Square roots-Maths
This topic has expert replies
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi acegmat29,
The GMAT limits square roots to the POSITIVE root only. You still have to pay careful attention to what the prompt presents though.
For example:
While (Root9) = +3
(RootX^2) = 4 means that X could be 4 or -4
GMAT assassins aren't born, they're made,
Rich
The GMAT limits square roots to the POSITIVE root only. You still have to pay careful attention to what the prompt presents though.
For example:
While (Root9) = +3
(RootX^2) = 4 means that X could be 4 or -4
GMAT assassins aren't born, they're made,
Rich
-
- GMAT Instructor
- Posts: 2630
- Joined: Wed Sep 12, 2012 3:32 pm
- Location: East Bay all the way
- Thanked: 625 times
- Followed by:119 members
- GMAT Score:780
It isn't just the GMAT, math in general limits square roots to nonnegative solutions.
This is a tradition that stems back to the Greeks, who didn't recognize the existence of negative numbers. Since they inaugurated (or at least popularized) the notion of square roots, we go with that.
In practical terms, this means that, as you say, x² = 1 has two solutions, but √1 only has one.
This is a tradition that stems back to the Greeks, who didn't recognize the existence of negative numbers. Since they inaugurated (or at least popularized) the notion of square roots, we go with that.
In practical terms, this means that, as you say, x² = 1 has two solutions, but √1 only has one.
-
- GMAT Instructor
- Posts: 2630
- Joined: Wed Sep 12, 2012 3:32 pm
- Location: East Bay all the way
- Thanked: 625 times
- Followed by:119 members
- GMAT Score:780
While (Root9) = +3
(RootX^2) = 4 means that X could be 4 or -4[/quote]
This is hard to follow without notation, so if anyone is confused, what Rich is saying here is
√9 = 3
√x² = 4 means x² = 16 means x = ±4.
(RootX^2) = 4 means that X could be 4 or -4[/quote]
This is hard to follow without notation, so if anyone is confused, what Rich is saying here is
√9 = 3
√x² = 4 means x² = 16 means x = ±4.