Questions related to memory devices that help learners recall larger pieces of information, especially in the form of lists like characteristics, steps, stages, parts.
Questions tagged [mnemonic]
41 questions
113
votes
9 answers
What are Some Tricks to Remember Fatou's Lemma?
For a sequence of non-negative measurable functions $f_n$, Fatou's lemma is a statement about the inequality
$$\int \liminf_{n\rightarrow \infty} f_n \mathrm{d}\mu \leq \liminf_{n\rightarrow \infty}(\int f_n \mathrm{d} \mu)$$
or alternatively (for…
Learner
- 7,538
67
votes
12 answers
Easy way of memorizing values of sine, cosine, and tangent
My math professor recently told us that she wanted us to be able to answer $\sin\left(\frac{\pi }{2}\right)$ in our head on the snap. I know I can simply memorize the table for the test by this Friday, but I may likely forget them after the test. So…
James Smith
- 1,779
24
votes
6 answers
Injection vs. Surjection: Mnemonic to remember which is which
What are some mnemonics to help one remember that Injection = One-to-one and Surjection = Onto? The only thing I can think of is 1njection = 1-1.
user46234
20
votes
7 answers
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 {\alpha+\beta}{2}\, \cos \dfrac {\alpha-\beta}{2}…
Sebastiano
- 8,290
17
votes
2 answers
Easy way of memorizing or quickly deriving summation formulas
My math professor recently told us that she wants us to be familiar with summation notation. She says we have to have it mastered because we are starting integration next week. She gave us a bunch of formulas to memorize. I know I can simply…
James Smith
- 1,779
15
votes
7 answers
How to remember which function is concave and which one is convex?
I always struggle to remember when a function is convex and concave:
Do you have a particular trick to help you remember this?
My trick is based on the Spanish phrase "No cabe", pronounced nô ˈka.βe, which sound just like "concave". "No cabe"…
luchonacho
- 483
- 1
- 4
- 19
15
votes
5 answers
How to remember trig identities?
Suppose I have a trig function $T: \Bbb{R} \rightarrow \Bbb{R}$. I want to be able to derive four basic properties:
$$T(x) \cdot T(y)$$
$$T(x) + T(y)$$
$$T(x+y)$$
$$T(cx)$$
where $c$ is some scalar.
I know there are a bunch of identities:…
Stan Shunpike
- 5,293
- 4
- 43
- 81
12
votes
5 answers
Top 10 math mnemonics
If you study undergraduate medicine, mnemonics are almost indispensable - there is so much factual material to learn. I was never given any mnemonics in my time as a maths undegraduate. But Robert Israel just mentioned "iciacids" to help remember…
almagest
- 18,650
10
votes
8 answers
"How I wish I could calculate pi" analogs...
You might know the mnemonic for $\pi$ in the title or even this more elaborated one:
Sir, I bear a rhyme excelling
In mystic force, and magic spelling
Celestial sprites elucidate
All my own striving can't relate
Or locate they who can…
draks ...
- 18,755
10
votes
4 answers
How to remember sum to product and product to sum trigonometric formulas?
They are:
\begin{align}
\cos(a)\cos(b)&=\frac{1}{2}\Big(\cos(a+b)+\cos(a-b)\Big) \\[2ex]
\sin(a)\sin(b)&=\frac{1}{2}\Big(\cos(a-b)-\cos(a+b)\Big) \\[2ex]
\sin(a)\cos(b)&=\frac{1}{2}\Big(\sin(a+b)+\sin(a-b)\Big)…
Richard Smith
- 787
8
votes
2 answers
Am I the only one constantly forgetting the Eisenstein criterion?
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.
roi_saumon
- 4,406
7
votes
3 answers
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 (for differentiation), but this isn't very…
user547493
6
votes
4 answers
How to remember a particular class of trig identities.
Please how can I easily remember the following trig identities:
$$
\sin(\;\pi-x)=\phantom{-}\sin x\quad \color{red}{\text{ and }}\quad \cos(\;\pi-x)=-\cos x\\
\sin(\;\pi+x)=-\sin x\quad \color{red}{\text{ and }}\quad \cos(\;\pi+x)=-\cos…
user139919
- 63
6
votes
2 answers
Mnemonics for linear algebra
Sometimes formulas in linear algebra are not easy to remember. Some usefulness for the process of remembering can provide application of mnemonics.
Do you know some useful mnemonics for this purpose?
I'll give two examples:
For the process of…
Widawensen
- 8,517
6
votes
9 answers
Memorizing the identities $\cos {\pi \over 3}=\sin {\pi \over 6} = {1 \over 2}$
I memorized $\sin {\pi \over 4} = \cos {\pi \over 4}= {1\over \sqrt{2}}$ easily by using the diagonal inside the unit square.
I am having great trouble memorizing the identities $\cos {\pi \over 3}=\sin {\pi \over 6} = {1 \over 2}$ because I keep…
Anna
- 1,817