The length of one arch of sine curve is
.
Arc length of the curve
in the interval
is
.
Consider the curve is
.
Apply derivative on each side with respect to
.
.
Substitute
and
in
.
.
The length of one arch of cosine curve is
.
Arc length of the curve
in the interval
is
.
The curve is
.
Apply derivative on each side with respect to
.
.
Substitute
and
in
.
.
Substitute
.

Consider
.
Apply derivative on each side with respect to
.

If
then
.
If
then
.
Substitute allt he values in
.



Therefore, the length of one arch of sine curve is equal to the length of one arch of cosine curve.
\The length of one arch of sine curve is equal to the length of one arch of cosine curve.