(a) Find the curvature of a straight line.
\The parametric line equations with slope
is
and
.
Apply curvature formula:
.
Find the first and second derivatives with respect to
.
Consider
.




.
\
Consider
.




.
Substitute
,
,
and
in
.

.
The curvature at each point of a straight line is
.
(b) Find the curvature of a circle.
\The parametric equations of circle are
and
.
Apply curvature formula:
.
Find the first and second derivatives with respect to
.
Consider
.


.

.
\
Consider
.


.

.
Substitute
,
,
and
in
.






.
.
The curvature of any circle is
.
(a) The curvature of any straight line is
.
(b) The curvature of any circle is
.