Suppose functions f,g : (a,b) -> R are continuous, and f(r) = g(r) for each rational number r in (a,b). Show that f(x) = g(x) for each x element (a,b).

Assume f(x) not equal g(x) for some x0 element (a,b) and a<x0<b

Since both functions are continuous we have:

lim(xf) = x0 and limf(xf) = f(x0)

lim(xg) = x0 and limg(xg) = g(x0)

This must hold true for x0 = r since a<r<b. Then, f(r) = g(r).

I think i'm making some leap somewhere can anyone help me clarify what i'm trying to do if by chance it even remotely looks like anything good.

Thanks