>>242
a(x-tanθ)(x-1/tanθ)=0 ax^2-a(tanθ+1/tanθ)x + a =0=ax^2-2√2x+1=0
a(tanθ+1/tanθ)=2√2, a=1 -->(1);
tan+1/tan=2√2, sin/cos+cos/sin=1/(sincos)=2√2, sinθcosθ=1/(2√2) -->(2)
2sin(2θ)=1/√2, sin(2θ)=1/√2, 2θ=π/4(0<2θ<π),　θ=π/8 -->(3)