Question

упростите выражения:
sin²a-1=
cos²a-1=
(1+sin a)(1-sin a)=
(cos a-1)(1+cos a)=

Answer 1

sin²a-1=-(1-sin²a)=-cos²a
cos²a-1=-(1-соs²a)=-sin²a
(1+sin a)(1-sin a)=1-sin²a=cos²a
(cos a-1)(1+cos a)=cos²a-1=-(1-соs²a)=-sin²a

Answer 2

сos^2a-sin^2+1=2сos^2a-

Answer 3

1-sin2a/cos2a-1