Square Root of a Negative Number Squared
Date: 01/23/97 at 12:05:48
From: Cindy Smith
Subject: Re: Exponent Rules
Hi,
I'm reading popular math books in addition to my textbook and am
really trying to understand the material. Here's my question:
I understand that the nth root of x^n = x^(n/n) or x^1. My textbook
gives two problems: Sqrt(-6)^2 and the 4th root of (-3)^4. This
leads to two different solutions in my mind. (-6)^2 = 36 so the
square root of (-6)^2 = 6. Similarly, the 4th root of (-3)^4 leads to
the fourth root of 81, which is 3. However, according to the rules,
the nth root of x^n = x^(n/n). Therefore, the square root of (-6)^2
should equal (-6)^(2/2) or (-6)^1, which equals -6. By a similar
method, the fourth root of (-3)^4 = (-3)^(4/4) or (-3)^1, which
equals -3. The answers in the back of the book says the correct
answers are positive 6 and 3. Where is the error in my logic?