SOLUTION: Give a geometric description of the following problem: {{{ x^2 + y^2 + z^2 = 4 }}}, {{{ y = x }}} ----------- ---- I know that it is some kind of a sphere. But the {{{ y = x }

Algebra ->  Bodies-in-space -> SOLUTION: Give a geometric description of the following problem: {{{ x^2 + y^2 + z^2 = 4 }}}, {{{ y = x }}} ----------- ---- I know that it is some kind of a sphere. But the {{{ y = x }      Log On


   



Question 1034727: Give a geometric description of the following problem:
+x%5E2+%2B+y%5E2+%2B+z%5E2+=+4+, +y+=+x+
----------------
I know that it is some kind of a sphere. But the +y+=+x+ part is throwing me off.
Thank you!

Found 2 solutions by addingup, ikleyn:
Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
I don't know if I'm reading this correctly, but if y=x then:
+x%5E2+%2B+y%5E2+%2B+z%5E2+=+4+, +y+=+x+ = 2x%5E2+%2B+z%5E2+=+4
Assuming I'm interpreting this correctly, you have an ellipse:

Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
Give a geometric description of the following problem:
+x%5E2+%2B+y%5E2+%2B+z%5E2+=+4+, +y+=+x+
----------------
I know that it is some kind of a sphere. But the +y+=+x+ part is throwing me off.
Thank you!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`

First equation describes the sphere in 3D of the radius 2 with the center at the origin of the coordinate system.

The second equation describes the plane in the same 3D space. It passes through the origin of the coordinate system and contains the axis z.

Together, they describe the section of the sphere by the plane (their common points), which is a circle. It is a diametric section of the sphere.