Jan 26, 2026 · That is, there seems to be fairly strong symbolic evidence that for $n=4$, if $ABBA-BAAB = A-B$ and $A$ is nilpotent, then $B^4 = \lambda I$ for some $\lambda$.

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 ways: …

Jun 23, 2022 · Are you required to make it wiht polar transformation? Because with the change $x=uv$ $y=u (1-v)$ it's easier

Mar 18, 2026 · Q&A for people studying math at any level and professionals in related fields

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 thought the …

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 baba bbaa baab Which is …

The minimum number of states in min DFA of regular expression $(a+b)^*b(a+b)$ is _____. My attempt: I have drawn this DFA and found the answer to be 3: Somewhere it was explained that we need "trap"

There must be something missing since taking $B$ to be the zero matrix will work for any $A$.

I get the trick. Use the fact that matrices "commute under determinants". +1

How many 4 digit numbers are there whose decimal notation contains not more than two digits? Answer is 576. The question is very confusing. This is Arun Sharma CAT question.