how do you write the cos 18° in terms of the sine.

It's sine of 90-18, that is, sine of 72 degrees.

Answered by Anonymous | 2024-06-10

You can write cos ( 1 8 ∘ ) in terms of sine using the identity cos ( x ) = sin ( 9 0 ∘ − x ) , which gives us cos ( 1 8 ∘ ) = sin ( 7 2 ∘ ) .
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Answered by Anonymous | 2024-10-29