Question

Find the value of cos 15°, using the result cos (A - B) = cos A cos B + sin A sin B.

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Answer 1

Answer:

$\sqrt{3} + 1 \div 2 \sqrt{2}$

Answer 2

Step-by-step explanation:

cos(60-45)=cos60cos45+sin60sin45

=1/2×1/√2+√3/2×1/√2

=(1+√3)/2√2