lim(x趋向于0)(1/x - 1/e的2x次方-1)
=lim(x趋向于0)([e的2x次方-1-x]/x[e的2x次方-1])
=lim(x趋向于0)([e的2x次方-1-x]/2x²)
=lim(x趋向于0)([2e的2x次方-1]/4x)
=∞
估计应该是e的x次方.