∫1/(x^4+1)dx=1/2∫[(x²+1)-(x²-1)]/(x^4+1)dx=1/2[∫(x²+1)/(x^4+1)dx-∫(x²-1)/(x^4+1)dx]=1/2[∫(1+1/x²)/(x²+1/x²)dx-∫(1-1/x²)/(x²+1/x²)dx]=1/2[∫1/(x&...