Why are they called "imaginary numbers?"
Despite the fact that they do indeed exist, we call these numbers "imaginary." Why is that? Here are a few reasons why...:
-These numbers used to be thought of as non-existant, hence the word "imaginary." Although now we have concluded that these numbers do exist, we still call them imaginary.
-The word "imaginary" was meant to be downgrading for these numbers, because at a certain point in time they were deemed useless.
-Even after imaginary numbers were concluded as important and useful, mathematicians decided that it would be best to keep that name.
Who first discovered imaginary numbers?
Imaginary numbers are said to be first discovered by Heron of Alexandria who was a Greek mathematician. Although later, the laws of imaginary numbers were first written out by Rafael Bombelli in 1572. [source]
About Heron of Alexandria:
-He is most well known for finding a formula in which you can find the area of a triangle while only knowing its side lengths.
-He has also been known for figuring out a method for computing square roots in a repetitive sort of process.
-Heron was also an engineer and an inventor (an example of an invention by him is a vending machine).
About Rafael Bombelli:
-Bombelli was an italian mathematician most well known for his work with algebra and complex/imaginary numbers.
-In 1572 he wrote a book on algebra (which was called: "Algebra"), where he explained the rules for multiplying positive and negative numbers together.
-He also explained the laws of complex arithmetic in his book.
Heron of Alexandria. [source]
Rafael Bombelli. [source]
The first person to actually call these numbers "imaginary" was Rene Descartes. He used this term in his book entitled "La Geometrie." The word "imaginary" was intended to define these numbers as demeaning. This was because imaginary numbers were seemingly unimportant, just like other numbers were such as zero, negative integers, and decimals. We added these things to the Real Number System, and now we have another number system which uses imaginary numbers. [source]