>>349
与式=(1/√2)∫dx/sin(x+π/4)
cos(x+π/4)=t
-sin(x+π/4)dx=dt
∫dx/sin(x+π/4)=-∫{-sin(x+π/4)/(1-cos^2(x+π/4))}dx=-∫dt/(1-t^2)