Question

sin 2x =2 sin x -cos x +1

Answer 1

Ответ:

Решение:  

1) Sin (x-1) = cos (x+2)  

Sin (x-1) - cos (x+2)=0  

Sin (x-1) - sin(π/2- (x+2))=0  

2sin(π/4-3/2)*cos(x+1/2-π/4)=0  

cos(x+1/2-π/4)=0  

x+1/2-π/4=π/2+πn  

x=π/2-1/2+π/4+πn  

x=3π/2-1/2+πn  

2) Sin x Sin 5x = Cos 4x;  

1/2(cos(-4x)-cos6x)-cos4x=0  

cos4x-cos6x-2cos4x=0  

cos6x+cos4x=0  

2cos5x*cosx=0  

a) cos5x=0  

5x=π/2+πn  

x1=π/10+πn/5  

б) cosx=0  

x2=π/2+πn

Пошаговое объяснение: