If cos x = sin(20 + x)° and 0° < x < 90°, the value of x is
°.

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Danutz98 Danutz98 · Answer 1 · 2019-05-22T13:00:20-04:00

cos x = sin(20 + x)

sin(90-x) = sin(20+x)

=> 90-x = 20+x => 2x = 70 => x = 35

We need only x ∈ (0,90) so this is the only answer.

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