Pl answer quickly having exam today the question is in the photograph ans of all 3 questions required

HInt
Q7. Using the formula of cos(A-B) and sin(A+B) by simplifying you can easily get the Option B, C and D.

Q8, Just by simplify replacing the value of Pn, Pn-2 and other You can get all the options correct.

Q9, By taking the help of options and assuming tan alpha = x and tan beta = y, You can easily get the answer even for this.

Thanks, Vijay