Question

If tan (A + B) = 5 tan A, then which of the following is correct
1. 2 sin (2A + B) = 3 sin B
2. cos (2A + B) = 3 cos B
3. 2 sin (2A + B) = 3 sin A
4. 2 cos (2A + B) = 3 cos A​

Answer 1

Answer:

tan ( a+b) = tan a+tan b / 1- tan a .tan b = 3

tan a +tan b = 5- 5 tan a .tan b .............(1)

tan (A-B) = tan a- tan b = 3+3 tan a .tan b .......(2)

now by adding eq 1 and 2 u will get ur ans