tan^x*cos^2x can be replaced with sin^2x, since tan^2x = sin^2x/cos^2x
cos^2 + sin^2x = 1
q.e.d.
Verify only working with one side:
cos^2x + tan^2x cos^2x = 1
2 answers
Thank you.!
cos^2x + tan^2x cos^2x = 1
2 answers