1.

The sum of first n terms of an AP is given by `S_n=2n^2 + 3n`. Find the comman difference of the AP.A. 3B. 2C. 6D. 4

Answer» Correct Answer - D
Given ` 1S_(n) = 3n+2n^(2)`
first term of the AP .
`T_(1) =3xx1+2(1)^(2)=3+2=5`
and `T_(1) ==s_(2)-S_(1)`
`=[3xx2+2xx(2)^(2)]-[3xx1+2xx(1)^(2) ]`
` =14-5=9`
`therefore ` Common difference `(d)=T_(2)-t_(1)=9-5=4`


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