#include<stdio.h>
#include<math.h>
#define PI 3.1415
float exp_x( int, int );
double sin_x( int, int );
double cos_x( int, int );
int fact( int );
int main()
{
int choice, x, n;
do
{
printf( "\nMenu\n[1] e^x)\n[2] Sin(x)\n[3] Cos(x)\n[4] Exit\n" );
scanf( "%d", &choice );
switch ( choice )
{
case 1: // to find exponential value
printf( "e^x\nEnter x and n:\t" );
scanf( "%d %d", &x, &n );
printf( "e^%d(%d) = %f\n", x, n, exp_x( x, n ) );
break;
case 2: // to find sinx
printf( "sin(x)\nEnter x and n:\t" );
scanf( "%d %d", &x, &n );
printf( "\ncos(%d)(%d) = %f\n", x, n, sin_x( x, n ) );
break;
case 3: // to find cosx
printf( "cos(x)\nEnter x and n:\t" );
scanf( "%d %d", &x, &n );
printf( "\ncos(%d)(%d) = %f\n", x, n, cos_x( x, n ) );
break;
case 4: // exit
break;
default: // wrong choice
printf( "Wrong choice" );
break;
}
}
while ( choice != 4 );
}
float exp_x( int x, int n )
{
int i = 1;
float ex = 1;
while ( i < n )
{
ex += ( float ) pow( x, i ) / fact( i );
++i;
}
return ex;
}
double sin_x( int ang_deg, int no_of_terms )
{
int term, j;
double value = 0.0, ang_rad = 0.0;
ang_rad = ( double ) ang_deg * PI / 180;
for ( term = 1, j = 2;term < no_of_terms*2;term += 2, j++ )
{
value += ( double ) pow( -1.0, j ) * pow( ang_rad, term ) / fact( term );
}
return value;
}
double cos_x( int ang_deg, int no_of_terms )
{
int term, j;
double value = 1.0, ang_rad = 0.0;
ang_rad = ( double ) ang_deg * PI / 180;
for ( term = 2, j = 1;term <= no_of_terms;term += 2, j++ )
{
value += ( double ) pow( -1.0, j ) * pow( ang_rad, term ) / fact( term );
}
return value;
}
int fact( int num )
{
int f = 0;
if ( num == 1 )
return 1;
else
f = num * fact( num - 1 );
return f;
}
