Homework SourseSelect the statement that is TRUE about the surface describe
Select the statement that is TRUE about the surface described in cylindrical
coordinates by the equation r^2 + z^2 = 25?
(A) Is it a circle of radius 5 centered at the origin.
(B) Is it a cylinder of radius 5 centered at the origin.
(C) Is it a sphere of radius 5 centered at the origin.
(D) Is it the plane x + y + z = 5
coordinates by the equation r^2 + z^2 = 25?
(A) Is it a circle of radius 5 centered at the origin.
(B) Is it a cylinder of radius 5 centered at the origin.
(C) Is it a sphere of radius 5 centered at the origin.
(D) Is it the plane x + y + z = 5
Solution
c) it is sphere
as we know x=rcos ,y=rsin
x2+y2=r2cos2+r2sin2
x2+y2=r2
as co2s+sin2=1
substitute in your eqn
x2+y2+z2=52
this represent option (c)
