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Proof that 4 = 3


Here is the proof that 4 = 3:

a + b = c
4a - 3a + 4b - 3b = 4c - 3c
4a + 4b - 4c = 3a + 3b - 3c
4(a + b - c) = 3(a + b - c)

Hence 4 = 3

As a trader, do you know algebra? Do you need to know it?

Before you read further in this thread/topic and see an explanation about the flaw in this "puzzle" you may want to try and work it out yourself. Let us know if you managed to solve it by yourself.
When traders tell me that I have the wrong or a different formula for calculating pivot points I often have to go through a process of re-arranging the pivot formula to show them that the formula that I am using is in fact the same as theirs but just arranged slightly differently.
quote:
Originally posted by day trading

Here is the proof that 4 = 3:

a + b = c
4a - 3a + 4b - 3b = 4c - 3c
4a + 4b - 4c = 3a + 3b - 3c
4(a + b - c) = 3(a + b - c)

Hence 4 = 3

As a trader, do you know algebra? Do you need to know it?


Very cute, Guy. Having been an algebra teacher in another life, I know the trick, and why this isn't a proof that 4 = 3, of course, but I'm not sure if you want it posted here, hence maybe defeating the purpose of forcing people to think about your point. If you didn't want this shown, just edit out this part:

Since a + b - c = 0 (by a simple rearrangement of the initial condition that a + b = c), you can't 'divide it out' of both sides in the last step there (you can't divide by zero), leaving 4 = 3. The fact that it equals zero is what allows the equality to remain true until that last step, since zero times any number will yield zero, and hence 4 * 0 = 3 * 0 (= 0). It is interesting, though, how easy it is to fool many people with a very nicely chosen example such as this one.

Now, how important is algebra? Well, I feel it was my advanced mathematical skills, all the way up to graduate level work, especially 'Probability Theory' and 'Game Theory', that gave me the foundation to create all the new material that I did for my methodology. Yes, I'm the old math teacher, so I'm expected to say that, but I feel math skills are crucial to the type of methodology I have. Some people, though, take other approaches and perhaps don't need all those skills, but it's a huge part of my work.

Hope I didn't mess up here, Guy, showing that :-)
You didn't mess up at all Jim. I was wondering how long it would take someone to come up with the correct explanation of the flaw in the logic. You explained the solution well.

I also agree with your comments about using advanced math skills in trading. It gives one a huge advantage to be able to work out probabilities of outcomes and hence the ability to dismiss or further investigate set-ups and strategies.
We seem to be on the same page just about every time I've talked with you. I'm hoping that's a good thing. I suspect so, but I'm pretty far out there...
Being far out there is were it's at!
Ex-act-ly.