Question

Упростите выражения
Sin^2a/1+cosa

Answer 1

$frac{sin^2alpha}{1+cosalpha}=frac{sin^2alpha}{2cos^2frac{alpha}{2}}= frac{(2sinfrac{alpha}{2}cosfrac{alpha}{2})^2}{2cos^2frac{alpha}{2}}= frac{4sin^2frac{alpha}{2}cos^2frac{alpha}{2}}{2cos^2frac{alpha}{2}}= 2sin^2frac{alpha}{2}=1-cosalpha$