利用重要极限，具体解答如下图
11. [(3x+2-3)/(3x+2)]^(x+1) = [1-3/(3x+2)]^(x+1) = 112. (sqrt(x)-2)*(sqrt(x)+2)/(x-4)*1/(sqrt(x)+2) = (x-4)/(x-4) *1/(sqrt(x)+2) = 1/4
