The function is
.
Linear approximation is
.
.
Differentiate on each side with respect to
.

Find the values of
and
.
.
.
\
Linear approximation at
is
.
Substitute
and
in linear approximation equation.

The corresponding linear approximation is
.
\
For accuracy within 0.1.
\
.gif\")
The middle curve is
,the upper and the lower curves are
and
.
So from the graph we can say that
is accurate within 0.1 when
.
\
The corresponding linear approximation is
.
.