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equation of a sphere
i have to show this equation represents a sphere..
but i'm stuck on the z variable as it won't come down to an even square. it comes down to a (x+2)(x-2).
Note that x^2 - 8x = (x - 4)^2 - 16 and y^2 + 4y = (y + 2)^2 - 4.Originally Posted by greencheeseca
i have to show this equation represents a sphere..
but i'm stuck on the z variable as it won't come down to an even square. it comes down to a (x+2)(x-2).
1. The general equation of a sphere with the centeri have to show this equation represents a sphere..
but i'm stuck on the z variable as it won't come down to an even square. it comes down to a (x+2)(x-2).and the radius r is
2. Transform your equation until it has the form of the general equation:
Completing the square(s):
3. I'll leave the rest for you.
i have to show this equation represents a sphere..
but i'm stuck on the z variable as it won't come down to an even square. it comes down to a (x+2)(x-2).The only term with z in it is z^2 and I don't see what your problem could be with it. I have already shown you how to deal with the x-terms and y-terms.
You apparently are trying to do this asi have to show this equation represents a sphere..
but i'm stuck on the z variable as it won't come down to an even square. it comes down to a (x+2)(x-2).
which is wrong for two reasons. First, moving that "- 4" to the other side of the equation makes it "" which cannot be factored, not "
".
But you don't want to do that to begin with!
Instead leave that constant, 4, on the right and do it as
Complete the square in x and y. The "z" term is already a perfect square! The numbers you need to add on the left to make the perfect squares, and, of course, add on the right, will give you a positive number on the right.
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