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Chapter 12 Trigonometric Functions 333

COS

The COS function returns the cosine of an angle that is expressed in radians.

COS(radian-angle)

Â radian-angle: An angle, expressed in radians. radian-angle is a number value.

Although it can be any value, it would normally be in the range –π to +π (–pi to +pi).

Usage Notes

To return an angle in degrees, use the DEGREES function (to convert radians to Â

degrees) with this function; that is, =DEGREES(COS(radian-angle)).

Examples

=COS(1) returns 0.540302306, the cosine of 1 radian (approximately 57.3 degrees).

=COS(RADIANS(60)) returns 0.5, the cosine of 60 degrees.

=COS(PI()/3) returns 0.5, π/3 radians (60 degrees).

=COS(PI()) returns –1, the cosine of π radians (180 degrees).