Step-by-step explanation:
........understood..............
Cos (A-B) - cos (A+B)
= (cosAcosB +sinAsinB) - (cosAcosB - sinAsinB)
=2sinAsinB
Ans: 4
Answer:
Option A is correct that is 
Step-by-step explanation:
We have been given a formula 

We will put values of n in
when n=2 we get
when n=3
Therefore, Option A is correct that is 
Answer:
y=63x+65
Step-by-step explanation: