00:01
Okay, so we want to use mathematical induction to show that the following is true.
00:05
So let's start with n is equal to 1.
00:07
Well, that's equal to 1 times 1 plus 1 times 1 plus 2.
00:12
So that's 2 times 3, which is 6.
00:14
So 6 is divisible by 6.
00:16
So this is true.
00:18
And now let's move on to condition 2.
00:21
So in condition 2, we want to assume that n is equal to k is true.
00:27
That is k times k plus 1 times k.
00:31
Plus 2 is divisible by 6.
00:38
And now using this, we want to show that n is equal to k plus 1.
00:41
It's true.
00:42
So let's write out k plus 1.
00:44
This is k plus 1 times a k plus 2 and then a k plus 3.
00:56
So let's see.
00:58
So we want to rewrite it in this form, our current equation, because we know that this portion is divisible by 6.
01:05
So we have a k plus 1 and a k plus 2 in common.
01:08
So let's rewrite this, so it has a k that we can factor out.
01:12
So that means, let's see, how should we do this? let's write out this k plus 1 and a k plus 2.
01:23
And how do i factor out a k? maybe it's best if we just multiply everything out...