Recent content by delriofi

Hurray! Thanks errbody. You guyz are so smart!

Hahaha uhhh I guess the negative of 3.2, so -3.2 ? Good point. So because it's an ellipse then there are necessarily 2 points where dy/dx = 1 and so my answer should be like (4.5, -3.2) and (-4.5, 3.2) eh?

Oh ok no sorry... 9y^2/256 + y^2/16 = 1 so 25y^2/256 = 1 and thus 25y^2 = 256 so... y = sqrt (256/25) which is 3.2 apparently... Is that better?

So...y = 0.110679 ?

It would be... 81y^2/2304 I think?

So it would be 81y^2/256 ?

In response to jbunniii, is it -9y^2/16 or no is it -9y^2/16^2 ?

Is it -9y^2/16 ?

How do you solve (-16x/9)^2/9 ? That's some confusing algebra. I get -x^2/9 but that's wrong. What do you get?

Is it -y^2/16?

Ok so I did x^2/9 + (-9y/16)^2/16 = 1 and I get that x^2/9 - x^2/9 = 1 but that doesn't make sense does it?

I keep getting that x^2/9 - x^2/9 = 1 but that don't make sense does it?

I get x = -9y/16 and y = -16x/9. So I should just do... x^2/9 + (-16x/9)^2/16 = 1? Or is that wrong?

I used implicit differentiation, so it still should have worked.

I'm not sure what you mean... I haven't taken math in 4 years and now I have to learn calculus as a prerequisite so there's probably something really obvious that I should already know but don't. I differentiate that x^2/9 + y^2/16 = 1 has the derivative -16x/9y, and so if -16x/9y = 1 then...