The website said that your 2.6 homework is due today, but I want
to collect it next time. Please hang on to it, and I'm sorry if
you rushed to get it done. I want to do the example of the
Euclidean algorithm for gcd before you do the relevant homework.
The curve: add 7 to your score, and compute your percentage out of 70
Comments
You should have arrived at a column all true, to prove the
theorem. The part below was to give you a context (or
interpretation) to understand why it worked.
The key offers two ways of proving this -- directly, or by
changing the consequent to make it more useful (e.g. deduction method).
The wff is invalid, as well explained by two of
us. writing the statements out was a little tricky! And of
course if you decided it was valid and tried to prove it, you
were up against a wall....
A fairly straightforward deduction method; but Chris did
it by temporary hypothesis.
Mate did a very thorough case analysis, and Bingchen tried
a really nice induction that impressed me.
A straighforward induction. Only a few forgot the base
case.
Those palindromes again -- tut tut! But this time with
only even numbers of 0s. Some of you seemed to ignore that part....
Then there was a realistic example of how Fibonacci numbers
occur, as family trees of bees.