# how to solve two unknowns in two complicated eqns

Discussion in 'MATLAB' started by Yi, Apr 28, 2009.

1. ### YiGuest

Dear matlab friends:

I have two very complicated eqns, like this:
x = f(x,y)
y = f'(x,y)
both f and f' are very very complocated,
for example f(x,y) = cosxy + siny +y/28*e^xy+ log(x/y^1.41)+....

I cannot use "solve" to solve it cause it seems take forever to get the solution.

How to write a code to solve these two eqns?

I wrote a fix-point iteration code to solve one unknown with one eqn. But I don't know how to write a code for several unknown variables.

Any suggestion is welcome.

Thanks & Best Regards

Yi

Yi, Apr 28, 2009

2. ### FengGuest

what do you mean 'very very complicated'?
the variables are x and y?
so you get eq1: f(x,y) - x = 0; eq2: f'(x,y) - y = 0;
if you just want to get the values of these two varialbes, try fsolve, give initial guess.

Feng, Apr 28, 2009

Ask a Question

## Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.