Can someone explain how to use the substitution method to find the integral of:
$\displaystyle \int_{-1}^{1} \frac{2x + 1}{x^2 + x + 1}dx$
oh right.. so then i can just put in 3 and 1 for the function because if x = 1 then t = 3; if x = -1 then t = 1 so I get: (Note it's a definite integral!!!)
$\displaystyle ln(3) - ln(1)$ and that is the same as $\displaystyle ln(\frac{3}{1}) = ln(3)$
correct or have I misunderstood something?