A logic gate is an idealized model of computation or physical electronic device implementing a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device (see Ideal and real op-amps for comparison).

# Microservices 🔗

Microservice architecture – a variant of the service-oriented architecture (SOA) structural style – arranges an application as a collection of loosely coupled services. In a microservices architecture, services are fine-grained and the protocols are lightweight.

# CPU 💻

A central processing unit (CPU), also called a central processor,main processor or just processor, is the electronic circuitry within a computer that executes instructions that make up a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs).

# Gas Station ⛽

A gas station, also known as a filling station, fueling station, service station or petrol station is a facility which sells fuel and lubricants for motor vehicles. The most common fuels sold are gasoline (petrol) or diesel fuel. Many gas stations have a convenience store close to the pumps, to make extra earnings. Some have tunnel car washs.

# Formulas (1948-1994) 🧮

1948$$H(S) \leqslant m(S) \leqslant H(S) + 1$$
The mathematician Claude Shannon introduced the entropy in information theory in 1948. Entropy in information theory can be defined as the expected number of bits of information contained in an event. For instance, tossing a fair coin has the entropy of 1. It is because of the probability of having a head or tail is 0.5. The amount of information required to identify it’s head or tail is one by asking one, yes or no question — “is it head ? or is it tail?”. If the entropy is higher, that means we need more information to represent an event. Now, we can say that entropy increases with increases in uncertainty. Another example is that crossing the street has less number of information required to represent / store / communicate than playing a poker game.

# Formulas (1901-1927) 🧮

1901$$\begin{array}{c}P\left(\frac{X_{1}+X_{2}+\cdots+X_{n}-n_{\mu}}{\sigma \sqrt{n}} \leq x\right) \\rightarrow \\frac{1}{\sqrt{2 \pi}} \int_{-\infty}^{x} e^{-t^{2} / 2} d t\end{array}$$
Lyapunov’s theorem in probability theory is a theorem that establishes very general sufficient conditions for the convergence of the distributions of sums of independent random variables to the normal distribution.
Lyapunov functions (also called the Lyapunov’s second method for stability) are important to stability theory of dynamical systems and control theory. A similar concept appears in the theory of general state space Markov chains, usually under the name Foster–Lyapunov functions.

# Formulas (1825-1896) 🧮

1825$$\oint_{\gamma} f(z) d z=0$$
Cauchy’s integral formula, named after Augustin-Louis Cauchy, is a central statement in complex analysis. It expresses the fact that a holomorphic function defined on a disk is completely determined by its values on the boundary of the disk, and it provides integral formulas for all derivatives of a holomorphic function. Cauchy’s formula shows that, in complex analysis, “differentiation is equivalent to integration”: complex differentiation, like integration, behaves well under uniform limits – a result that does not hold in real analysis.

# Formulas (1500-1799) 🧮

1500$$\begin{aligned}&x^{3} + mx = n\&\Rightarrow\&x=\sqrt[3]{\sqrt{\frac{n^{2}}{4}+\frac{m^{3}}{27}}+\frac{n}{2}}-\sqrt[3]{\sqrt{\frac{n^{2}}{4}+\frac{m^{3}}{27}}-\frac{n}{2}}\end{aligned}$$
At some point in the early 1500’s, an Italian mathematician named Scipione del Ferro determined a general solution for what is known as the depressed cubic equation. This is cubic equation without any $x^{2}$ terms. The general form is : $x^{3} + mx = n$ . As it turns out, any cubic equation of the form $x^{3} + bx^{2} + cx + d = 0$ can be written as a depressed cubic, but that came later.

# Frozen ☃️

Born with the power of ice and snow, Elsa is the firstborn daughter of King Agnarr and Queen Iduna, the older sister of Queen Anna, and the former queen of Arendelle. Throughout most of her young life, Elsa feared that her powers were monstrous. Therefore, she isolated herself from the world as a means of protecting her family and kingdom. Elsa’s anxieties would eventually trigger a curse that plunged Arendelle into an eternal winter. Through Anna’s love, however, Elsa was able to control her powers and live peacefully amongst her people with a newfound self-confidence.

# IELTS 📚

The International English Language Testing System, or IELTS, is an international standardized test of English language proficiency for non-native English language speakers. It is jointly managed by the British Council, IDP: IELTS Australia and Cambridge Assessment English, and was established in 1989. IELTS is one of the major English-language tests in the world.
Year started: 1980, 40 years ago
Purpose: To assess the English language proficiency of non-native English speakers.
Fee: Around 250 USD
Knowledge / skills tested: Listening, reading, writing and speaking of the English language.
Score / grade validity: 24 Months