Question

Помогите пожалуйста!!!

Answer 1

Возможно, я не до конца упростила...
$cos^{3}( alpha )=cos alpha *cos^{2}( alpha )=cos alpha *(1-sin^{2}( alpha ))$ = $cos alpha -cos alpha *sin^{2}( alpha)$
$sin^{3}( alpha )=sin alpha *sin^{2}( alpha )=sin alpha *(1-cos^{2}( alpha ))$
Числитель: $cos alpha -cos alpha *sin^{2}( alpha)+sin alpha -sin alpha *cos^{2} alpha$=$(cos alpha +sin alpha )(1-cos alpha *sin alpha)$

Дробь: $frac{(cos alpha +sin alpha )(1-cos alpha *sin alpha)}{(1-sin alpha *cos alpha )*sin^{2} alpha } -ctg alpha$ = $frac{(cos alpha +sin alpha )}{sin^{2} alpha } - frac{cos alpha }{sin alpha }$ = $frac{cos alpha +sin alpha -cos alpha *sin alpha }{sin^{2} alpha }$ = $frac{cos alpha }{sin^{2} alpha } + frac{sin alpha }{sin^{2} alpha } - frac{sin alpha *cos alpha }{sin^{2} alpha }$ = $frac{ctg alpha }{sinalpha } + frac{1}{sin alpha } - frac{cos alpha }{sinalpha }= frac{ctg alpha +1-cos alpha }{sin alpha }$