Common Misconception: Square Root and Principal Square Root

I was bemused when our consultant showed me a certain part in our textbook and he looked so disappointed. I asked him "Why? I don't see any errors there. What's wrong, sir?"

"This is a common mistake among students, and teachers as well," he said.

We are all familiar with the radical sign (√). A radical sign with out an index (a number on the upper left part of the symbol), indicates square root.

If we say "Find the square root of 9," in symbol that is . We know that the answer to the square root of 9 is + 3 and –3. But take note that when we deal with symbols, the radical sign pertains to the principal square root of the number. The principal square root of the number is that one square root of the number that is NOT negative. Therefore, there "square root of 9" is different from .

WolframAlpha

First post, dedicated to WolframAlpha. Making the world’s knowledge computable
is WolframAlpha's tagline. And yes! They live to their words. This site is a big help for teachers, students, and even parents. Can you imagine how easy it will be if you just type each of your homework there and they compute it for you? Easy peasy eh? Students nowadays must be very happy. But where is the learning there?
There are always pros and cons. So, to make things clearer and realistic, we're listing the pros and cons for you.

Pro #1: Computation is very easy. As simple as tweeting you question then, a bot auto replies.
Con #1: You won't know how it is solved. What if your teacher calls you in front to explain your answer? How about during exams? You are not allowed to access the internet, right?
Pro #2: For teachers, this may help you save time in preparing answer keys. But we're not sure if the accuracy in the answer it gives is 100% correct.
Pro #3: For Parents,  if your kids run to you for help in their homework and you are very much aware that you, too lacked the skills in math, Wolfram is your knight in shining armor. But then again, come Con #1. You, too, wont be able to explain to your kid how you got the answer.

3 to 1? Quite poor argument. We are not against WolframAlpha because we also use it ourselves. But our point is, PLEASE just use this site as an AID. You may have the correct answer, but at the end of the day, which part did the learning take place?