The harmonic series,

$$

1+\frac1{2}+\frac1{3}+\frac1{4}+\frac1{5}+\dots =\sum_{n=1}^\infty\frac1{n}=?

$$

## One Solution to Git Push Timeout Error - Failed to Connect to 443 Port

When I tried to push a new post to the Github, I received below error message.`Failed to connect to github.com port 443: Timed out`

## Euler's Formula Quiz

The goal is to prove that

$\exp(x+y)\exp(x)\exp(y)$,

or in another form

$e^{(x+y)}=e^x+e^y$.

## Geometry Complex Numbers and Trigonometry

Being tired of memorizing these formulas? See how a unit circle and the complex numbers can help.

$\begin{array}{1}\sin(\alpha+\beta)=\sin\alpha\cos\beta+\cos\alpha\sin\beta\\cos(\alpha+\beta)=\cos\alpha\cos\beta-\sin\alpha\sin\beta\end{array}$

## Another View on the Quadratic Formula

Being tired of memorizing this fomula? Let’s take a look at it from a different perspective.

${\displaystyle x={\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}\ \ }$?

## NPM, Node.js and JavaScript

JavaScript, often abbreviated as JS, is a programming language that conforms to the ECMAScript specification. Alongside HTML and CSS, JavaScript is one of the core technologies of the World Wide Web. HTML is responsible for the structures, CSS is responsible for the decorations, and JavaScript is responsible for the interactions.

## What's the Commonality Between Java and Javascript?

Lots of new programmers and non-tech people have long confused Java and JavaScript, so what’s the commonality? 😏

## Java Comparable Interface

Java Comparable interface is used to order the objects of the user-defined class. This interface is found in java. lang package and contains only one method named compareTo(Object). It provides a single sorting sequence only, i.e., you can sort the elements on the basis of single data member only. This post show an example of sorting apples by their types (string), colors (enum) and weights (int).