SOLUTION: Use a cofunction identity to write an equivalent expression. cos(20�)

SOLUTION: Use a cofunction identity to write an equivalent expression. cos(20�)

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Question 1105164: Use a cofunction identity to write an equivalent expression.
cos(20�)
Answer by ikleyn(52814) (Show Source): You can put this solution on YOUR website!
.

cos(a) = sin(90�-a)  ====>


cos(20�) = sin(90�-20�) = sin(70�).

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