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#1 Re: Help Me ! » Test Question » 2007-06-13 21:39:48

If the rectangle exists, the values that cancel the area are " forbidden".
Then

#2 Re: Help Me ! » Test Question » 2007-06-13 01:04:59

C)possible values for k


(although strictly speaking 0 is not a forbidden value for k)
What do you think?

#4 Re: Help Me ! » Test Question » 2007-06-12 20:36:28

a) The coordinates of C are:
(k ; 16-k^2)
The coordinates of D are:
(-k ; 16-k^2)

#5 Guestbook » MathisFun » 2007-06-12 11:44:58

octonion
Replies: 4

This website is great, congratulations, from Paris, France.

#6 Re: Help Me ! » ellipse » 2007-06-12 10:39:24

Now I agree! and as we say in my country, merci...

#7 Re: Help Me ! » ellipse » 2007-06-12 09:11:40

JaneFairfax, thanks for your  help. I have a question though: how can you get only positive terms inside the square root, even after simplification, when you have negative terms? I did expand and simplify several times, and I get a     


term!!
This is driving me mad!

#8 Help Me ! » ellipse » 2007-06-11 01:53:53

octonion
Replies: 7

the sum of the distances from the point (x,y) on an ellipse to the points (-e,0) and (e,0) (where e>0) is constant and equal to S. Use this characterization of the ellipse to show that its equation in the xy-plane is x^2/a^2  + y^2/b^2 = 1, where a^2 = (S/2)^2 and b^2 = (S/2)^2 - e^2


I am using the vector form for the 2 distances, and I get S^2 = 4(x^2) + 4(y^2)
where did I go wrong?

Thanks to all for your help!

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