1. ## 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.)

2. ## 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?

5. ## 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.

6. ## 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?

7. ## Re: Need help please, need very quickly

The empty grid was all that came with the problem- im guessing there are no constraints.

8. ## Re: Need help please, need very quickly

Hi Makavell, did you solve the 4th question?

9. ## 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.

10. ## Re: Need help please, need very quickly

Mark, how would a basic proof of that look? Thanks