Cos(180°+α)*sin（α+360°)/sin(-α-180°)*cos(-180°-α)

这道题是考三角函数的性质
cos(180 + a) = - cos a
sin ( a + 360) = sin a
sin(-a-180) = - sin ( a + 180 ) = sin a
cos( - 180 - a) = cos(180 + a) = - cos a
所以原式 = - cos a sin a / ( sin a * - cos a)
=1