From 2cdffb7b7c351d883939e9240239b95ae6a7deec Mon Sep 17 00:00:00 2001
From: LIU ZHANWEI <50036800+Zhanwei-Liu@users.noreply.github.com>
Date: Sun, 15 Sep 2024 23:37:54 +0800
Subject: [PATCH] Update Mathematical_notations.rst

---
 doc/source/Mathematical_notations.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/source/Mathematical_notations.rst b/doc/source/Mathematical_notations.rst
index 0a8b8ca..1de344c 100644
--- a/doc/source/Mathematical_notations.rst
+++ b/doc/source/Mathematical_notations.rst
@@ -497,13 +497,13 @@ The total present value can be calculated as follows:
 
   \text{total present value} &= \frac{B}{(1+r)^m} + \frac{B}{(1+r)^{m+1}} + \cdots + \frac{B}{(1+r)^{(m+k-1)}} \\
   \\
-  &= B(1+r)^{(1-m)}\frac{1-(1+r)^k}{r}
+  &= B(1+r)^{(1-m)}\frac{1-(1+r)^{-k}}{r}
 
 And we can calculate the variable factor as follows:
 
 .. math::
 
-  \text{factor}_{y}^{var} &= (1+r)^{1-m_y}\frac{1-(1+r)^{k_y}}{r} \\
+  \text{factor}_{y}^{var} &= (1+r)^{1-m_y}\frac{1-(1+r)^{-k_y}}{r} \\
   \\
   m_{y} &= y - y_\text{min} \\
   \\