∫(13t - 3)/(13t^2 - 18t + 9) dt = (1/2)*log(13t^2-18t+9) + arctan{(13t-9)/6} + C より、
∫[t=1〜2] (13t - 3)/(13t^2 - 18t + 9)=log(5/2)+arctan(17/6)-arctan(2/3)=log(5/2)+arctan(3/4)