+0  
 
0
42
2
avatar

Let a_1, a_2, ..., a_n be real numbers such that a_1 + 2a_2 + ... + na_n = 1.  Find the minimum value of a_1^2 + 2a_2^2 + ... + na_n^2.

 Aug 13, 2021
 #2
avatar
0

By Cauchy-Schwarz, the minimum value is 1/n.

 Aug 14, 2021

35 Online Users