Question

F（x）=∫从1积到x (lnt)/(1+t^2)dt (x>0),求F（x）-F(1/x)

Answer 1

#include

#include

#define N 10000000 /*把1到x分成N份,这是微元法的拆分步骤*/

main()

{

double fun(double);

double x,t,dt,df,sum=0.0;

long j;

printf("input x: ");

scanf("%lf",&x); /*输入时注意x的定义域：t>0,所以输入的t必须大于0*/

dt=(x-1)/N;

for(j=1;j