Simple(?) conics question.. (1 Viewer)

[morgoe]

I'm probly missing something obvious.

You're asked to sketch (x^2/4) + (y^2/3) = 1

So the eccentricity comes to e=1/2

Then the foci are at (+-2, 0) which are the co-ordinates of the ends of the major axis? Is that possible? I thought the foci were always inside the ellipse. Am I missing something or is this alright?

 

[tommykins]

your eccentricity is wrong.

e = sqrt(16-9)/2 = sqrt7/2

 

[Affinity]

your eccentricity is wrong.

e = sqrt(16-9)/2 = sqrt7/2

Yours is wrong...

it's sqrt(4-3)/2 = 1/2

OP: foci are at (+/- 1,0)

 

[tommykins]

Yours is wrong...

it's sqrt(4-3)/2 = 1/2

OP: foci are at (+/- 1,0)

oh right, just did it in my head.

seems like i gotta review conics.

EDIT - oh i see where i went wrong, a^2 - b^2 , instead i squared a^2 to make a^4 ._.

 

[u-borat]

I'm probly missing something obvious.

You're asked to sketch (x^2/4) + (y^2/3) = 1

So the eccentricity comes to e=1/2

Then the foci are at (+-2, 0) which are the co-ordinates of the ends of the major axis? Is that possible? I thought the foci were always inside the ellipse. Am I missing something or is this alright?

yeah focus are ae, not a^2e, so its 2X 1/2 and 2X -1/2, not four.