00:01
We have a very old problem in which we're trying to place a certain number of grains of wheat on a chessboard.
00:05
There are 64 total spots on the chess board that we need to place wheat on.
00:10
The first spot will have one grain.
00:13
The second spot will have two.
00:15
The third spot will have four.
00:17
The fourth spot will have eight and so on forever, all the way up to the 64.
00:22
How many total grains of wheat do we need to place on this board? well, we can model this as a sequence.
00:29
So the first term is obviously going to be 1, and then the common ratio, that's going to be 8 over 4, or 4 over 2, or 2 over 1, which is just equal to 2 in any case.
00:43
I did multiple different terms just to prove that it's the same, no matter which two terms you pick.
00:48
So we have times 2 to the n minus 1.
00:51
And this is the basic form of a geometric sequence, as given in the book...