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Tuesday, April 14, 2020

Chromebook linux beta

Open Chrome OS developer shell  Ctrl + Alt + T
vmc list
vmc start termina 

check for default Linux container 
lxc list

If the penguin container is listed, you can try manually starting it 
logout
vmc container termina penguin

destroy a virtual machine

Sunday, April 12, 2020

Integration to sum

The definite integral of a continuous function $f$ over the interval $[a,b]$, denoted by $\int_a^b f(x) dx$, is the limit of a Riemann sum as the number of subdivisions approach infinity.
\[ \int_a^b f(x)dx = \lim_{n \to \infty} \sum_{i=1}^n \delta x \cdot f(x_i) \]
where $\delta x = (b-a)/n$, and $x_i = a+\delta x \cdot i$.

Example
\[\int_{\pi}^{2\pi} cos(x)dx \]
\[\delta x = (b-a)/n = (2\pi-\pi)/n = pi/n\]
\[x_i = a + \delta x \cdot i = \pi + \pi/n \cdot i \]
Therefore
\[\int_{\pi}^{2\pi} \cos(x)dx = \lim_{n\to \infty}\sum_{i=1}^{n} \frac{\pi}{n}\cdot \cos(\pi+\frac{\pi i}{n}) \]

Reference:
https://www.khanacademy.org/math/ap-calculus-ab/ab-integration-new/ab-6-3/a/definite-integral-as-the-limit-of-a-riemann-sum


Thursday, April 2, 2020

Math resources

residue theorem
https://math.mit.edu/~jorloff/18.04/notes/topic8.pdf

A table of integrals of exponential integral - NIST Page
https://nvlpubs.nist.gov/nistpubs/jres/73B/jresv73Bn3p191_A1b.pdf

Ten lessons I should have been taught. Lecture delivered by Gian-Carlo Rota at MIT on April 20, 1996, on occasion of the Rotafest.
Gian-Carlo Rota

USEFUL VECTOR AND TENSOR OPERATIONS
https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781118127575.app1

// with very good examples

Riccati equation
\[ dy/dx = a(x) + b(x)y + c(x)y^2 \]

quasi-linear newton Broyden’s Method

Table of Approximations for Derivatives // important for finite difference

SDE 




pde



laptops



HP Laptop - 15t   $579         min 480$
10th Gen Intel® Core™ i7 processor

2019 Dell Inspiron 14" Laptop Computer| 10th Gen Intel Quad-Core i5 1035G4  $398

HP 17.3" Laptop - 10th Gen Intel Core i5-10210U  (1600 x 900) Touchscreen  12G RAM 499


HP 17.3" HD+ Laptop, Intel Core i7-8565U 1600*900 8GB Memory, 256GB SSD  569






AMD 4700, 8G, 256 NvME 15.6'', 1920*1080