Question

a = \(\cos^252\)độ . sin 45độ + \(\sin^245\)độ . sin 45độ  

Answer 1

\(A=cos^258^0\cdot sin45+sin^245^0+sin45\)

\(=sin45\left(cos^258^0+sin^245^0\right)\)

\(=\dfrac{\sqrt{2}}{2}\left(cos^258^0+\dfrac{1}{2}\right)\)

\(=\dfrac{\sqrt{2}}{2}\cdot cos^258^0+\dfrac{\sqrt{2}}{4}\)