Question

sin^2a-3cos^2a/2sin^2a+cos^2a если tga=5​

Answer 1

$\frac{Sin^{2}\alpha-3Co\alpha s^{2}\alpha}{2Sin^{2}\alpha+Cos^{2}\alpha} =\frac{\frac{Sin^{2}\alpha}{Cos^{2}\alpha}-\frac{3Cos^{2}\alpha}{Cos^{2}\alpha}}{\frac{2Sin^{2}\alpha}{Cos^{2}\alpha}+\frac{Cos^{2}\alpha}{Cos^{2}\alpha}}=\frac{tg^{2}\alpha-3}{2tg^{2}\alpha+1}=\frac{5^{2}-3 }{2*5^{2} +1}=\frac{25-3}{50+1}=\frac{22}{51}$