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The sum of n terms of an AP is 1/2an^(2...

The sum of n terms of an AP is ` 1/2an^(2)` +bn . Find the common difference.

Text Solution

Verified by Experts

The correct Answer is:
a
`T_(n)=(S_(n)-S_(n-1))`
`{1/2an^(2)+bn}-{1/2a(n-1)(2)+b(n-1)}`
`={1/2an^(2)+bn}-{1/2an^(2)-an+1/2a+bn-b}=(an+b-1/2a)`
`T_(n-1)=a(n-1)+b-1/2a=(an+b-1/2a)-a`
`d=(T_(n)-T_(n-1))=a`
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