Question

The sum of the first n terms of an AP is [5n²/2 + 3n/2] . find the N the term and the 20th term of this AP

Answer 1

Hey there !!


➡ Given :-

→ S$\tiny n$ = $( \frac{5 {n}^{2} }{2} + \frac{3n}{2} ).$


➡ To find :-

→ nth term.

→ 20th term [ a$\tiny n$ ] .


➡ Solution :-

▶ See the attachment.


✔✔ Hence, nth term = ( 5n - 1 ) . ✅✅

And,

→ 20th term = 5(20) - 1.

=> a$\tiny 20$ = 100 - 1 .

•°• a$\tiny 20$ = 99.


✔✔ Hence, it is solved ✅✅.

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THANKS


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