In math, you were always told, "well, you were told you cannot ____, but really you can."
Lies, all lies!
Recall that in 1st or 2nd grade you were told you cannot subtract a larger number from a smaller number (for example 3 - 5 = doesn't exist).
Well, then you enter 5th or 6th grade and learn that you can. The number is called negative. But never take the square root of a negative number (for example sqrt(9) = + or - 3 but sqrt(-9) = doesn't exist).
However, you then enter 9th or 10th grade, and guess what? You really can take the square root of a negative number. You call this number imaginary, and give it the letter i. For example sqrt(-9) = + or - 3i. However, the square root function is okay. BUT never, ever, ever take the logarithm of a negative number (for example log(100) = 2 but log(-1) = doesn't exist).
Or does the log(-1) exist? Hmmm?! Might need to go ask Mr. Owl.