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Iterative function with powers

My note book is fails to run when I introduce the power (a) on some of the functions.I can't find where am going wrong

POSTED BY: Sam Rametse
5 Replies
Posted 5 years ago
POSTED BY: Bill Nelson
a = 1.1; b = 0.02; c = 0.035; d = 1.0; k = 0.3; e = 0.5; f = 0.2; \
    \[Alpha] = 0.98; h = 1; n = 1 + t; U[0] = 0.3; V[0] = 0.2; W[0] = 0.5;


Subscript[S, 1][
       t_] := (t - 1)/\[Alpha] ((n + 1) - (t + 1))^\[Alpha] - (t + 
          1)/\[Alpha] ((n + 1) - (t + 1))^\[Alpha] - 
       1/(\[Alpha] (\[Alpha] + 1)) ((n + 1) - (t + 1))^(\[Alpha] - 
         1) - ((t - 
            1)/\[Alpha] ((n + 1) - (t))^\[Alpha] - (t)/\[Alpha] ((n + 
              1) - (t))^\[Alpha] - 
         1/(\[Alpha] (\[Alpha] + 1)) ((n + 1) - (t))^(\[Alpha] - 1));
    Subscript[S, 2][
       t_] := (t)/\[Alpha] ((n + 1) - (t + 1))^\[Alpha] - (t + 
          1)/\[Alpha] ((n + 1) - (t + 1))^\[Alpha] - 
       1/(\[Alpha] (\[Alpha] + 1)) ((n + 1) - (t + 1))^(\[Alpha] - 1) + 
       1/(\[Alpha] (\[Alpha] + 1)) ((n + 1) - (t))^(\[Alpha] - 1);
    Ut = U[t] == 
       U[0] + 1/
         Gamma[\[Alpha]] ((U[t] c d (V[t])^a - f c V[t] (U[t])^a)/
            h Subscript[S, 1][
             t] - (b ( 
               U[t - 1] c d V[t - 1]^a - f c V[t - 1] (U[t - 1])^a))/
            h Subscript[S, 2][t]);
    Vt = V[t] == 
       V[0] + 1/
         Gamma[\[Alpha]] ((c f (1 - 2 V[t] - W[t]) (U[t])^a + 
              d c (V[t])^a U[t])/
            h Subscript[S, 1][
             t] - (c f (1 - 2 V[t - 1] - W[t - 1]) (U[t - 1])^a + 
              d c (V[t - 1])^a U[t - 1])/h Subscript[S, 2][t]);
    Wt = W[t] == 
       W[0] + 1/
         Gamma[\[Alpha]] ((d f (1 - V[t] - W[t]) (U[t])^a)/
            h Subscript[S, 1][
             t] -  (d f (1 - V[t - 1] - W[t - 1]) (U[t - 1])^a)/
            h Subscript[S, 2][t]);
POSTED BY: Sam Rametse

The exponent makes the system non-algebraic. Don't expect too much.

POSTED BY: Gianluca Gorni

NDSolve worked well, but the numerical iterative function fails.

POSTED BY: Sam Rametse
Posted 5 years ago

If you pasted the InputForm of your problem as code by using the Code Sample button in the upper left corner of the posting window then someone could scrape the text of your problem off the screen and paste it into their notebook and experiment to see if they could find a way to get it to work. If you don't do that then anyone who wants to see if their idea works will have to type your entire system back in before they can test it. That doesn't often happen and so you likely won't get a solution.

POSTED BY: Bill Nelson
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