Докажите тождества 1) 1-sin2x =cos 2x 2)cosB -1 = -sin 2B
3)tg x *ctg x + 4 = 5
4)cos a * tg a =sin a
5)(1-cos x)(1+cos x)=1- cos2x=sin x
6) sin2 a +2sin a * cos a +cos2 a =(sin a + cos a)2

nesen03    3   13.02.2022 17:53    0