
Why is $1/i$ equal to $-i$? - Mathematics Stack Exchange
May 11, 2015 · 11 There are multiple ways of writing out a given complex number, or a number in general. Usually we reduce things to the "simplest" terms for display -- saying $0$ is a lot cleaner …
abstract algebra - Prove that 1+1=2 - Mathematics Stack Exchange
Jan 15, 2013 · Possible Duplicate: How do I convince someone that $1+1=2$ may not necessarily be true? I once read that some mathematicians provided a very length proof of $1+1=2$. Can you think …
Formal proof for $ (-1) \times (-1) = 1$ - Mathematics Stack Exchange
Jun 13, 2020 · Is there a formal proof for $(-1) \\times (-1) = 1$? It's a fundamental formula not only in arithmetic but also in the whole of math. Is there a proof for it or is it just assumed?
What is the value of $1^i$? - Mathematics Stack Exchange
Aug 30, 2010 · There are infinitely many possible values for $1^i$, corresponding to different branches of the complex logarithm. The confusing point here is that the formula $1^x = 1$ is not part of the …
Why is $1$ not a prime number? - Mathematics Stack Exchange
Jun 28, 2022 · 49 actually 1 was considered a prime number until the beginning of 20th century. Unique factorization was a driving force beneath its changing of status, since it's formulation is quickier if 1 is …
factorial - Why does 0! = 1? - Mathematics Stack Exchange
Intending on marking as accepted, because I'm no mathematician and this response makes sense to a commoner. However, I'm still curious why there is 1 way to permute 0 things, instead of 0 ways.
If $A A^{-1} = I$, does that automatically imply $A^{-1} A = I$?
Mar 30, 2020 · This is same as AA -1. It means that we first apply the A -1 transformation which will take as to some plane having different basis vectors. If we think what is the inverse of A -1 ? We are …
algebra precalculus - Prove $0! = 1$ from first principles ...
Feb 8, 2011 · How can I prove from first principles that $0!$ is equal to $1$?
General term formula of series 1/1 + 1/2 + 1/3 ... +1/n
This sum is called $H_n$ the $n$th"harmonic number" and has no known closed form.
power series - How can we know the answer to 1-1+1-1+1 ...
The series does not converge, because as you observe, the partial sums $1,0,1,0,\ldots$ oscillate and do not approach a single limit. There are various ways to assign values to some divergent series, …