Integration to infinity

[ljl22]

Can anyone help? I have to integrate between 0 and infinity for cos(x)/sqrt(x)

#include<stdio.h>
#include<math.h>

#define PRECISION 0.001

int main()
{
float x;
float y;
float z;
float a;
float h;

printf("Enter trapezium height 'h':");
scanf("%f", &h);
x=0;
a=0;
do
{
    y=(cos(x)/sqrt(x));
    if (x!=0)
    {
        a=a+(0.5*h*(y+z));
    }
    (z=y);
    (x=x+h);
}
while ((z<cos(x)/sqrt(x) - PRECISION) || (z>cos(x)/sqrt(x) + PRECISION));

printf("integral between 0 and infinity=%f", a);

}

All I'm getting when I run this is 1.#INF00, and I don't know what that means

[TheBigH]

You're starting at x=0, right? cos(0)=1 and sqrt(0)=0, so what is cos(0)/sqrt(0) going to be?

[ljl22]

Ah, I see your point. Thankyou