Suppose that the point (rho, theta, phi)= (12, 2pi/3, 5pi/4) in spherical coordinates can be expressed as (x, y, z) in rectangular coordinates. Find x+z. I first found x by using the conversion method (r*sin(theta)cos(phi)= x ) I got -3(sqrt(6)). Then I found z using (z= r*cos(theta) ) and got -6. I added these to get a final answer of -3(sqrt(6)) - 6 but apparently this answer is wrong.

Question

Suppose that the point (rho, theta, phi)= (12, 2pi/3, 5pi/4) in spherical coordinates can be expressed as (x, y, z) in rectangular coordinates. Find x+z. I first found x by using the conversion method (r*sin(theta)cos(phi)= x )  I got -3(sqrt(6)). Then I found z using (z= r*cos(theta) ) and got -6. I added these to get a final answer of -3(sqrt(6)) - 6 but apparently this answer is wrong.

Damon · Answer

are you sure z is not r cos phi

in math theta is usually i the xy plane
x = r sin phi cos theta
y = r sin phi sin theta
z = r cos phi

In engineering and physics these conventions are often different, nut I suspect you should be using phi as the angle down from the z axis, not theta

Damon · Answer

http://mathworld.wolfram.com/SphericalCoordinates.html

Damon · Answer

Other than that - Good job !

Aryan · Answer

whats the answer?