2 2dt=(2+-)d [2+2n(t-1) (6+2ln2)-(4+2lnl)=2+2ln2   −  = + − = − 9 4 3 2 3 2 )d 1 2 2 d (2 1 1 d 1 1 t t t t t x x 3 2 = [2t + 2ln(t −1)] = (6 + 2ln 2) − (4 + 2ln 1) = 2 + 2ln 2