Question
If in the expansion of $\left(2^{x}+\frac{1}{4^{x}}\right)^{n}, \frac{T_{3}}{T_{2}}=7$ and the sum of the coefficients of 2 nd and 3 rd terms is 36 , then the value of $x$ is(A) $-\frac{1}{3}$(B) $-\frac{1}{2}$(C) $\frac{1}{3}$(D) $\frac{1}{2}$
Step 1
The general term in the binomial expansion is given by $T_{r+1} = ^nC_r (a^{n-r})(b^r)$ where $a=2^x$ and $b=\frac{1}{4^x}$. Therefore, the second term $T_2 = ^nC_1 (2^{x(n-1)})(\frac{1}{4^x})$ and the third term $T_3 = ^nC_2 (2^{x(n-2)})(\frac{1}{4^{2x}})$. Show more…
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