perplexus.info :: Numbers : Sum Square Grid Row & Column ≠ 0

Sum Square Grid Row & Column ≠ 0 (Posted on 2010-04-29)

Each cell of a 1997x1997 square grid contains either +1 or -1, with no cell being vacant.

The product of all the numbers in the ith row, and the product of all the numbers in the ith column are respectively denoted by R_i and C_i.

1997
Prove that Σ_i=1(R_i + C_i) is always nonzero.

See The Solution Submitted by K Sengupta

Rating: 3.0000 (3 votes)

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
re(2): Solution - (MS Word Formatting!?)	Charlie	2010-04-30 02:17:37
re(2): a simple proof NOW FOR THE PRODUCT	Ady TZIDON	2010-04-29 17:25:25
re: a simple proof	Daniel	2010-04-29 15:29:54
a simple proof	Ady TZIDON	2010-04-29 12:31:12
re: Solution - (MS Word Formatting!?)	farcear	2010-04-29 12:23:46
Solution	farcear	2010-04-29 12:18:11

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