

Giúp mình với ạ
Rút gọn
A=[tex]tan(\alpha -\pi ).cos(\alpha -\pi).cos(\alpha -\frac{\pi }{2})[/tex]
B=[tex]sin(\pi+\alpha)-cos(\frac{\pi}{2}-\alpha)+tan(\frac{3\pi}{2}-\alpha)+cot(2\pi-\alpha)[/tex]
Rút gọn
A=[tex]tan(\alpha -\pi ).cos(\alpha -\pi).cos(\alpha -\frac{\pi }{2})[/tex]
B=[tex]sin(\pi+\alpha)-cos(\frac{\pi}{2}-\alpha)+tan(\frac{3\pi}{2}-\alpha)+cot(2\pi-\alpha)[/tex]