作业帮已知3π/4
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 12:09:15
已知3π/4
已知3π/4
已知3π/4
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+4sina+6cos²a/2]/(sina-cosa)
=(4sina+3cosa)/(sina-cosa)
=(4tana-3)/(tana-1)
当tana=-3时
=-15/(-4)
=15/4
当tana=-1/3时
＝13/4