Math Functions

Use of math functions

The standard mathematical functions defined and kept as a part of C math library.We must add an instruction as follows:

 #include<math.h>

Math functions

function       Meaning

Trigonometric     

cos(x)            Cosine of x

sin(x)             Sine of x

tan(x)            Tangent of x

acos(x)          Arc cosine of x

asin(x)           Arc sine of x

atan(x)          Arc tangent of x     

atan2(x,y)     Arc tangent of x/y

Hyperbolic

cosh(x)         Hyperbolic cosine of x

sinh(x)          Hyperbolic sine of x

tanh(x)         Hyperbolic tangent of x

Other functions

ceil(x)           x rounded up to the nearest                      

                       integer

exp(x)          e to the x power

fabs(x)         Absolute value of x

floor(x)        x rounded down to the                                 

                      nearest integer

fmod(c)        Remainder of x/y

log(x)           Natural log of x,x>0

log10(x)       Base 10 log of x,x>0

pow(x,y)      x to the power y
sqrt(x)          Square root of x,x>=0

1.A C program  which accepts an angle and gives sine and cosine value.

#include<stdio.h>

#include<conio.h>

#include<math.h>

void main()

{

int degree;

float angle;

float x,y;

clrscr();

  printf("Enter angle in degree:");

  scanf("%d",&degree);

angle=(degree*3.1416)/180;

x=sin(angle);

y=cos(angle);

  printf("sin(%d°)=%f",degree
,x);

printf("\ncos(%d°)=%f",degree
,y);

getch();

}

Output:

Enter angle in degree:30

sin(30°) = 0.500001

cos(30°) = 0.866025

2.A C program to find out the roots of the quadratic equation.

#include<stdio.h>

#include<conio.h>

#include<math.h>

void main()

{

float a,b,c,discriminant,root1,root2;

printf("Enter values of a,b and c of the quadratic equation:\n");

scanf("%f%f%f",&a,&b,&c);

discriminant=b*b-4*a*c;

if(discriminant<0)

{

printf("Roots are imaginary\n");

}

else

{

root1=(-b+sqrt(discriminant))/(2*a);

root2=(-b-sqrt(discriminant))/(2*a);

printf("Roots are:\n%f\n%f",root1,root2);

}

getch();

}

Output:

Enter values of a,b and c of the quadratic equation:

2 6 1

Roots are:

-0.177124

-2.822876

Another output:

Enter values of a,b and c of the quadratic equation:

4 2 1

Roots are imaginary