C has many simple math operations built into the language, but the math.h library offers more functions.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main() {
printf("%.0f\n", sqrt(81)); // square root 9
printf("%.0f\n", pow(6, 3)); // power 216
printf("%.0f\n", ceil(12.34)); // ceiling 13
printf("%.0f\n", floor(12.34)); // floor 12
printf("%d\n", abs(-12)); // absolute 12.000000
printf("%lf\n", cos(43.21)); // floor 0.716310
printf("%lf\n", sin(43.21)); // ceiling -0.697783
printf("%lf\n\n", tan(43.21)); // ceiling -0.974135
printf("%lf\n", M_PI); // pi 3.141593
printf("%lf\n", M_SQRT2); // sqrt(2) 1.414214
printf("%lf\n", M_E); // e 2.718282
printf("%lf\n", M_LOG2E); // log2 e 1.442695
return(0);
}