化简[sin(π-α)cos(3π-α)tan(-α-π)]/[tan(4π-α)sin(5π+α)]

问题描述:

化简[sin(π-α)cos(3π-α)tan(-α-π)]/[tan(4π-α)sin(5π+α)]

sin(π-a)cos(3π-a)tan(-π-a)tan(a-2π)/tan(4π-a)sin(5π+a)
=sinacosatana/tanasina
=cosa