Discussion of the second study group can go here! APL Overview

[ <<< session 1 | session 3 >>>]

This is a wiki post - feel free to edit to add links from the lesson or other useful info.

## Overview

- Basic math operators (continued)
- Divide sign: reciprocal (monadic); divided by (dyadic)
- Times sign: direction; times
- Magnitude and direction of complex numbers; the unit circle

- Star: exponential; power
- Compound interest and exponential functions
- Limits
- Euler’s identity

- Precedence

## Study session resources

- Study session video
- Study session notebook (pinned to where we left off)

## Video timeline - thank you @Daniel

#### 00:00 APL: a hintsight of a brilliant plan

#### 04:18 Get ready to continue our APL learning

####
07:44 times sign `backtick -`

and review of how to get bookmark of APL keyboard for Jupyter notebook

####
09:32 See how (Dyadic `x`

) times work and how (monadic `x`

) direction work with real numbers

####
12:20 How does (monadic `x`

) direction work with complex number

#### 16:26 Keyboard preferences

#### 18:53 What is complex number in complex plane?

####
22:24 what is `2 + 2i`

written in APL? `2j2`

? What does direction do? What is a unit circle? How to understand the direction of a complex number in terms of a unit circle

Images

#### 29:51 Learn magnitude

#### 34:34 Learn divide sign

#### 35:09 How to understand reciprocal in APL?

Images

#### 36:48 clean up the notebook

#### 38:16 Precedence

####
44:04 learn power sign `*`

: how does (monadic `*`

) exponential work? how does (dyadic `*`

) power work?

####
46:38 What is `e`

? How did Jeremy explain it step by step?

Images

####
53:07 What kids’ reaction to Jeremy’s explanations of `e`

, limit and infinity? How do we understand of `e`

?

####
55:14 Who is `e`

named after? Wha are the interesting/crazy things about `e`

?

####
56:55 How to get `e`

in APL? How to use power (Dyadic)?

#### 57:59 More discussion of the interpretation of eiπ+1=0 in terms of rotating on the unit circle

#### 1:00:31 How to display the operation precedence in APL?

Images