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Mathematics Q & A
What is the square route of 99???
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saurabh
September 2008
Its a method to find root Algebraically
SQRT(99) is an irrational, approximately equal to 9.95.
[I bet you already knew that it was just a little less than 10]
Here's how I came up with 9.95 without using a calculator:
Since 10^2 = 100,
Therefore,SQRT(99) must be 10-d where d is much smaller than 1.
A little algebra:
(10-d)*(10-d)=99
100-20*d+d*d =99
1-20*d+d*d = 0
1-20*d = -d*d,
but d << 1 (much smaller than),so d*d is even less
and for a good approximation, we can assume it's 0:
1-20*d ~= 0
d = 1/20 = 0.05
The actual value of SQRT(99) is 9.94987, so our approximation is pretty good.
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amit
September 2008
hey its great!!! ur absolutely correct!!!
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saurabh
September 2008
thanks amit!
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amit
September 2008
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September 2008
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