Question

446(1,2)
пожалуйста)

Answer 1

$\frac{\sin24\cos6-\sin6\sin66}{\sin21\cos39-\sin39\cos21} = \frac{\sin24\cos6-\sin6\sin(90-24)}{\sin21\cos39-\sin39\cos21} = \\\ = \frac{\sin24\cos6-\sin6\cos24}{\sin21\cos39-\sin39\cos21} = \frac{\sin(24-6)}{\sin(21-39)} = \frac{\sin18}{\sin(-18)} = \frac{\sin18}{-\sin18} =-1$

$\frac{\sin20\cos10+\cos160\cos100}{\sin21\cos9+\cos159\cos99} = \frac{\sin20\cos10+\cos(180-20)\cos(90+10)}{\sin21\cos9+\cos(180-21)\cos(90+9)} = \\\ = \frac{\sin20\cos10+\cos20\cos10}{\sin21\cos9+\cos21\cos9} = \frac{\sin(20+10)}{\sin(21+9)} = \frac{\sin30}{\sin30} =1$