda [h]}_{x:n\!\rceil ,q}\cdot (IA)_{x:n\!\rceil}^{1}+\Lambda\cdot {}_{n}E_{x}\right )\cdot
\left (1+\frac{{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}}{2h}\right )\mbox{,}\]
由(\ref{eq481})式,亦可得
\[{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}={\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}\cdot
\left (1+\frac{{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}}{2h}\right )\]
因此可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}} & =\frac{{\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}{1-\frac{1}{2h}
\cdot {\cal P}_{x:n\!\rceil ,q}^{\Lambda (h)}}=\frac{\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}
-(IA)_{x:n\!\rceil}^{1}}}{1-\frac{1}{2h}\cdot\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}
-(IA)_{x:n\!\rceil}^{1}}}=\frac{\Lambda\cdot{}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}^{(h)}
-(IA)_{x:n\!\rceil}^{1}-\frac{1}{2h}\cdot\Lambda\cdot{}_{n}E_{x}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\Lambda [h]} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:n\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}
+\frac{h-1-\Lambda}{2h}\cdot a_{x:n\!\rceil}+\frac{1}{2h}\cdot\Lambda\cdot a_{x:n-1\!\rceil}-(IA)_{x:n\!\rceil}^{1}}\mbox{。}
\end{align*}

考慮身故即刻退還已繳之保險費,其年繳純保費以符號 \({}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}\)表示,若 \(q=n\),則簡單表為 \({}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda \{h\}}\)。依據收支平衡原則,可解得
\[{}^{*}{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{h\}}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(I\bar{A})_{x:n\!\rceil}^{1}}\]

\[{}^{*}{\cal P}_{x:n\!\rceil}^{\Lambda \{h\}}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{h+1}{2h}\cdot\ddot{a}_{x:n\!\rceil}+\frac{h-1-\Lambda}{2h}\cdot a_{x:n\!\rceil}+\frac{1}{2h}\cdot\Lambda\cdot a_{x:n-1\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故當期末退還已繳之保險費,其年繳純保費以符號 \({\cal P}_{x:n\!\rceil ,q}^{\Lambda \{hh\}}\)表示,若 \(q=n\),則簡單表為 \({\cal P}_{x:n\!\rceil}^{\Lambda \{hh\}}\)。依據收支平衡原則,可解得
\begin{align*}
{\cal P}_{x:n\!\rceil ,q}^{\Lambda \{hh\}} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(I^{(h)}A)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )
-\left ((IA)_{x:n\!\rceil}^{1}-\frac{h-1}{2h}\cdot A_{x:n\!\rceil}^{1}\right )}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-A_{x:n\!\rceil}^{1}\right )
-\frac{1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\ddot{a}_{x:q\!\rceil}-\frac{h-1}{2h}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}-v\cdot\ddot{a}_{x:n\!\rceil}+a_{x:n\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot
\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\begin{align*}
{\cal P}_{x:n\!\rceil}^{\Lambda \{hh\}} & =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\ddot{a}_{x:n\!\rceil}-\frac{h-1}{2h}\cdot\left (\ddot{a}_{x:n\!\rceil}-a_{x:n\!\rceil}-v\cdot\ddot{a}_{x:n\!\rceil}
+a_{x:n\!\rceil}\right )-\frac{1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}{\frac{h+1+v\cdot (h-1)}{2h}\cdot\ddot{a}_{x:n\!\rceil}
-\frac{1}{2h}\cdot\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

連續保險費.

將依身故當年末退還已繳之保險費與身故即刻退還已繳之保險費分別討論。考慮身故當年末退還已繳之保險費,
其保險費以符號 \(\bar{{\cal P}}^{\Lambda}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \(\bar{{\cal P}}^{\Lambda}_{x:n\!\rceil}\)。
依據收支平衡原則,可解得
\begin{align*}
\bar{{\cal P}}^{\Lambda}_{x:n\!\rceil ,q} & =\frac{\Lambda\cdot {}_{n}E_{x}}{\bar{a}_{x:q\!\rceil}-(IA)_{x:n\!\rceil}^{1}}
=\frac{\Lambda\cdot {}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{1}{2}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{1}{2}\cdot\left (\ddot{a}_{x:q\!\rceil}+a_{x:q\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}
\end{align*}

\[\bar{{\cal P}}^{\Lambda}_{x:n\!\rceil}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{1}{2}\cdot\left (\ddot{a}_{x:n\!\rceil}+a_{x:n\!\rceil}\right )-(IA)_{x:n\!\rceil}^{1}}\mbox{。}\]

考慮身故即刻退還已繳之保險費,其保險費以符號 \({}^{*}\bar{\cal P}^{\Lambda}_{x:n\!\rceil ,q}\)表示,若 \(q=n\),則簡單表為 \({}^{*}\bar{\cal P}^{\Lambda}_{x:n\!\rceil}\)。依據收支平衡原則,可解得
\begin{align*}
{}^{*}\bar{\cal P}^{\Lambda}_{x:n\!\rceil ,q} & =\frac{\Lambda\cdot {}_{n}E_{x}}{\bar{a}_{x:q\!\rceil}-(I\bar{A})_{x:n\!\rceil}^{1}}
=\frac{\Lambda\cdot {}_{n}E_{x}}{\ddot{a}_{x:q\!\rceil}-\frac{1}{2}\cdot
\left (\ddot{a}_{x:q\!\rceil}-a_{x:q\!\rceil}\right )-(I\bar{A})_{x:n\!\rceil}^{1}}\\
& =\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{1}{2}\cdot\left (\ddot{a}_{x:q\!\rceil}+a_{x:q\!\rceil}\right )-(I\bar{A})_{x:n\!\rceil}^{1}}
\end{align*}

\[{}^{*}\bar{\cal P}^{\Lambda}_{x:n\!\rceil}=\frac{\Lambda\cdot\left (a_{x:n\!\rceil}-a_{x:n-1\!\rceil}\right )}
{\frac{1}{2}\cdot\left (\ddot{a}_{x:n\!\rceil}+a_{x:n\!\rceil}\right )-(I\bar{A})_{x:n\!\rceil}^{1}}\mbox{。}\]

 

 

 

Hsien-Chung Wu
Hsien-Chung Wu
文章: 183

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