1/(x²+2x - 1)令 t = x+1 即 x = t-1代入得 1/(t² - 2) = - 1/2 *1/(1 - t²/2)根据公式 1/(1-x) = 1+x+x²+……+x^n+……1/(t² - 2) = - 1/2 *1/(1 - t²/2)= -1/2 [ 1+ t²/2 +(t&...