Question

найдите значение tg^2a если sin^2a=4/5

Answer 1

$sin^2a= frac{4}{5}\ tg^2a=?\\tg^2a= frac{sin^2a}{cos^2a}\cos^2=1-sin^2a=1- frac{4}{5}= frac{1}{5}\\tg^2a= frac{4}{5} : frac{1}{5}= frac{4}{5} * frac{5}{1}= 4$