The parametric equation is
and
.
(a)
\Consider
.
.
Consider
.
.
Trigonometric identity :
.

The curve equation
represents a circle equation with center at origin and radius of
units.
(b)
\The parametric equation is
and
.
Consider
.

.
Consider
.

.
Trigonometric identity :
.

The curve equation
represents a circle equation with center at
and radius of
units.
The center of the circle shifted from origin to
.
(c)
\The sine and cosine are interchanged.
\The parametric equation is
and
.
Consider
.
.
Consider
.
.
Trigonometric identity :
.

The curve equation
represents a circle equation with center at origin and radius of
units.
But the curve starts from
where the curve in (a) starts at
.
(a) The curve equation
represents a circle equation with center at origin and radius of
units.
(b) The curve equation
represents a circle equation with center at
and radius of
units.
The center of the circle shifted from origin to
.
(c) The curve starts from
where the curve in (a) starts at
.