[c++]confused about cosinus

CorDharel · 03-05-2004, 09:46 PM

Hi all!

Could anyone tell me why my calculator shows the value "0.91354646" and my c++ program shows "0.424179"?

I wanted to try the functions in the class "cmath.h" but it didn't work how it seems

Code:

#include <iostream>
#include <cmath>

int main()
{

	float x;

	x = cos(24);

	printf("\n\nCos value of x: %f\n\n",x);

}

crabboy · 03-05-2004, 10:16 PM

The cos function takes its input in radians, your calculator is using degrees.

CorDharel · 03-08-2004, 12:13 PM

I only remember these 2 thingies when I had an error in my calculator and had to set it up. What is the difference between these 2?

crabboy · 03-08-2004, 11:07 PM

http://math.rice.edu/~pcmi/sphere/drg_txt.html

Code:

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

#define PI 3.14159265358979

double deg2rad( double d )
{
   return (( d / 180 ) * PI );
}

double rad2deg( double r )
{
   return (( r / PI ) * 180 );
}

int main( void )
{
   printf( "cos value of x: %f\n", cos( deg2rad( 24 )));
}