Question

помогите пожалуйста с Алгеброй​

Answer 1

$1)Sin(\frac{\pi }{2}-\beta)-Cos\beta =Cos\beta-Cos\beta=0\\\\Otvet:\boxed{0}$

$2)\frac{tg(\frac{\pi }{4}+\alpha)-tg\alpha}{1+tg(\frac{\pi }{4}+\alpha)tg\alpha}=tg(\frac{\pi }{4} +\alpha-\alpha)=tg\frac{\pi }{4}=1\\\\Otvet:\boxed{1}$

$3)\frac{Sin2\alpha-2Sin\alpha}{Sin2\alpha+2Sin\alpha}=\frac{2Sin\alpha Cos\alpha-2Sin\alpha}{2Sin\alphaCos\alpha+2Sin\alpha}=\frac{2Sin\alpha(Cos\alpha-1)}{2Sin\alpha(Cos\alpha+1)}=\f2ac{Cos\alpha-1 }{Cos\alpha+1}=\frac{-2Sin^{2}\frac{\alpha}{2}  }{2Cos^{2}\frac{\alpha}{2}}=-tg^{2}\frac{\alpha}{2}\\\\Otvet:\boxed{-tg^{2}\frac{\alpha}{2}}$