How to solve multiple equations dependent on each other?

Hi

How to code this situation?

I have two equations, which are dependent on each other. Y=2X+5----(1) and X=2Y+5-----(2) The initial value of X=1, then I have to solve these equation repeatedly for 10 times.

Thanks

Answer 1

[Niels]

Since you depend on your previous answers, you can simply loop through the equations and store the answers.

x = ones(1,10); % also contains your initial x
y = ones(1,10); % just to preallocate y as well

for i=1:9              % loop 9 times
  y(i) = 2*x(i) + 5;   % calculate the y-value
  x(i+1) = 2*y(i) + 5; % calculate the 'next' x-value
end
y(10) = 2*x(10) + 5;   % finish off by calculating the final y-value

If you only care about the final value, this suffices:

x = 1;

for i=1:9
  y = 2*x + 5; % calculate the y-value
  x = 2*y + 5; % calculate the 'next' x-value
end

y = 2*x + 5;