If the first,second and last term of an AP are a,b and 2a respectively, then find the sum

Asked by snehamapink | 13th Feb, 2012, 04:18: PM

Expert Answer:

Tn = 2a = a + (n-1)(b-a) , Here Common difference = b-a
So n = b/(b-a)
Sum = n/2{first term + last term}
= b/2(b-a) { 3a } = 3ab/2(b-a)

Answered by  | 14th Feb, 2012, 03:32: PM

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