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If Sn=n P+(n(n-1))/2Q ,w h e r eSn denot...

If `S_n=n P+(n(n-1))/2Q ,w h e r eS_n` denotes the sum of the first `n` terms of an A.P., then find the common difference.

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Given,
`S_n=nP+[n(n-1)Q]/2`
Let the first term of the A.P be a and the common difference be d,
the sum of n terms is `S_n=n/2[2a+(n-1)d]`
...
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RD SHARMA-ARITHMETIC PROGRESSIONS-Solved Examples And Exercises
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  19. Find the A.M. between: (x-y)a n d\ (x+y)

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  20. Insert 4 A.M.s between 4 and 19.

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