Questions tagged [mnemonic]
Questions related to memory devices that help learners recall larger pieces of information, especially in the form of lists like characteristics, steps, stages, parts.
41
questions
1
vote
0
answers
114
views
Is there a handy mnemonic or visual aid for all the basic set theory function relations, such as $f(A\cap B)\subseteq f(A)\cap f(B)$?
Glancing at Appendix A of John Lee's Introduction to Topological Manifolds, I noticed the following list of rules:
I'm familiar with rules like these and have no trouble proving them—that's not my ...
- 6,672
0
votes
0
answers
54
views
Has anyone heard of the "Of" operator, and if yes then what does it represent?
Where I studied (India), in my school we were taught BODMAS as Brackets, Of, Division, Multi, Add, Sub.
With "Of" being the Of operator as in
1/2 Of 4 ie. Literally - 1/2 parts of 4
Can ...
0
votes
0
answers
76
views
Mnemonics for memorizing $\overline{g:F(A)\to B}=G(g)\circ \eta_A$ and $\overline {f:A\to G(B)}=\epsilon_B\circ F(f)$
Let $F:\mathscr A\to \mathscr B$ be a left adjoint to $G:\mathscr B\to\mathscr A$. Write overline $(\overline {\circ})$ for the (either direction) of the bijection $$\mathscr B(F(A),B)\simeq \mathscr ...
- 12k
19
votes
7
answers
1k
views
The formulas of prostapheresis: memorization technique
This question is related purely for my students of an high school and indirectly for me. The formulas below are the formulas of prostapheresis,
\begin{cases}
\sin\alpha+\sin\beta=2\,\sin \dfrac {\...
- 7,792
4
votes
1
answer
472
views
Mnemonic to remembering that inverse limits are limits and direct limits are colimits
Sometime ago I had trouble remembering that right adjoints preserve limits (and so left adjoints preserve colimits). But ever since R. Vakil suggested that we use RAPL as a mnemonic to Right Adjoint ...
- 4,563
1
vote
3
answers
1k
views
How do you reverse a percentage change?
Is there any simple way to know how to reverse a percentage?
For example if I have 100 and it goes down by 10% I end up with 90. If I then add to it by 10% I end up with 99, not the 100 that you ...
- 153
4
votes
2
answers
573
views
What lies behind the definitions of split monics and epics?
Is there an easy way to memorize the definitions of split monics and split epics, and not to confuse the domains/codomains of the arrows from those definitions?
For example, is there a mnemonic rule?...
- 12k
0
votes
0
answers
117
views
Mnemonic for Remembering Epic vs Monic
I am trying to remember which arrows are epic (epimorphisms) and which arrows are monic (monomorphisms), but the terminology is very confusing. What is a hint/mnemonic for remembering which is which?
...
- 2,342
1
vote
2
answers
163
views
Is there a reason why we call $\mathrm{Hom}(A, -)$ covariant and $\mathrm{Hom}(-,B)$ contravariant?
I have trouble remembering what it means to apply the covariant or contravariant Hom functor.
For example, when I see $\mathrm{Hom}(A, -)$, I always forget if I am going to reverse arrows or not.
...
- 12.1k
1
vote
2
answers
108
views
What would be the best way to memorize the 10 by 10 multiplication table?
Hear me out before you start downvoting please. I have a learning disability so no matter how hard I try I can’t memorize the table. Please give some tips/hints on how to memorize the table. Thanks in ...
user649955
0
votes
1
answer
119
views
Mnemonic for cubic discriminant?
I sort of doubt there is a good one out there, but I thought I'd ask. I'm looking for a mnemonic for the general discriminant of the polynomial $ax^3+bx^2+cx+d$, which is
$$b^2c^2-4ac^3-4b^3d-27a^...
- 19.4k
8
votes
2
answers
1k
views
Am I the only one constantly forgetting the Eisenstein criterion? [closed]
Do you guys have tricks to remember the Eisenstein criterion? I constantly forget it and I am looking for some logic in it to never forget it again.
- 4,256
7
votes
3
answers
7k
views
Mnemonic for Integration by Parts formula?
The Integration by Parts formula may be stated as: $$\int uv' = uv - \int u'v.$$
I wonder if anyone has a clever mnemonic for the above formula.
What I often do is to derive it from the Product Rule ...
user547493
1
vote
0
answers
148
views
How to remember which is lower/upper semicontinuity?
There are several ways in which continuity can be formulated as two conditions - in a way such that one of them is lower semicontinuity and the other one is upper semicontinuity. (See below for ...
- 54.3k
2
votes
1
answer
300
views
Mnemonics for typical integrations
I am supposed to mug up these integrals for my upcoming exams:
$$\int\sqrt{a^2-x^2}dx=\frac{x}{2}\sqrt{a^2-x^2}+\frac{a^2}{2}\sin^{-1}\frac xa+C$$
$$\int\sqrt{x^2+a^2}dx=\frac{x}{2}\sqrt{x^2+a^2}+\...
- 6,479