# Documentation/Calc Functions/ASIN

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ASIN

Mathematical

## Summary:

Returns the inverse trigonometric sine (the arcsine) of a number. This function calculates the principal value.

ASIN(Number)

## Returns:

This function returns the inverse trigonometric sine of Number, that is the angle (in radians) whose sine is Number. The angle returned is between -PI/2 and +PI/2, i.e. [-π/2,+π/2].

## Arguments:

Number is the real number, or a reference to a cell containing that number, must be from -1 to 1, whose inverse trigonometric sine value is to be calculated.

If the value of Number is outside this range, it returns an invalid numeric value (#NUM!) error.

• To return the angle in degrees, use the DEGREES function.
• Alternatively multiply by 180/PI() to convert the result from radians to degrees.

The figure below illustrates the function ASIN.

## Examples:

Formula Description Returns
=ASIN(0) Inverse trigonometric sine of 0 0 (radians)
=ASIN(1) Inverse trigonometric sine of 1 1.5707963267949 (PI/2 radians or π/2)
=DEGREES(ASIN(0.5)) Inverse trigonometric sine of 0.5. Further, converting angle in radians to degrees. 30° (degrees)
=ASIN(-0.5)*180/PI() Inverse trigonometric sine of -0.5. Further, converting angle in radians to degrees by multiplying by 180/PI(). -30° (degrees)
=ASIN(2) Inverse trigonometric sine of 2 will return an invalid numeric value (#NUM!) error because 2 is out of its domain. #NUM!

ASIN