Rallias Ubernerd's Journal: Value of i

Yesterday I took the NWEA tests, and got a score of 276 (many people who have taken school since the advent of the computer probably know that this score corresponds with Calculus, or in that area). That isn't that important. What I'm wondering is, I got a question where the square root ended up negative, and it wanted an "exact" answer. The answer choices included a symbol I have never seen before. It is i, and it showed something like (3 / 4 + sqrt(7) i / 5 , 3 / 4 - sqrt(7) i / 5), and I wonder what it is. Can someone help me?

The Imaginary Number

[damn_registrars]

If I'm reading your question and equation right, the "i" you are looking at corresponds to the imaginary number (or imaginary constant). Essentially, "i" represents the square root of -1 (negative one). You can then use "i" to evaluate the square root of any negative number you want - for example the square root of negative four would be "2i".

Certain branches of math and physics will represent the imaginary number on its own dimension for certain types of work, you'll see an x-y plot where the x-axis is