Question

Factorise cos²A + 3 Cos A + 2​

Answer 1

`(cosA +1)(cosA +2)`

Explanation:

`cos^2(A)+3cos(A)+2`

Which number add up to 3 and multiply to 2?

That would be 1 and 2.

`cos^2(A)+3cos(A)+2=(cosA +1)(cosA +2)`