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CEO
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The expresion SQRT(57-40*SQRT2) - SQRT(57+40*SQRT2) is equal [#permalink]
 06 Dec 2003, 15:59
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6. The expresion SQRT(57-40*SQRT2) - SQRT(57+40*SQRT2) is equal to :
a. 10 b. -10 c. 101/10 d.-101/10 e.-SQRT41
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Director
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Raise the whole expression to power 2 and solve it. Think it should be 10..
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Intern
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squaring the entire expression
if a = 57
and b = 40*2^1/2
a^2 + b^2 -2((a+b)(a-b))^1/2. siplyfiy to get 114-2(49)^1/2 = 100
Ans = 10
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Senior Manager
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is bat_car's work correct?
How would you get a^2 + b^2 -2((a+b)(a-b))^1/2
shouldn't it be 2a -2((a+b)(a-b))^1/2
also the value of the squared expression comes to be 100
so taking its square root how do we get only 10. Shouldn't it be -10 as well??
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SVP
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End result of whole expression squared is 100. SO sqrt of 100 either -10 or +10.
But if you see the orginal expression
SQRT(57-40*SQRT2) < SQRT(57+40*SQRT2)
SO the answer should be -10
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Senior Manager
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I agree with Anand.
The answer should be -10.
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