一个高等数学的问题，请高手解答一下

求极限问题！求高手解答高数的问题

有界: 先证明 当 n >= 4, x_n = 4, x_n > -(1+5^(1/2))/2。 x_4 = -2^(1/2) > -(1+5^(1/2) )/2。 假设x_n > -(1+5^(1/2) )/2, 则 x_{n+1} = -(1-x_n)^(1/2) > -(1+ (1+5^(1/2))/2 )^(1/2) = -((3+5^(1/2))/2 )^(1/2) = -(1+5^(1/2) )/2。 即当 n >= 4, -(1+5^{1/2})/2 (x_n)^2 + x_n - 1 (x_n)^2 -x_n x_(n+1) a = -(1+5^{1/2})/...全部

  有界: 先证明 当 n >= 4, x_n = 4, x_n > -(1+5^(1/2))/2。 x_4 = -2^(1/2) > -(1+5^(1/2) )/2。 假设x_n > -(1+5^(1/2) )/2, 则 x_{n+1} = -(1-x_n)^(1/2) > -(1+ (1+5^(1/2))/2 )^(1/2) = -((3+5^(1/2))/2 )^(1/2) = -(1+5^(1/2) )/2。
   即当 n >= 4, -(1+5^{1/2})/2 (x_n)^2 + x_n - 1 (x_n)^2 -x_n x_(n+1) a = -(1+5^{1/2})/2 因为 a < 0。
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