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continuous

Source: Romania District Olympiad 2013,grade XI(problem 4)

March 14, 2013
functionlimitcalculuscalculus computations

Problem Statement

Letf:RRf:\mathbb{R}\to \mathbb{R}be a monotone function. a) Prove thatff have side limits in each point x0R{{x}_{0}}\in \mathbb{R}. b) We define the function g:RRg:\mathbb{R}\to \mathbb{R}, g(x)=limtxf(t)g\left( x \right)=\underset{t\nearrow x}{\mathop{\lim }}\,f\left( t \right)( g(x)g\left( x \right) with limit at at left in xx). Prove that if the gg function is continuous, than the function ff is continuous.