How many ways can we get 2 a's and 2 b's from aabb?
Because abab is the same as aabb. I was how to solve these problems with the blank slot method, i.e. _ _ _ _. If I do this manually, it's clear to me the answer is 6, aabb abab abba …
Matrices - Conditions for $AB+BA=0$ - Mathematics Stack Exchange
There must be something missing since taking $B$ to be the zero matrix will work for any $A$.
elementary number theory - Divisibility Tests for Palindromes ...
I've found and proven the following extensions to palindromes of the usual divisibility rules for 3 and 9: A palindrome is divisible by 27 if and only if its digit sum is. A palindrome is divisible by …
11 | abba, where a and b are the digits in a 4 digit number.
Nov 21, 2013 · Truly lost here, I know abba could look anything like 1221 or even 9999. However how do I prove 11 divides all of the possiblities?
sequences and series - The Perfect Sharing Algorithm (ABBABAAB ...
Oct 4, 2016 · The algorithm is normally created by taking AB, then inverting each 2-state 'digit' and sticking it on the end (ABBA). You then take this entire sequence and repeat the process …
How to calculate total combinations for AABB and ABBB sets?
Apr 19, 2022 · Although both belong to a much broad combination of N=2 and n=4 (AAAA, ABBA, BBBB...), where order matters and repetition is allowed, both can be rearranged in different …
$A,B$ be Hermitian.Is this true that $tr[(AB)^2]\\le tr(A^2B^2)$?
May 29, 2015 · @user1551 it feels like there should be a simpler justification, but I'll settle for the quick and dirty explanation.
How do we prove that $a^ {\log {b}} = b^ {\log {a}}$ for $a > 1
I have tried using the change of base formula, but can't quite complete the equality: $$ a^{\\log{b}} \\\\ a^{\\frac{\\log_a{b}}{\\log_a{a}}} $$ How do I get the base of the exponent to be b?
random variables - probability of playing music player on shuffle …
1.How many sequences of 4 songs are there where no song plays twice in a row? If we label the songs {A, B, C, D}, then examples are ABCD and ABAB but not ABBA. For this problem I just …
Uncountable vs Countable Infinity - Mathematics Stack Exchange
My friend and I were discussing infinity and stuff about it and ran into some disagreements regarding countable and uncountable infinity. As far as I understand, the list of all natural …