Ctga-3cos^2a-3sin^2a если tga=2

Question

Ctga-3cos^2a-3sin^2a если tga=2

Answer 1

Cotga.tga=1,cotga=1/tga=1/2
cotga-3.cosˇ2a-3sinˇ2a=1/2-3(cosˇ2a+sinˇ2a´=1/2-3.1=1/2-3=-5/2