Homework Help: Converting Spherical to Cartesian

Your equation is equivalent to [itex]\rho[/itex] = cos([itex]\phi[/itex])/(1 - cos²([itex]\phi[/itex]).

Your relevant equations show the converstion from spherical to Cartesian coordinates. Do you know the conversions going in the other direction?

One trick that will be helpful is to multiply both sides by rho. This potentially adds a point (rho = 0) that might not be a solution of your original equation, so you should check whether this is already a solution of your equation.

 

As an intermediate step, look at what I have in my previous post. Use trig identities to get to what I showed, then go from there.

 

You're missing a factor of cos(phi) in the numerator on the right side.

 

OK. I didn't catch what you were doing.

Don't you mean (1 - cos^2(phi))?

 

It's probably helpful not to change the rho^2 on the left side just yet.

 

Let us decide whether nothing good comes out of it. Show us what you tried.

You have rho^2 = z/(1 - cos^2(phi))
What do you get when you multiply both sides by 1 - cos^2(phi)?

 

That's a very nice thing to say! Thank you!

 

csc(x) = 1/sin(x), cot(x) = cos(x)/sin(x)

Are those the ones you mean?

 

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