Question

УПРОСТИТЕ
ПОМОГИТЕ ПОЖАЛУЙСТА!!!!

Answer 1

Объяснение:

1.

$cos(\frac{\pi }{4}+\alpha )-cos(\frac{\pi }{4}-\alpha )=-2* sin\frac{\frac{\pi }{4}+\alpha +\frac{\pi }{4}-\alpha }{2}*sin\frac{\frac{\pi }{4}+\alpha -\frac{\pi }{4}+\alpha }{2} =\\=-2 *sin\frac{\pi }{4}*sin\alpha =-2*\frac{\sqrt{2} }{2}*sin\alpha =-\sqrt{2}*sin\alpha .$

2.

$sin(\frac{\pi }{4}+a)-sin(\frac{\pi }{4}-\alpha )=2*sin\frac{\frac{\pi }{4}+\alpha -\frac{\pi }{4} +\alpha }{2} *cos\frac{\frac{\pi }{4}+\alpha +\frac{\pi }{4}-\alpha }{2}=\\=2*sin\alpha *cos\frac{\pi }{4} = 2*sin\alpha *\frac{\sqrt{2} }{2} =\sqrt{2}*sin\alpha .\ \ \ \ \Rightarrow$

3.

$\frac{-\sqrt{2} *sin\alpha }{\sqrt{2}*sin\alpha }=-1.$