Question

What are the foci of the ellipse? Graph the ellipse.

18x2 + 36y2 = 648

Answer 1

@genius12

Answer 2

@jim_thompson5910 @Directrix @.Sam. @Luis_Rivera can anybody help me please

Answer 3

@Hero

Answer 4

If you divide both sides by 648, you get the following:

1/36x^2 + 1/18y^2 = 1

The foci are at 3sqrt(2) and -3sqrt(2)

Answer 5

I did.

Answer 6

@genius12 Is it +- first or 0

Answer 7

This is what i mean because i know its between those to.

Answer 8

@genius12 Help please

Answer 9

because x^2 has the bigger denominator, the foci lie along the x-axis

Answer 10

What do you mean? The foci are achieved through his equation:

\[a^2-c^2=b^2\] Where a^2 in this is case is 36, c^2 we need to solve for, and b^2 is 18. This gives:

\[36-c^2=18\rightarrow c = \pm \sqrt18=\pm 3\sqrt2\]

Answer 11

I got my foci already. It's between 2 answers that i posted above. Do you know which one ?

Answer 12

The first one.

Answer 13

Thank you @genius12 :)