Without using a calculator, compute the sine and cosine of \( 120^{\circ} \) by using the reference angle. What is the reference angle? In what quadrant is this angle? \( \sin \left(120^{\circ}\right)=\square \) degrees. \( \cos \left(120^{\circ}\right)=\square \) (Type sqrt(2) for \( \sqrt{2} \) and sqrt(3) for \( \sqrt{3} \).)

Find all solutions of the equation \( 2 \cos x-1=0 \). The answer is \( A+B k \pi \) and \( C+D k \pi \) where \( k \) is any integer, \( 0<A<C<2 \pi \), \( A=\square, D=\square \) \( C=\square \)

Find an angle \( \theta \) coterminal to \( -555^{\circ} \), where \( 0^{\circ} \leq \theta<360^{\circ} \)

Which is the correct identity for cos? \( \cos \theta=\frac{h}{a} \) \( \cos =\frac{h}{a} \) \( \cos \theta=\frac{a}{h} \) \( \cos =\frac{a}{h} \)

If \( \cos (\alpha+\beta)=0 \) then \( \sin (\alpha+2 \beta) \)

Corvert the following angle from degrees to radians. Express your answer in simplest form.