Question

A sequence consists of the positive odd integers 1, 3, 5,. What's the sum of the first 12 terms of the

sequence?

Answer 1

hi

we have an aroithmetic serie of first term 1 and pace 2

so sum of 12 first terms, namming 1 as S1 and 12th term as S12

S12 = 1 + 2*11 = 23

formula of summ : number of term * ( final term + first term) / 2

So sum of terms from S1 +S12 = 12 ( S12 +S1 ) / 2 = 12 * ( 23+1) /2

12* 12= 144

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