Question

Доказать тождество:

1- cos(2П-2а)/1-cos^2(а+П)=2

 

 

Answer 1

$frac{1-cos(2 pi -2 alpha ) }{1-cos^2( alpha + pi )}=2;$
$frac{1-cos2 alpha }{1-cos^2alpha}=2;$
$frac{2sin^2 alpha }{sin^2alpha}=2;2=2.$