If `(m+1)^(t h)` term of an A.P. is twice the `(n+1)^(t h)` term, prove that `(3m+1)^(t h)` term is twice the `(m+n+1)^(t h)` term.

Explanation

let `a` is the first term of AP and `d` is the common difference of `A.P`


now ,
according to question ,


`(m+1) th term =2 (n+1) th term`



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