Question

Simplify

(cos theta + cos theta)^2 + (cos theta + cos theta)^2
A) sin^2 Theta
B)4
C) 8cos^2 theta
D) cos^2 theta

Answer 1

Work within your parenthesis first, as you always should. Cos theta + cos theta is 2 cos theta. Square that and you have 4 cos^2 theta. Since both sets of parenthesis are exactly the same, you have
`4cos ^(2) \beta +4cos ^(2) \beta` which are like terms. Add them and you have 8 of them. So your choice is C.