JEE MainMathematicsSequences and SeriesMCQ+4 / −1
If are in an A.P. and a are also in an A.P, then is equal to
- A
- B
- C
- D
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Correct answer: B
- Since are in A.P., the middle term is the average of the other two:
Using log properties,
- Now consider the second A.P.:
First simplify each term:
Since these are in A.P.,
Combine logs:
Hence,
Cross-multiplying,
So,
- Using , , so
From , let
Then
Thus,
Multiply by :
- Therefore the correct option is:
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