elliptical reflector 10" diam, 3" depth, focus (0,0), vertex

[D.Sedra]

Please explain the answer to this problem: An elliptical reflector is 10 inches in diameter and 3 inches deep. A light source is at one focus (0,0), 3 inches from the vertex (-3,0). Find the location of the other focus.

 

[Deleted member 4993]

Re: An ellipse question

Please explain the answer to this problem: An elliptical reflector is 10 inches in diameter and 3 inches deep. A light source is at one focus (0,0), 3 inches from the vertex (-3,0). Find the location of the other focus.

Did they provide a drawing with this?

Other wise

you have three points on the ellipse. (0, ±5) and vertex at (-3,0). One focus co-ordinate is given. How does that (the x-co-ordinate) relate to other parameters of the ellipse?

Please show us your work/thought so that we know where to begin to help you.

 

[D.Sedra]

Re: An ellipse question

Yes, there was a drawing. The three coordinates you mentioned are right. My idea would be to try to find the endpoints of the minor axis or the center of the ellipse. How would I do that?

 

[tkhunny]

Re: An ellipse question

Isn't the other Vertex and (7,0), making the other focus at (4,0), making the center of the ellipse at (2,0)?

Unless I have imagined the wrong drawing, these should be the first things on your list of things to identify. You're nearly done.

Note: What do "diameter" and "deep" mean for an ellipse? The drawing MUST be provided in order for the question to be reasonsble.