Question

Докажите тождество а) (sin a/2 -cos a/2) ²= 1 - sin a

Answer 1

sin^a/2-2sin a/2•cos a/2+cos^a/2=1-sin a
1-sin a=1-sin a
(sin^ a/2+cos^a/2=1; и -2sin a/2cos a/2=-sin 2•a/2=-sin a)