图
let1/y = 3/(3x-2)lim(x->∞)((3x+1)/(3x-2))^x=lim(x->∞)(1 + 3/(3x-2))^x=lim(y->∞)(1 + 1/y)^[(3y+2)/3]=lim(y->∞)(1 + 1/y)^y=e