These are the questions please give the answer with the steps how did you get it :
1. Use the sum/difference formula to find the exact value of the following.
a) cos 11π/12
b) tan 165◦
2. Evaluate cos(θ − φ), where cos θ = 7/25 with θ in Quadrant IV, and tan φ = −√3 with φ in Quadrant II.
3. Given that tanθ = 1/−3, and cosθ > 0, find sin2θ, cos2θ, and tan2θ.
4. Use the appropriate Half-Angle Formula to find the exact value of each expression.
a) sin 15◦
b) sin 157.5◦
c) cos 11π/8
5. Find the general solution of cos θ = − 1/2