Hi,

lately I've been working with numerical methods for finding roots of functions.

They all need some sort of initial guess. How can I find on which interval a solution might exist?

Perhaps I could test to see if $\displaystyle f(x)f(y)<0$ for a lot of values of $\displaystyle x$ and $\displaystyle y$? Doesn't seem very efficient though..

Perhaps the forum should have a section on numerical analysis?

Thanks.