请教一个基本的问题 - 编程论坛

#2

rjsp2023-10-26 08:23

1/2x 是什么意思？是 (1/2)x 还是 1/(2x) ？
2x 是什么意思？是 2*x，还是 2^x ？

#3

rjsp2023-10-26 08:48

假设 1/2x 是 1/(2*x) 的话

程序代码：

double foo( unsigned n, double x )
{
    double result = 0;
    for( unsigned i=0,a=1,b=2; i!=n; ++i,b=b+a,a=b-a )
    {
        if( i%2 == 0 )
            result += a/(b*x);
        else
            result -= (a*x)/b;
    }
    return result;
}

#include <stdio.h>
#include <assert.h>

int main( void )
{
    assert( foo(1,1) == 1/2. );
    assert( foo(2,1) == 1/2. - 2/3. );
    assert( foo(3,1) == 1/2. - 2/3. + 3/5. );

    assert( foo(1,0.5) == 1/(2*0.5) );
    assert( foo(2,0.5) == 1/(2*0.5) - (2*0.5)/3 );
    assert( foo(3,0.5) == 1/(2*0.5) - (2*0.5)/3 + 3/(5*0.5) );
}

#4

A3C2023-10-26 13:57

回复 3楼 rjsp

谢谢

#5

A3C2023-10-26 17:15

x=6.66,其中2x为2*x请问有更多的解法吗，最好对初学者友好点

#6

yiyanxiyin2023-10-26 17:21

#include <stdio.h>
void main ()
{
  int i,n;
  float x,s=0,l,m=1,t,M=2,j=1;
  printf("x=");
  scanf("%f",&x);
  printf("\nn=");
  scanf("%d",&n);
  if(n>=1)
    l=m/(M*x);
  else l=0;
    s+=l;
  for(i=2;i<=n;i++)
  {
    t=m;
    m=M;
    M=M+t;
    if(i%2==0)
      l=-(m*x)/M;
    else
      l=m/(M*x);
    s+=l;
  }
  printf("\ns=%f",s);
}

#7

A3C2023-10-26 18:48

回复 6楼 yiyanxiyin

谢谢