Question

化简：

tan(4π-α)sin(-2π-α)cos(-8π-α)

cos(α-π)sin(5π-α)

．

Answer 1

原式=

tan(-α)sin(-α)cos(-α)

cos(π-α)sin(π-α)

=

-tanα(-sinα)cosα

-cosαsinα

=-tanα