已知3π/4
问题描述：
已知3π/4
答
tanα+1/tanα=-10/3,tana=-3,或tana=-1/3[5sin²a/2+8sina/2 cosa/2+11cos²a/2-8]/√2sin(a-π/4)=[5sin²a/2+5cos²a/2+8sina/2 cosa/2+6cos²a/2-8]/√2[sinacos(π/4)-cosasin(π/4)]=[-3+...