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If a1,a,a3...an are in A.P then prove th...

If `a_1,a_,a_3...a_n` are in A.P then prove that `a_1^2-a_2^2+a_3^2-a_4^2+....a_(2k-1)^2-a_(2k)^2= (k/(2k-1))(a_1^2-a_(2k)^2)`

A

`(k -1)/(k + 1)`

B

`(k)/(2k - 1)`

C

`(k+ 1)/(2k + 1)`

D

None of these

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The correct Answer is:
B
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