Question

if the sum of n terms of an ap is 2n^2+5n find its 10th term and nth term don't scam please or i will report​

Answer 1

Answer:

 Given Sn  = 2n²  + 5n

Sn − 1  = 2( n −1)²   + 5( n − 1 )

= 2( n² - 2n + 1 ) + 5n − 5

= 2n²  − 4n + 2 + 5n − 5

= 2n²  + n − 3

Now,  tn = Sn  − Sn − 1

​ = 2n²  + 5n − ( 2n²  + n − 3 )

= 2n²  + 5n − 2n²  − n + 3

= 4n+3

Hope it helps you!!

:)

Answer 2

Step-by-step explanation:

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Given Sn=2n2+5n

Sn−1=2(n−1)2+5(n−1)

           =2(n2−2n+1)+5n−5

           =2n2−4n+2+5n−5

           =2n2+n−3

Now,  tn=Sn−Sn−1

               =2n2+5n−(2n2+n−3)

               =2n2+5n−2n2−n+3

               =4n+3