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Inverse cosine, result in radians



Y = acos(X) returns the inverse cosine (arccosine) for each element of X. For real elements of X in the domain , acos(X) is real and in the range . For real elements of X outside the domain , acos(X) is complex.

The acos function operates element-wise on arrays. The function's domains and ranges include complex values. All angles are in radians.


Graph the inverse cosine function over the domain .


The inverse cosine can be defined as


acos uses FDLIBM, which was developed at SunSoft, a Sun Microsystems, Inc. business, by Kwok C. Ng, and others. For information about FDLIBM, see

See Also

acosd, acosh, cos

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