1/x^6dx=-1/5d(1/x^5)udv=uv-vdu分部求，也可以查高数课本后的积分表>> syms x>> int(1/(x^6*sqrt(x^2+1))) ans = -(x^2 + 1)^(1/2)*(8/(15*x) - 4/(15*x^3) + 1/(5*x^5))
