Evaluate cos 48º cos 42º − sin 48º sin 42º
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Answer:
Step-by-step explanation:
We can change cosx into sinx by subtracting 90 from the angle.
=cos48°cos42°-sin48°sin42°
=sin(90°-48°)sin(90°-42°)-sin48°sin42°
=sin42°sin48°-sin48°sin42°
=0
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