Processing math: 100%
 
+0  
 
+1
901
3
avatar+159 

A nonzero polynomial with rational coefficients has all of the numbers 1+2,2+3,3+4,,1000+1001as roots. What is the smallest possible degree of such a polynomial?

 May 4, 2019
 #1
avatar+6252 
+1

The polynomial evaluated at 1 is the sum of the coefficients. This must be a rational numberThus each root that is not a rational number must have it's conjugate also as a rootThis will be all the roots of the form a+b where b{2,3,,1001}

 

There are 30 numbers in 2-1001 that are perfect squaresSo 100030=970 of the roots must also have their conjugate as a rootThus we have a total of 30+2970=1970 is the smallest possible degree of the polynomial

 

I'm pretty sure this is correct but I might be missing something.  Someone else should take a look.

 May 4, 2019
 #2
avatar+33657 
0

Your reasoning looks good to me!

Alan  May 5, 2019
 #3
avatar+159 
0

Thanks I understand now

 

It took me awhile

 May 12, 2019

2 Online Users