圆周率逼近程序

Question

这个问题要求编写一个程序，使用forumla pi =4/1-4/3+4/5-4/7+…

我必须提示用户列中的术语数，并计算近似值。这就是我试过的程序

import math

def main():

     dummy = 4.0
     term = 0.0
     n = 0.0

     print("This program approximates the value of pi")
     n = eval(input("Enter the number of terms you want in the approximation: ")


     for i in range(1, n+1)
              term = 4/(2n+1)
              dummy = dummy + ((-1)**n) * term

     print("The approximation is ", dummy)
     print("The difference between pi and the approximation is ", math.sqrt((math.pi - dummy)**2))

但是，当我试图运行它时，我会得到错误消息“无效语法”，变量"term“将以红色高亮显示。

Answer 1

您忘记了这行末尾的冒号：

for i in range(1, n+1):
                      ^ missing

每当您在看起来正确的行上出现语法错误时，尝试在错误之前查看行，以确定是否正确。

您还忘记了这行末尾的)：

     n = eval(input("Enter the number of terms you want in the approximation: ")

Answer 2

缺少操作符*：

term = 4/(2n+1)

更改为

term = 4/(2*n+1)

Answer 3

你错过了":“在for语句的末尾：

for i in range(1, n+1):
          term = 4/(2*n+1)
          dummy = dummy + ((-1)**n) * term