Question

1/(tana/2)-tana/2 怎么化简?

Answer 1

原式=cos(a/2)/sin(a/2)-sin(a/2)/cos(a/2)

=[cos²(a/2)-sin²(a/2)]/[sin(a/2)cos(a/2)]

=cosa/[(sina)/2]

=2cosa/sina

=2cota