Question

Упростить выражение

Answer 1

$\frac{sina\cdot sin\beta -cos(a-\beta )}{ctga}=\frac{sina\cdot sin\beta -(cosa\cdot cos\beta +sina\cdot sin\beta )}{ctga}=\\\\=\frac{-cosa\cdot cos\beta }{\frac{cosa}{sina}}=-\frac{cosa\cdot cos\beta \cdot sina}{cosa}=-cos\beta \cdot sina$

Answer 2

(sinasinb-(cosacosb+sinasinb))/ctga