Answer
Circular cylinder with radius $2$ and axis the z-axis
Work Step by Step
Here, we have $r=2$
In the cylindrical coordinate system, we have $x=r \cos \theta \\ y=r \sin \theta \\z=z$
Conversion of rectangular to cylindrical coordinate system, we have $r^2=x^2+y^2 \\ \tan \theta=\dfrac{y}{x} \\z=z$
Then, we have $\sqrt{x^2+y^2}=2$
Re-arrange as: $x^2+y^2=2^2$
Hence, we have an equation of a circular cylinder with radius $2$ and axis the $z$-axis.
