Question

Express as a product: 1+2cosα

Answer 1

Explanation:

1+2 cos α

`=1+2(2 cos^(2) (\alpha )/(2) -1)\\=1+4 ~cos^2(\alpha )/(2) -2\\=4 ~cos^2(\alpha )/(2) -1\\=(2cos (\alpha )/(2) +1)(2 cos (\alpha )/(2) -1)`