化简cos(a-3π)/sin(a+5π)*sin(a-2π)化简cos(a-3π)/sin(a+5π)*sin(a-2π)*cos(2π-a)

问题描述:

化简cos(a-3π)/sin(a+5π)*sin(a-2π)
化简cos(a-3π)/sin(a+5π)*sin(a-2π)*cos(2π-a)