積分計算器不會工作，當給定的公式給定超過1 x的公式

Question

所以我現在正在積分計算器，它工作得很好，儘管只要將y定義爲x ** 2 + x * 2 + 2停止工作。是什麼促使我的程序使用y = x ** 2 + 2而不是y = x ** 2 + x * 2 + 2？

import math as math 

x0 = 0                      
x1 = 0                      

def func(y, x):                    
    return eval(y) 

def func2(z, x):                    
    return eval(z) 

def func3(c, d):   
    a = 0.0                     
    for i in range(1, n+1):                 
     x0 = a + (i-1) * dx                  
     Ai = dx * (c + d)/ 2.               
     a = a + Ai                  
    return a 

y = str(raw_input("Function 1: "))              
z = str(raw_input("Function 2: "))           

a = float(input("Left boundary: "))              
b = float(input("Right boundary: "))              
dx = float(input("Trapezoid width: "))              

n = int((b - a)/dx)                

Area2 = func3(func(y, x0), func(y, x1))                    
Area3 = func3(func2(z, x0), func2(z, x1)) 

Area4 = Area2 - Area3 
if Area4 < 0: 
    Area4 = Area3 - Area2 

print "Area = ", Area4                 

Answer 1

import math as math 

x0 = 0                      
x1 = 0                 

def f(function, x): 
    function = eval(function) 
    return function 

def func3(b, a, func):   
    area = 0.0 
    dx = (b - a)/n             
    for i in range(1, n+1):                 
     x0 = a + (i-1) * dx 
     x1 = a + i*dx 
     Ai = dx * (f(func, x0) + f(func, x1))/ 2.               
     area = area + Ai                  
    return area 

y = str(input("Function 1: "))              
z = str(input("Function 2: "))           

a = float(input("Left boundary: "))              
b = float(input("Right boundary: "))              
n = int(input("Trapezoid width: "))              


Area2 = func3(b, a, y)                    
Area3 = func3(b, a, z) 

Area4 = Area2 - Area3 
if Area4 < 0: 
    Area4 = Area3 - Area2 

print "Area = ", Area4 

這是或多或少你想要做什麼？