if s>0 and root r/s = s, what is r in terms of s?
a. 1/s
b. root s
c. s root s
d. s^3
e. s^2-s
I tried picking numbers but I could figure out what to put in for the values!
qa is d
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gmatguy16
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please include brackets in questions as much as possible root r/s could be interpreted as root(r)/s or root(r/s).of course in this case it was simple to figure out but other complex questions it does help.
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sfiqal
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For this question, initially I got a C. I did it this way:
squareroot (r/s) = s
squareroot both side and get
r/s = squareroot s
and finally
r= s squareroot (s)
Okay, I now know that this is wrong but why is this way wrong? Why can't we squareroot both sides (instead of squaring both sides which is the the right way)?
squareroot (r/s) = s
squareroot both side and get
r/s = squareroot s
and finally
r= s squareroot (s)
Okay, I now know that this is wrong but why is this way wrong? Why can't we squareroot both sides (instead of squaring both sides which is the the right way)?
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Hi sfiqal,
From a 'math' standpoint, you can do whatever you like to both sides of an equation. However, when you square-root a calculation that has already been square-rooted, that 'act' does NOT cancel out the square-root... it turns the result into a quad-root.
For example, if you have the square-root of 16, then take the square-root of THAT number, you have...
Square-root of 16 = 4.... square-root of 4 = 2.....
Thus, the quad-root of 16 = 2
To "undo" a square-root, you have to SQUARE both sides of the equation, just as the correct answer does in this question.
GMAT assassins aren't born, they're made,
Rich
From a 'math' standpoint, you can do whatever you like to both sides of an equation. However, when you square-root a calculation that has already been square-rooted, that 'act' does NOT cancel out the square-root... it turns the result into a quad-root.
For example, if you have the square-root of 16, then take the square-root of THAT number, you have...
Square-root of 16 = 4.... square-root of 4 = 2.....
Thus, the quad-root of 16 = 2
To "undo" a square-root, you have to SQUARE both sides of the equation, just as the correct answer does in this question.
GMAT assassins aren't born, they're made,
Rich
