MATLAB Answers


Simple for loop question.

Asked by Jake
on 7 Dec 2012

I am wanting to write a for loop for 2 differential equations.

For 0<x<5 dadb = (2*x)
For 5<x<10 dadb = (3*x)

How would I code this?



Differential equations? So dadb means "the derivative of a with respect to b" ? But the value you give is in terms of a third variable, x ??

on 9 Dec 2012

Sorry i will re-write that...

For 0<x<5 dz/dx = (2*x)
For 5<x<10 dz/dx = (3*x)
Jan Simon
on 9 Dec 2012

Are you sure that you mean a FOR-loop? Look at "doc for" and "help for", if this really matches your needs.



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1 Answer

Answer by Rick Rosson
on 9 Dec 2012
Edited by Rick Rosson
on 9 Dec 2012

   dx = 0.01;
   x = (0:dx:10-dx)';
   idx = (x < 5);
   C = ...
   D = ...
   z = ( C + x.^2 / 2 ) .* idx   +   ( D + x.^3 / 3 ) .* ( 1 - idx ) ;

You will need to specify values for the constant C and D based on the initial value of z and the continuity condition at x = 5.


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