Question

1)sin 90градусов*sinx=2sin45 градусов*sin x/2

Answer 1

sin90=1; sin45=$sqrt{2}/2$
sinx=$sqrt{2}$sinx/2 => 2sinx/2cosx/2-$sqrt{2}$sinx/2=0 => 
sinx/2(2cosx/2-$sqrt{2}$)=0 => 
sinx/2=0 => x/2=пk => x=2пk;
Cosx/=$sqrt{2}$/2 => x/2=п/4+2пk => x=п/2+4пk и x/2= -п/4+2пk => x= - п/2+4пk

Answer 2

Спасибо))