# Math Help - limit proof

1. ## limit proof

I'm sure the proof is really easy, but I am relatively new to these proofs and I'm not really sure how to start...

Let f: R $\rightarrow$ R and let c $\in$ R. Show lim as x $\rightarrow$ c of f(x) = L if and only if lim x $\rightarrow$ 0 of f(x+c) = L

(sorry about the code, this is the first time I have used Latex...can anyone suggest an all in one reference for Latex coding?)

2. Originally Posted by davido
Let f: R $\rightarrow$ R and let c $\in$ R. Show lim as x $\rightarrow$ c of f(x) = L if and only if lim x $\rightarrow$ 0 of f(x+c) = L
From the given $\left| {y - c} \right| < \delta \Rightarrow \quad \left| {f(y) - L} \right| < \varepsilon$.
Let $(x+c)=y$.
$\left| x \right| < \delta \Rightarrow \quad \left| {y - c} \right| = \left| {\left( {x + c} \right) - c} \right| = \left| x \right| < \delta \Rightarrow \quad \left| {f(x + c) - L} \right| = \left| {f(y) - L} \right| < \varepsilon$