Question

cos⁴a+sin²a×cos²a упроситите и найдите его значиние при tga=2​

Answer 1

$Cos^{4}\alpha+Sin^{2}\alpha Cos^{2}\alpha =Cos^{2}\alpha(Cos^{2}\alpha +Sin^{2}\alpha)=Cos^{2} \alpha*1=Cos^{2}\alpha\\\\1+tg^{2}\alpha=\frac{1}{Cos^{2}\alpha}\\\\Cos^{2}\alpha=\frac{1}{1+tg^{2}\alpha}=\frac{1}{1+2^{2} }=\frac{1}{5}=0,2$