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[ (√5 +√√5) - (√5 -√√5)]^2 =
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Updated on: 22 Oct 2020, 15:55
Updated on: 22 Oct 2020, 15:55
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Question Stats:
60% (07:09) correct
39% (02:33) wrong based on 69 sessions
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\(( \sqrt{5+\sqrt{5}} - \sqrt{5-\sqrt{5}} )^2\)
A. \(10-4 \sqrt{5}\)
B. \(10-2 \sqrt{5}\)
C. \(20-8 \sqrt{5}\)
D. \(20-4 \sqrt{5}\)
E. \(20 - 2 \sqrt{5}\)
Kudos to right answer !!
A. \(10-4 \sqrt{5}\)
B. \(10-2 \sqrt{5}\)
C. \(20-8 \sqrt{5}\)
D. \(20-4 \sqrt{5}\)
E. \(20 - 2 \sqrt{5}\)
Kudos to right answer !!
Re: [ (√5 +√√5) - (√5 -√√5)]^2 =
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22 Oct 2020, 15:00
22 Oct 2020, 15:00
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Sunsha wrote:
Kudos to right answer !!
Let
\(A=\sqrt{5+sqrt(5)}\) and
\(B = \sqrt{5-sqrt(5)}\)
\((A-B)^2 = A^2-2AB+B^2\)
\(A^2+B^2\)=\(5+\sqrt{5}+5-\sqrt{5}=10\)
\(-2AB=-2\sqrt{5^2-5}=-4\sqrt{5}\)
Therefore, \((A-B)^2\) = \(10-4\sqrt{5}\)
Answer is A
Re: [ (√5 +√√5) - (√5 -√√5)]^2 =
[#permalink]
22 Oct 2020, 15:51
22 Oct 2020, 15:51
Expert Reply
The question must be formatted Sir as I edited above.
The images are not allowed on the board but for geometry or DI questions to show the figures
Regards
The images are not allowed on the board but for geometry or DI questions to show the figures
Regards
