Suppose the curve has the vector equation
,
, or, equivalently, the parametric equations
, where
are continuous.
If the curve is traversed exactly once as t increases from a to b, then it can be shown that its length is
.
The curve is
and the interval is
.
Consider
.
Differentiate the curve with respect to
.
.
Consider
.
Differentiate the curve with respect to
.
.
Consider
.
Differentiate the curve with respect to
.
.
Length of the curve
over the interval
is

Let
, then
.
Evaluating boundaries :
\At
,
.
At
,
.
Substitute corresponding values in
.

Apply formula :
.

Length of the curve
over the interval
is
.