september 12 Lec 3
one of the best lectures so far!
The main topic today's lecture was how to look at a problem before starting to try and solve it, which I honestly have to admit I thought to myself '' well, everybody knows what these steps are'' but is wasn't that long after it that I found out I was wrong!
Lets see what these steps are that we often think we know until we begin solving a problem:
- Always write down what informations the question has given you and what it need you to prove and figure out
- Try to relate this to another problem you might have solved or seen! Try to relate them for as it can give you goo ideas
- Sometimes it's a big help to just take the problem apart! Look at the smaller parts and try to solve the puzzle one piece at a time
- Instead of going from assumption to resolution, look at the problem the other way around! It might seem weird but it can be a good start on solving the problem
Then we got this interesting question which I honestly enjoyed solving(the streetcar conversation**)
I'll go threw what I was thinking real quick
- The product of the kids ages is 36 so k1*k2*k3=36
- The conversation is telling me the sum of their age can't "directly" help me figure the ages out
- Some how knowing that there exists an eldest kid who plays the piano is supposed to help me guess
well it looks like the sum of their age did not help! why is that? lets take a look
lets right down all the factors of 36 and call the set A:
{1,2,3,4,6,9,12,18,36}
Now lets see what the ages can be:
(1,1,36) (1,2,18) (1,3,12) (1,4,9) (2,3,6) (2,2,9)! (3,3,4) (6,6,1)!
As you see only sum of the two sets with (!) are the same that's knowing that didn't help us at first but now that we have there is an eldest son, (1,6,6) is out of the picture so the ages are 2,2 and 9!
** please comment if you do not know what the question is so I can write it for you.
