SOLUTION: Write the expression as the​ sine, cosine, or tangent of a​ double-angle. Then find the exact value of the expression. cos^2 135 degrees - sin^2 135 degrees

Algebra.Com
Question 1087806: Write the expression as the​ sine, cosine, or tangent of a​ double-angle. Then find the exact value of the expression.
cos^2 135 degrees - sin^2 135 degrees
Answer by ikleyn(52794)   (Show Source): You can put this solution on YOUR website!
.
cos^2(135°) - sin^2(135°) = cos(135°)*cos(135°) - sin(135°)*sin(135°) =  (apply the adding formula for cosine) = 

= cos(135° + 135°) = cos(270°) = 0.

Solved.


RELATED QUESTIONS

Rewrite the expression as the​ sine, cosine, or tangent of a​ double-angle.... (answered by greenestamps)
write the expression as sine, cosine or tangent of an angle. Then find the exact value of (answered by Alan3354)
Write the expression as the sine, cosine, or tangent of an angle. cos 94° cos 37° +... (answered by Century)
Write the expression as the sine, cosine, or tangent of an angle. sin 5x cos x - cos... (answered by tommyt3rd)
Write the expression as the sine, cosine, or tangent of an angle. cos 112° cos 45° +... (answered by ikleyn,MathTherapy)
DOUBLE ANGLE IDENTITIES 1. Use the double angle identities to find the exact value of... (answered by Alan3354)
Write the expression as either the sine, cosine, or tangent of a single angle. sin (... (answered by josgarithmetic)
how do i write tan 25 + tan 5 / 1 - tan 25 tan 5 as the sine, cosine or tangent of an... (answered by DrBeeee)
write the expression as sine, cosine or tangent of a single angle. cos(pi )/(6)cos(pi... (answered by ikleyn)