# Question: if a and b are n x n matrices such...

###### Question details

If A and B are n x n matrices such that AB = BA, show that .

To prove this you can use the Binomial Formula which states that if then .

Note that if a series in a complete normed vector space converges ABSOLUTELY (like the matrix exponential), the terms in the series can be arbitrarily rearranged without changing the limit.