int((x^4-2*x^3-x^2+2*x)/(x^2-x+1), x = -1 .. 1)

-16/3+sqrt(3)*Pi

https://drive.google.com/open?id=1hc1kUxWEDIWcc_l-hJc5GlwpJMRbVyM9 here is the solution

int(x/(x^2+x+1), x = -1 .. 1)

-(1/6)*sqrt(3)*Pi+(1/2)*ln(3)

https://drive.google.com/open?id=1hc1kUxWEDIWcc_l-hJc5GlwpJMRbVyM9here is the solutionint(x/(x^2+x+1), x = -1 .. 1)

-(1/6)*sqrt(3)*Pi+(1/2)*ln(3)