In the expansion of `(1 + x)^43` ,the co-efficients of `(2r + 1)th and (r + 2)th` terms are equal. Find `r`.A. 5B. 14C. 21D. 22

In the expansion of `(1 + x)^43` ,the co-efficients of `(2r + 1)th and

1.	In the expansion of `(1 + x)^43` ,the co-efficients of `(2r + 1)th and (r + 2)th` terms are equal. Find `r`.A. 5B. 14C. 21D. 22
Answer» Correct Answer - B Given, in the expression `g(1+x)^(43)`, coefficients of `(2r + 1)^(th)` term and `(r + 2)^(th)` term are equal. Coefficient of `(2r+1)^(th)` term = `n_(C_(2r))` Coefficient of `(r + 2)^(th)` term = `n_(C_(r+1))` `n_(C_(2r))=n_(C_r+1)` `rArr 43_(C_(2r))=43_(C_(r+1))" "(because n = 43)` `rArr 2r + r + 1 = 43` `rArr 3r + 1 = 43` `rArr 3r + 42 rArr r = 14`

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