Proof by induction is a proof technique used to establish a given statement for all natural numbers. It is similar to the idea of dominoes, in which by knowing that domino0(d0) works, I know that d1 works, then d2, then d3 and so on until all dominoes (all natural numbers) have been enumerated. The general structure for proof by induction goes like this:
1. Assume d0 does fall
2. Base case: d0 falls # by assumption
3. Induction step: - assume n a generic natural number, and that dn falls
- then dn+1 falls # dn will hit dn+1
- then for all n, dn falls implies dn+1 falls
- then for all n, dn falls
- then d0 falls implies for all n, dn falls
Basically, the central idea is that after proving that the base case works, assume the assumption works for dn, and try to arrive at a conclusion that dn+1 also works.
Here is an example of proof by induction, (without the quantifiers and bookends):
claim:
proof:
Lastly, proof by induction is a topic that comes easy to me since I already learned it before. However, the problem about diagonals presented in class troubles me. I was unable to figure out a clear pattern to the boxes since there are too many different combinations of dimensions for the box. Thanks to Loora's blog, I was able to gain some insight.
http://looralicsc165slog.blogspot.ca/2014/11/last-problem-solving.html?showComment=1417589892018#c163994337424380139

This helps me understand better on proof by induction! Thx!!
ReplyDeletewelcome! glad it helped!
DeleteThe steps are so clear. Love this!
ReplyDeleteYour example is clear and concise, nicely done. Also, I really like the comparison you made between proof by induction and dominoes; it instantly clarifies some possible confusion of how a proof for n and n+1 can lead to a proof for every natural number. Lastly, my friend and I were able to come up with something for the diagonal problem. Check out my slog at http://kenguoslog165.blogspot.com/2014_12_01_archive.html if you are interested.
ReplyDelete