A) 14
B) 15
C) 13
D) 16
Correct Answer: A
Solution :
Coefficient of \[{{(2r+1)}^{th}}\] term in expansion of\[{{(1+x)}^{43}}{{=}^{43}}{{C}_{2r}}\]and coefficient of \[{{(r+2)}^{th}}\] term = coefficient of \[{{\{(r+1)+1\}}^{th}}\] term = \[{}^{43}{{C}_{r+1}}\] According to question \[{}^{43}{{C}_{2r}}={}^{43}{{C}_{r+1}}\] \[={}^{43}{{C}_{43-(r+1)}}\] then \[2r=43-(r+1)\]or \[3r=42\] or \[r=14\].You need to login to perform this action.
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