\(\underrightarrow{x~\hbox{approaches 1 from the left}}\)
\(\underleftarrow{x~\hbox{approaches 1 from the right}}\)
\(x\)
\(0.9\)
\(0.09\)
\(0.999\)
\(\rightarrow\)
\(1\)
\(\leftarrow\)
\(1.001\)
\(1.01\)
\(1.1\)
\(f(x)=2x\)