Let U1 = 1, U2 = 1, UN + 1 = 2un + 3un-1 (n = 2,3,...) ) bn=Un/Un+1(n=2,3,…… )Prove the existence of limbn, and discuss the convergence and divergence of series 1 / UN Here is my own solution The characteristic equation is R ^ 2-2r-3 = 0, R1 = - 1, R2 = 3, the general solution U (n) = C1 * (- 1) ^ n + C2 * 3 ^ n, UN = 3 ^ n-3 * (- 1) ^ n] / 6, then BN = 1 / 3, and then find the reciprocal of BN to get the divergence But I don't think it's right. Eigenvalue? Will solve, the original difference equation, I did not want to be detailed

Let U1 = 1, U2 = 1, UN + 1 = 2un + 3un-1 (n = 2,3,...) ) bn=Un/Un+1(n=2,3,…… )Prove the existence of limbn, and discuss the convergence and divergence of series 1 / UN Here is my own solution The characteristic equation is R ^ 2-2r-3 = 0, R1 = - 1, R2 = 3, the general solution U (n) = C1 * (- 1) ^ n + C2 * 3 ^ n, UN = 3 ^ n-3 * (- 1) ^ n] / 6, then BN = 1 / 3, and then find the reciprocal of BN to get the divergence But I don't think it's right. Eigenvalue? Will solve, the original difference equation, I did not want to be detailed

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