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## #1 2011-06-09 04:47:27

MathPro101
Member
Registered: 2011-06-08
Posts: 18

### Complex Equation

I found this video on youtube of an MIT Physics lecture. If you jump ahead to around 45 minutes, the professor offers a math problem that I found interesting.

It took me a long time to work through it, but if you know the trick, it can be solved in less than 10 seconds.

i^i, where i = sqrt(-1)

the clue is that i=e^i(pi/2 plusminus 2*pi*n), n=0,1,2,...

Have fun with it, let me know what you think.

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## #2 2011-06-18 02:40:07

soroban
Member
Registered: 2007-03-09
Posts: 452

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## #3 2011-06-18 05:54:56

MathPro101
Member
Registered: 2011-06-08
Posts: 18

### Re: Complex Equation

Very Good! One quick addition to that would be to say that θ = π/2 ± 2πn, where n=0,1,2,.. This is the same as rotating on the unit circle and getting back to the same place each time. Therefore the true answer should be e^(-π/2 ± 2πn), which is still a real number!

There is another way of solving this problem that uses a different technique. Can anyone figure that one out? It simplifies things greatly.

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