Question

find the sum of the first 24 terms of AP whose nth term is given by 3+2n
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Answer 1

Answer:

n = 24 a(n)= 3+2n

first term of the AP = a(1)=3 +2×  1

                                        = 5            

                          a(24)= 3 + 2×24

                                   = 51

hence a=5 ; a(l)=51  ; n = 24

s(n) = (n/2)(a+a(l)

         = (24/2)(5+51)

         = 12(56)

         = 672

hence required answer is 672.