Math Is Fun Forum

Yes, the mistake in pirst proof is from the redians.

Please post a proof of k+28 Please! It must be more prime than mine!

Combined chess-domino question:
Prove that the chessboard with two opposite corners cutted cannot be overlayed with 31 same domino bricks. Each of the brick overlays exactly 2 chessboard cells.

hristo, where are you from?

1, 3, 6, 10, 15, 11, 5, 4, 12, 13, 23, 2, 7, 9, 16, 20, 29, 27, 22, 14, 35, 21, 28, 8, 31, 18, 38, 26, 30, 19, 17, 32, 24, 25, 39, 42, 58, 63, 37, 44, 56, 65, 79, 90, 54, 46, 75, 69, 52, 48, 33, 67, 77, 92, 104, 40, 41, 59, 62, 82, 87, 34, 47, 53, 68, 76, 45, 55
length=68!!!

1, 3, 6, 10, 15, 11, 5, 4, 12, 13, 23, 2, 7, 9, 16, 20, 29, 27, 22, 14, 35, 21, 28, 8, 31, 18, 38, 26, 30, 19, 17, 32, 24, 25, 39, 42, 58, 63
length=38

But there's infinity long sircular sequence!

Condition for existing line that divides grafhic of f(x) more than 2 times is that is nessesery to exist at least one inflex point.

Geometric proof:

Picture 6: The function we've iust assembled.

Picture 4: sinr(x)=sin(Pi x)