Solving single variable equation where other variables depends on that single variable

Question

Dhananjay Singh 2021-9-10

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https://ww2.mathworks.cn/matlabcentral/answers/1450579-solving-single-variable-equation-where-other-variables-depends-on-that-single-variable

编辑： Alan Stevens 2021-9-10

采纳的回答： Alan Stevens

Is there a method to solve equations like :

lets say we first define a variable x initial value unknown and we know y = f(x) ; z = f(y) ; p = f(z).

Now the equation to be solved is like 250 = x + y + z where after solving we find x and we need the final value of p.

I have used iteration to solve this but that takes a long time. Any method would be appreciated.

Thanks

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Answer 1

Alan Stevens 2021-9-10

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https://ww2.mathworks.cn/matlabcentral/answers/1450579-solving-single-variable-equation-where-other-variables-depends-on-that-single-variable#answer_784659

编辑：Alan Stevens 2021-9-10

在 MATLAB Online 中打开

Try using fzero. For example:

f = @(x) x.^2 +1./x;   % arbitrary function: replace with your own
y = @(x) f(x);
z = @(x) f(y(x));
p = @(x) f(z(x));
g = @(x) x + y(x) +z(x) - 250;
% Initial guess
x0 = 1;
x = fzero(g, x0);
format long
disp([x, p(x)])
   1.0e+04 *

   0.000386468834515   5.333363091026294