例題4-2 計算 exp( - (z^2)/2 ) / (2* Pi ) 在[-3.5, -3.0]的定積分

'''
例題4-2 計算 exp( -  (z^2)/2 ) /  (2* Pi )  在[-3.5, -3.0]的定積分
'''
import math

def  f(x) :
    return  (math.exp( -0.5*x*x) ) / pow( ( 2* math.pi) , 0.5)

def computeT(a , b ,  n) :
    h = (b - a) / n
    T = 0.0
    for i in range (1 , n ):
        T += f(a + i * h)    #  //1 <= k <= n - 1
    return  (h *  0.5 * (  f(a) +  2 * T + f(b) )  )

n = 10       #//區間等分數
a = -3.5
b = -3.0      #//上下限

print("answer = {%10.6f}\n"  %( computeT(a, b, n) ) )

輸出畫面
======= RESTART: F:\2018-09勤益科大數值分析\數值分析\PYTHON\EX4-2-0.py ==========
answer = {  0.001119}

>>>

https://www.wolframalpha.com/input/?i=integrate++exp(+-+(x%5E2)%2F2+)+++%2F++(2*+Pi+)+%5E0.5

integrate  exp( - (x^2)/2 )   /  (2* Pi ) ^0.5