Question #f1f92

2 Answers
Apr 23, 2017

See below.

Explanation:

Starting from the LHS.

LHS = (3 - 4sin^2A)/(cos^2A)

= [3 - (3sin^2A + sin^2A)]/(cos^2A)

= (3-3sin^2A - sin^2A)/(cos^2A)

= (3(1-sin^2A) - sin^2A)/(cos^2A)

= (3cos^2A - sin^2A)/(cos^2A)

= (3cos^2A)/(cos^2A) - (sin^2A)/(cos^2A)

= 3-tan^2A = RHS

Apr 24, 2017

LHS = (3 - 4sin^2A)/(cos^2A)

= 3/cos^2A - (4sin^2A)/cos^2A

= 3sec^2A - 4tan^2A

= 3(1+tan^2A )- 4tan^2A

= 3+3tan^2A - 4tan^2A

= 3 - tan^2A=RHS