Function acos

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Declaration:

float acos(float x);

Description

The acos function calculates the arc cosine of the floating-point number x. Argument x should range from -1 to 1, otherwise the result will be equal to 0 (for x > 1) or to PI (for x < -1). The function returns value in the range from 0 to PI.

Returned value

The acos function returns the arc cosine of argument x.