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Comment on Introduction to Square Roots
So I'm assuming that we don't
That's correct.
That's correct.
https://gre.myprepclub.com/forum
I wanted to confirm that when we see a square root on gre we should only take its positive value and ignore the negative? I recall getting one quantitative comparison question wrong as I didn't consider the negative value of the square root.
Question link: https:/
Question link: https://gre.myprepclub.com/forum/topic11876.html
You are correct. The square root notation (√), tells us to take POSITIVE value only.
For example, √25 = 5, √81 = 9 and √0.25 = 0.5
IMPORTANT: Some people conflate the above notation issue with equations involving powers of 2.
For example, the equation x² = 9 does not have any square root notation.
So, we must recognize that there are TWO possible solutions: x = 3 and x = -3.
Likewise, the equation x² = 100 also has TWO possible solutions: x = 10 and x = -10.
In general, we can write: If x² = k, then there are two solutions: x = √k and x = -√k
Does that help?
Cheers,
Brent
Hi Brent,
In https://gre.myprepclub.com/forum/topic11876.html
why 0.06 is squared instead of it (0.06)^2 =0.036
so squareroot of (0.036) = 0.06
what is wrong in this
Thanks
Question link: https:/
Question link: https://gre.myprepclub.com/forum/topic11876.html
Your calculations are missing a zero.
(0.06)² = 0.0036 (not 0.036)
Cheers,
Brent
https://gre.myprepclub.com/forum
For this question, I just plugged in some of the integers and I got Quantity A is biggerl. Is this a right way to do it or did I just get lucky?
Thanks
Question link: https:/
Question link: https://gre.myprepclub.com/forum/x-is-an-integer-11296.html
The problem is that testing numbers will never yield definitive results UNLESS the correct answer is D.
I cover this at 2:50 in the following video: https://www.greenlighttestprep.com/module/gre-quantitative-comparison/vi...
Having said that, if you keep testing numbers and you get the same result each time (e.g., Quantity A is greater), then that certainly SUGGESTS that the correct answer is A.
Does that help?
For sq rt of (-25) ^ 2. Is
That's a great (clever)
That's a great (clever) question.
Regardless of how the expression is set up, there are still implied some orders of operation.
Here's what I mean:
The answer to that question depends on whether there are any additional brackets. Here are 2 cases:
case i: [sqrt of (-25)]^2
In other words, [√(-25)]²
In this case, we must evaluate √(-25) first
Since there is no (real) square root of -25, we can conclude that [√(-25)]² has no real value.
case ii: sqrt of [(-25)]^2
In other words, √[(-25)²]
In this case, we must evaluate (-25)² first
(-25)² = 625, so √[(-25)²] = √625 = 25
ASIDE: I should also mention that in your solution, you are taking the square root TWICE.
You have: sqrt of (-25)^2 = [(-5)^2]^1/2, when it should be sqrt of (-25)^2 = [(-25)^2]^1/2
Does that help?
Yup for sure. Thanks so much.
Hey Brent
y^2 = 64 then EITHER y=8 OR y=−8
so whenever i sq root a square should i consider two values?
General property #1:
General property #1:
If √(x²) = k, where k > 0, then x = k or x = -k
General property #2:
If (√x)² = k, where k > 0, then x = k
Q: Why does general property #2 yield only one value for x?
A: Because we can't take the square root of a negative value.
I'm confused as to how the
The square root of -5 does
The square root of -5 does not have a real value.
If you're referring to 5:25 in the lesson, keep in mind that we are finding the square root of (-5)² and not the square root of -5.
Since (-5)² = 25, we are really taking the square root of 25.
Does that help?