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Is 7th time the 7th term of an A. P is equal to 11 times the 11term show that the 18th term of an A. P is zero |
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Answer» Answer: GENERAL term of A.P ⇒a n
=a+(n−1)d ⇒ 7 TIMES 7 term = 11 times 11 th term ⇒7(a+6d)=11(a+10d) ⇒7a+42d=11a+110d ⇒42−110d=11a−7a ⇒−68d=4a ⇒−17d=a ___ (1) ∴18 th term = a+17d =−17d+17d (from (1)) =0 ∴18 th term is 0 |
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