Question

1. sin2x/1-cos²x
2. log₃1/81-log₁₆16
3.7^x²=7^2₋x

Answer 1

1) sin2x/1-cos²x = 2sinxcosx/cos²x + sin²x - cos²x = 2sinxcosx/sin²x = 2 cosx/sinx = 2ctgx