Question

Which expression is equivalent? (Picture included)

Answer 1

Try multiplying the numerator and denominator by \(\bf1 + cos~\theta\) or by \(\bf 1-cos~\theta\).

This will come in handy when multiplying it:
\(\bf (a + b)(a -b) = a^2 - b^2\)
\(\bf (a + b)(a + b) = (a+b)^2\)
\(\bf (a-b)(a-b) = (a-b)^2\)

Answer 2

Okay.I'm not sure I did it right but I got D?

Answer 3

D is correct!