Algebra

Complex numbers

Imaginary number

# Assume that
i² = −1
# therefore the imaginary unit is
i = √(-1)

Powers of Imaginary Unit:

The pattern is from i to i⁴, then it repeats.
To evaluate iⁿ, just to get the remainder n % 4 and see…

Equivalent systems of equations

The word equivalent here for system of equation, means both systems have the same solution.
Equations in two systems, don't have to be the same thing at all. If you draw a line for each equation, there could be very different lines for each one.

Radical Equation

Means an equation or an expression that has a square root, cube root, etc.
The symbol is √.

Extraneous solutions of radical equations

𝑒 as a limit

When you do this formula:

Whatever the n is, no matter how large n goes, 
the value of the formula will NOT go insanely big, it will only get closer and closer to the number 2.7....

So we call the number it is approaching as 𝑒. And express the idea as below:

Logarithm

Euler's number ｅ

The Euler's number ｅ actually came from the Compound Interest, for calculating the…