May 2, 1991 ASIN 3

### NAME

asin, asinf - arc sine function

### LIBRARY

Math Library (libm, -lm)

### SYNOPSIS

```double` asin(```double x`)
```float` asinf(```float x`)

### DESCRIPTION

The asin(``) and asinf(``) functions compute the principal value of the arc sine of ```x` in the range [-/2, +/2].

### RETURN VALUES

If |x|>1, asin(```x`) and asinf(```x`) return NaN and set the global variable errno to EDOM.

### SEE ALSO

acos(3), atan(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3), tan(3), tanh(3)

### STANDARDS

The asin(``) function conforms to ANSI X3.159-1989 (``ANSI C89'') .