# Need help please, need very quickly

• Oct 16th 2012, 07:47 PM
Makaveli
Need help please, need very quickly
An ordered quadruple (y₁,y₂,y₃,y₄) is quadratic if there exists realnumbers a, b, and c such that yn = an²+ bn + c
for n=1,2,3,4
Prove that if 16 numbers are placed in a 4x4 grid such that all four rows are quadratic
and the first three columns are also quadratic then the fourth column must also be quadratic.
(We say that a row is quadratic if its entries, in order, are quadratic. We say the same
for a column.)
• Oct 16th 2012, 08:54 PM
chiro
Re: Need help please, need very quickly
Hey Makaveli.

Can you explain this grid? If it's a matrix then you can write out the relationship between the cells and the constraints on those cells?
• Oct 16th 2012, 10:16 PM
kalwin
Re: Need help please, need very quickly
• Oct 17th 2012, 08:00 AM
Makaveli
Re: Need help please, need very quickly
• Oct 19th 2012, 12:41 PM
Makaveli
Re: Need help please, need very quickly
Could someone please figure this out and show me how they got the answer please? My test is on Sunday, I have to go into school to take it. Thanks so much.
• Oct 19th 2012, 02:42 PM
chiro
Re: Need help please, need very quickly
What is in the grid? You just posted an empty grid. What are the constraints of the cells in the grid?
• Oct 19th 2012, 06:43 PM
Makaveli
Re: Need help please, need very quickly
The empty grid was all that came with the problem- im guessing there are no constraints.
• Oct 19th 2012, 08:46 PM
zhi
Re: Need help please, need very quickly
Hi Makavell, did you solve the 4th question?
• Oct 19th 2012, 09:42 PM
MarkFL
Re: Need help please, need very quickly
The way I see it, given that all 4 rows are quadratic, and the first column is also quadratic, then it follows that the remaining 3 columns must also be quadratic.
• Oct 20th 2012, 04:57 PM
Makaveli
Re: Need help please, need very quickly
Mark, how would a basic proof of that look? Thanks
• Oct 20th 2012, 05:30 PM
skeeter
Re: Need help please, need very quickly