tan function — Computes tangent
float tan(float x) double tan(double x) long double tan(long double x)
The tan
function returns
the tangent of its argument. The standard does not specify the
result when the tangent is undefined (that is, when x
is k
π +π/2 for any integer k
), but a reasonable result is a range
error. Due to the nature of the tangent function, the sign of the
return value (HUGE_VAL
) can be
positive or negative.