已知3π/4已知3π/4(1)求tana的值.(2)求(5sin^2a/2+8sina/2cosa/2+11cos^2a/2-8)/根号2sin(a-π/2).(2)求(5sin^2a/2+8sina/2cosa/2+11cos^2a/2-8)/根号2sin(a-π/2)
已知3π/4设tana=x,即x+1/x=-10/3,解之x=-1/3