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Cosine of an argument in radians



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

Y = cos(X) returns the circular cosine for each element of X.


Graph the cosine function over the domain .

The expression cos(pi/2) is not exactly zero but a value the size of the floating-point accuracy, eps, because pi is only a floating-point approximation to the exact value of .


The cosine can be defined as


cos 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

acos, acosh, cosd, cosh

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