Question

10 класс алгебра !! 128(Б)!

Answer 1

$sin( alpha - beta ) =sin alpha cos beta +sin beta cos alpha ,\sin(- alpha )=-sin alpha , cos(- beta )=cos beta . \\sin{left( alpha - beta right)}+sin{left(- alpha right)}cos{left(- beta right)}=sin{left( alpha - beta right)}+left(-sin{alpha}cos{beta}right)=\=sin alpha cos beta +sin beta cos alpha -sin{alpha}cos{beta}=sin beta cos alpha .$