Fourier Series
 Infinite series of sin and cos, that is used to solve differential
equations
 The Fourier series are made by combining an infinite amount of
waves, to make them represent a function(for example a
square wave). The more waves there are added to the
functions, the more they start to look like the wanted function
 It is also used to present square functions with cos and sinwave functions
 To form a Fourier series, we need to use a function and
multiply it by cos and sin
 The function is easy to build, because most of the function will
be =0.
 To make a square wave, we can start with sin and sin(3x)/3,
and combine them together. After, we can start adding infinite
amounts of waves that increase their t and a, by following the
equation below.
 𝑓(𝑡) = 𝑎0 + 𝑎1 sin(𝑡) + 𝑎2 sin(2𝑡) + 𝑎3 sin⁡(3𝑡)…