What is the Error in Calculating (e^(iπ))^i?

  • Context: High School 
  • Thread starter Thread starter Anonymous Vegetable
  • Start date Start date
  • Tags Tags
    Euler Identity
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
14 replies · 2K views
Anonymous Vegetable
Messages
33
Reaction score
0
Before I start, there are only really two pieces of information this concerns and that is the idea that 1x = 1 and that ei*π = -1

So it would follow that (ei*π)i = -1i
And so that would mean that i2i = e which doesn't seem to be right at all. Where is the issue here as there must be one but I am sure I don't have the knowledge required to figure it out.
 
Physics news on Phys.org
Bystander said:
Re-investigate this aspect.
I've edited it to make another point anyway hahaha but yeah I shall
 
Bystander said:
Point of order: please do NOT make changes to your original post. It makes very confusing reading for late arriving participants.
My humbumblest apologies and it shan't happen again.
 
Not all exponentiation laws work with complex numbers, and with a complex base those exponents are not unique any more.

$$i^{2i} = e^{2i \log(i)} = e^{2i (i \pi/2)} = e^{- \pi}$$ using the principal value of the logarithm, indeed.
 
I just find it amusing that what appears to be an extremely non real value seems to equal a simple real number
 
mfb said:
Not all exponentiation laws work with complex numbers, and with a complex base those exponents are not unique any more.

$$i^{2i} = e^{2i \log(i)} = e^{2i (i \pi/2)} = e^{- \pi}$$ using the principal value of the logarithm, indeed.
I assume your log refers to ln? Sorry just being picky
 
micromass said:
Outside of high school, logarithms with base ##e## are always denoted as ##\log##. The notation ln is not really used anymore.
I don't believe that's true. Every calculus textbook I have distinguishes between log (meaning base-10 logarithm) and ln. Granted, all of my textbooks are at least 15 to 20 years, and some are older.
 
  • Like
Likes   Reactions: weirdoguy
Mark44 said:
micromass said:
Outside of high school, logarithms with base ##e## are always denoted as ##\log##. The notation ln is not really used anymore.
I don't believe that's true. Every calculus textbook I have distinguishes between log (meaning base-10 logarithm) and ln. Granted, all of my textbooks are at least 15 to 20 years, and some are older.
I know it adds little to the conversation, but I have to concur. Pretty much all my textbooks use ln. Maybe it's an undergrad thing?
 
Anonymous Vegetable said:
So it would follow that (ei*π)i = -1i
And so that would mean that i2i = e-π which doesn't seem to be right at all. Where is the issue here as there must be one but I am sure I don't have the knowledge required to figure it out.
What seems to be the problem? I don't see one.