Question
Mon November 14, 2011 By:
 

if the common difference of an a.p equal the fist term,then prove that ratio of its mth and the Lth terms is m:n.

Expert Reply
Mon November 14, 2011
Let the first term of an AP is a.
 
And as the question says, let us its common differnce is also the a, the first term.
 
Hence mth term = Tm= a+(m-1)d = a+(m-1)a = am
 
Similarly
 
nth term = Tn= a+(n-1)d = a+(n-1)a = an
 
So taking ratios we get 
 
Tm/Tn= am/an = m/n
 
Hence proved
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