2x^2 + 2y^2 + x + y = 0

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- Jun 17th 2009, 07:49 AMJoker37Sketch the graph of the following:
2x^2 + 2y^2 + x + y = 0

Show complete working out. - Jun 17th 2009, 08:30 AMHallsofIvy
Your question is not at all clear. You

**could**"sketch" the graph by calculating several points: if x= 0, so y= 0 or -1/2. and are points on the graph. Taking y= 0, we get, in exactly the same way, which we had before, . Get enough points that way and you can sketch the graph.

But I suspect that you are intended to**complete the square**to see what kind of figure this is:

If you divide through by 2 you get . Presumably you know that . Comparing that to , they match if a= 1/4 and we can make this a "perfect square by adding . Doing that for both x and y, or . What kind of figure is that? - Jun 17th 2009, 10:52 AMRachel.F
- Jun 17th 2009, 06:07 PMStroodle

Which is a circle with it's centre at with a radius of