Question

tg²b-sin²b·tg²b=? помогите упростить

Answer 1

  $tg^2 beta -sin^2 beta cdot tg^2 beta =tg^2 beta (1-sin^2 beta )=tg^2 beta cdot cos^2 beta =\\=frac{sin^2 beta }{cos^2 beta }cdot cos^2 beta =sin^2 beta$