(6) (Bonus) Determine the Cartesian equation of the surface with spherical coordinate equation rho = 2 cos θ sin φ − 2 sin θ sin φ + 2 cos φ. It turns out this describes a sphere. What is the center and radius of this sphere?

Respuesta :

Answer:

Hence, the sphere has a radius of [tex]\sqrt{3}[/tex]  and is centered at the point (1,-1,1)

Step-by-step explanation:

We have the equation

[tex]\rho=2cos\theta cos\phi-2sin\theta sin\phi+2cos\phi[/tex]

We have to take into account the relation between coordinates

[tex]\rho=\sqrt{x^2+y^2+z^2}\\x=\rho cos\theta sin\phi\\y=\rho sin\theta sin\phi\\z= \rho cos\phi[/tex]

by substituting we have:

[tex]\rho=2[\frac{x}{\rho}-\frac{y}{\rho}+\frac{z}{\rho}]\\\\\rho^2=2x-2y+2z\\\\x^2+y^2+z^2=2x-2y+2z[/tex]

We have to complete squares:

[tex](x^2-2x+1)+(y^2+2y+1)+(z^2-2z+1)-1-1-1=0\\\\(x-1)^2+(y+1)^2+(z-1)^2=3[/tex]

Hence, the sphere has a radius of [tex]\sqrt{3}[/tex]  and is centered at the point (1,-1,1)

hope this helps!!