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#include <math.h>

double tan (
  double x);   /* value to calculate tangent of */

The tan function calculates the tangent of the floating-point value x.

Return Value

The tan function returns the tangent of x.

The value of x must be in the range ±2^32 (±4294967296.0). Outside this value range an NaN error is returned.

For x = c (±π/2), {c = (2k+1); k ∈ N}, tan returns ±INF.

See Also

cos, sin

#include <math.h>
#include <stdio.h> /* for printf */

void tst_tan (void) {
  float x;
  float y;
  float pi;

  pi = 3.14159265;

  for (x = -(pi/4); x < (pi/4); x += 0.1) {
    y = tan (x);
    printf ("TAN(%f) = %f\n", x, y);
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