Question

если tga=2, тогда найди tg²a+2cos²a​

Answer 1

$tg\alpha =2\ \ \ \ tg^2\alpha +2*cos^2\alpha =?$

Объяснение:

$tg\alpha =\frac{sin\alpha }{cos\alpha } =2\\tg^2\alpha =\frac{sin^2\alpha }{cos^2\alpha } =4\\sin^2\alpha =4*cos^2\alpha \\sin^2\alpha +cos^2\alpha =4*cos^2\alpha+cos^2\alpha \\1=5*cos^2\alpha\ |:5 \\cos^2\alpha= \frac{1}{5}=0,2\ |*2\\ 2*cos^2\alpha =0,4.\\tg^2 \alpha +2**cos^2\alpha =4+0,4=4,4.\\tg^2\alpha +2cos^2\alpha =4,4.$