Question

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

Answer 1

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