Sin15°⋅cos15°⋅2(sin^2 42°+cos^2 42°)+cos58°⋅cos14°

Question

Sin15°⋅cos15°⋅2(sin^2 42°+cos^2 42°)+cos58°⋅cos14°

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Answer 1

1)sin15°⋅cos15°⋅2=sin30°=0,5;

2)sin^2 42°+cos^2 42°=1;

sin15°⋅cos15°⋅2(sin^2 42°+cos^2 42°)+cos58°⋅cos14°=

0,5+cos58°⋅cos14°