∫1/[x(x^6+4)]dx=(1/4)∫1/x-x^5/(x^6+4)dx=(1/4)∫1/xdx-(1/4)∫x^5/(x^6+4)dx=(1/4)ln|x|-(1/24)∫1/(x^6+4)dx^6=(1/4)ln|x|-(1/24)ln(x^6+4)+C
