Question

化简

sinacosa

cos2a-sin2a

-

tana

1-tan2a

=______．

Answer 1

sinacosa

cos2a-sin2a

-

tana

1-tan2a

=

1 2 ×2sinacosa

cos2a-sin2a

-

1 2 ×2tana

1-tan2a

=

1 2 sin2α

cos2α

-

1

2

tan2α
=

1

2

tan2α-

1

2

tan2α
=0．
故答案为：0