怎么用matab找到​对某个概率密度函数从​0开始积分对应积分结​果为0.5的积分上限​，

假设这个函数为f,用代码说明

[Walter Roberson]

Approximate translation:

How to use matab to find the upper limit of integration for a certain probability density function starting from 0, and the corresponding integral result is 0.5,

Assuming that this function is f, explain it with code

Answer 1

[Walter Roberson]

format long g

f = @(x) exp(x).^2 - sin(x);   %example function

x0 = 0.8;
UB = fsolve(@(ub) integral(f, 0, ub) - 0.5, x0) 

Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the value of the function tolerance, and
the problem appears regular as measured by the gradient.

UB = 
         0.381241879389454

%check
integral(f, 0, UB)

ans = 
         0.500000173020638

[Yucheng]

你好，我在使用fslove求解f-0.5=0的根的时候，发现x0的取值可能使方程找不到根，matlab给出下面的警告：最小步长大小已快达到 x = 7.99072e+21。可能具有奇异性，或者容差可能对于此问题太小。

请问怎么样让x0的取值不影响根的求解结果