Let a1 be the first term and d be the common difference of A.P.
∴S11=0⇒211(2a1+10d)=0
⇒a1+5d=0
Now a1+a3+a5+….+a23=212(2a1+(12−1)2d) =12(a1+11d)
=12(a1−511a1)
=−572a1
If the sum of first 11 terms of an A.P. ,a1,a2,a3…… is 0(a1=0) then the sum of the A.P a1,a3,a5,…..a23 is ka1 where k is equal to
Held on 2 Sept 2020 · Verified 6 Jul 2026.
−10121
10121
572
−572
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