题目13.设数列(xn)满足 lt (x)_(1)lt pi , _(n+1)=sin (x)_(n)(n=1,2,... ).-|||-(1)证明:limxn存在,并求该极限.-|||-n→∞-|||-(2)计算 lim _(narrow infty )((dfrac {{x)_(n+1)}({x)_(n)})}^dfrac (1{{{x)_(n)}^2}}题目解答答案