Ellipsoid
All squared, all positive, equals 1
Hyperboloid of One Sheet
All squared, ONE negative, equals 1 (on negative’s axis)
Hyperboloid of Two Sheets
All squared, TWO negatives, equals 1
Elliptic Cone
All squared, ONE negative, equals zero
Elliptic Paraboloid
TWO squared, all positive, equals non-squared variable
Hyperbolic Paraboloid
TWO squared, ONE squared negative, equal to non-squared variable
Rectangular/Cartesian coordinates
(x, y, z)
Cylindrical coordinates
(r, θ, z)
r = radius/distance from origin (xy axis, 2D)
θ = angle
z = height
Spherical coordinates
( p, θ, Φ)
p = distance from origin (3D)
θ = angle
Φ = angle from z-axis
find x (cylindrical to rectangular)
r cosθ
find y (cylindrical to rectangular)
r sinθ
find z (cylindrical or rectangular)
z
find r (rectangular to cylindrical)
sqrt(x² + y²)
find θ (rectangular to cylindrical)
tan-1 (y/x)
find x (spherical to rectangular)
p sinΦ cosTHETA
find y (spherical to rectangular)
p sinΦ sinTHETA
find z (spherical to rectangular)
p cos Φ
find p (rectangular to spherical)
sqrt (x² + y² + z²)
find Φ (rectangular to spherical)
cos-1 (z/ sqrt(x² + y² + z²) )
find p (cylindrical to spherical)
r / sinTHETA
find r (spherical to cylindrical)
p sinΦ
find r (spherical to cylindrical)
p sinΦ
find z (spherical to cylindrical)
p cosΦ
what shape?
p = n
sphere
what shape?
THETA = pi/n
plane orthogonal to xy plane going through origin
what shape?
Φ = pi/n
elliptic cone (half)
what shape?
Φ = +— pi/n
elliptic cone (full)
what shape?
r = n
right circular cylinder (toilet paper roll)
what shape?
z = n
plane parallel to xy plane, up n units