f(x)=2sinxcosx+cos2x=sin2x+cos2xf(a/2)=sina+cosa=(√2)×sin(a+π/4)=√2/2所以sin(a+π/4)=1/2因为a∈(0,π),所以a+π/4∈(π/4,5π/4)所以a+π/4=5π/6,即a=7π/12所以tana/2=tan(7π/24)=tan(π/8+π/6)=[tan(...