Questions related to memory devices that help learners recall larger pieces of information, especially in the form of lists like characteristics, steps, stages, parts.

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1
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1answer
15 views

Index notation of tensors and mnemonics

I've been trying to learn to manipulate tensors but I've got probably too comfortable with all the matrices in my Linear Algebra course, that it gets really difficult beyond rank-3 tensors. So, ...
8
votes
2answers
150 views

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 ...
20
votes
12answers
3k views

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 ...
2
votes
2answers
69 views

What is the good way to remember the signs of the rotational matrix?

Recall rotational matrix in (x,y) is given by: $R = \begin{bmatrix} \cos(\theta) & -\sin(\theta) \\ \sin(\theta) & \cos(\theta) \end{bmatrix}$ For the life of me I cannot remember if the ...
10
votes
5answers
373 views

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 ...
2
votes
7answers
162 views

Remembering that $\sin^2(\theta) = 1/2 - 1/2\cos(2\theta)$?

How do you remember this for integrals? It doesn't seem obvious and I can never remember it when I come across it in integrals.
5
votes
9answers
250 views

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
votes
2answers
519 views

Are there examples of when the ILATE mnemonic for choosing factors when integrating by parts fails?

Is it possible in some cases that using the ILATE rule does not yield an explicit antiderivative but making another choice does yields one? If so, please give examples.
6
votes
3answers
583 views

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 ...
8
votes
5answers
602 views

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.
3
votes
4answers
319 views

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 ...
1
vote
0answers
105 views

Remembering numbers while performing calculations mentally

Specific question: how can I improve on mentally performing calculations like these : $$(78-59)\times23-8\%\times(270+130)$$ ...
1
vote
0answers
93 views

Mnemonic for centroid of a bounded region

The centroid of a region bounded by two curves is given by: $ \bar{x} = \frac{1}{A}\int_a^b{x\left[f(x)-g(x)\right]dx} $ $ \bar{y} = ...
1
vote
1answer
322 views

What makes this mnemonic device work for multiplication?

I stumbled across a mnemonic device related to multiplication, outlined on this wikipedia page. I see that it does work, but I'd like to know why. It works as follows (from the wikipedia page): ...
9
votes
8answers
780 views

“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 ...
45
votes
6answers
7k views

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 ...