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The-first-second-and-middle-terms-of-an-AP-are-a-b-c-respectively-Their-sum-is-




Question Number 32745 by vakil vishaWakrma last updated on 01/Apr/18
The first, second and middle terms of an  AP are a, b, c respectively. Their sum is
Thefirst,secondandmiddletermsofanAParea,b,crespectively.Theirsumis
Answered by Rasheed.Sindhi last updated on 01/Apr/18
Let the AP has n (odd) terms and common  difference d.  d=b−a  The middle term=(((n+1)/2))th term=c            c=a+(((n+1)/2)−1)(b−a)              ((n−1)/2)=((c−a)/(b−a))              n=((2(c−a))/(b−a))+1                 =((2c−2a+b−a)/(b−a))                 =((−3a+b+2c)/(b−a))  Sum=(middle-term)×(number of terms)             =c×n=c(((−3a+b+2c)/(b−a)))                      =(c/(b−a))(−3a+b+2c)
LettheAPhasn(odd)termsandcommondifferenced.d=baThemiddleterm=(n+12)thterm=cc=a+(n+121)(ba)n12=caban=2(ca)ba+1=2c2a+baba=3a+b+2cbaSum=(middleterm)×(numberofterms)=c×n=c(3a+b+2cba)=cba(3a+b+2c)

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