Question

The parametric equation of the circle whose center is $(3,-5)$ and touches the $x-$ axis is

• A. $x=3+5\cos \theta ,y=-5-5\sin \theta$
• B. $x=3+5\cos \theta ,y=-5+5\sin \theta$
• C. $x=3+3\cos \theta ,y=-5+3\sin \theta$
• D. $x=3+5\cos \theta ,y=-5-5\sin \theta$

Answer 1

The correct option is B $x=3+5\cos \theta ,y=-5+5\sin \theta$

The distance between the $x-$axis and centre is the radius
$\therefore$ distance of $(3,-5)$ from the $x-$ axis is $=|-5|=5$units
So the parametric equation are
$x=3+5\cos \theta ,y=-5+5\sin \theta$