Arithmathic Progression

Asked by toppin | 5th Feb, 2010, 02:37: PM

Expert Answer:

am = a0 +(m-1)d = n

an = a0 +(n-1)d = m

Solve these to find a0 and d,

d =(n-m)/(m-n) = -1

a0 = m+n-1

Sm+n = (m+n)(2a0 +(m+n-1)d)/2

= (m+n)(2m+2n-2 - m - n +1)/2

= (m+n)(m+n-1)/2

Regards,

Team,

TopperLearning.

Answered by  | 5th Feb, 2010, 02:50: PM

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