Answers

2016-01-21T21:07:57+05:30
A.T.P,
m{ 2a +(m-1)d}=n{2a+(n-1)d}
m{2a+md-d}=n{2a+(n-1)d}
2am+m2d-md+2an+n2d-nd
2am-2an+m2d-n2d-md+nd=0   [m2 and n2 means "m" square and "n" square]
2a(m-n)+d(m2-n2)-d(m-n)+0
(m-n){2a+(m+n-1)d}=0
2a+(m+n-1)d=0
(m+n)th term=0
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