I can not figure this problem out. Please somebody help me. let f: (a,b)$\displaystyle \rightarrow$R, where a,b $\displaystyle \in$R be a function and let x $\displaystyle \in$(a,b). Prove that if limh$\displaystyle \rightarrow$0|f(x+h)-f(x)|=0, then lim h$\displaystyle \rightarrow$0|f(x+h)-f(x-h)| = 0.