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The absolute difference of the coefficients of $$x^{10}$$ and $$x^7$$ in the expansion of $$\left(2x^2 + \frac{1}{2x}\right)^{11}$$ is equal to
Given: Find the absolute difference of the coefficients of $$x^{10}$$ and $$x^7$$ in the expansion of $$\left(2x^2 + \frac{1}{2x}\right)^{11}$$.
General term of the expansion:
$$T_{r+1} = \binom{11}{r}(2x^2)^{11-r}\left(\frac{1}{2x}\right)^r = \binom{11}{r} \cdot 2^{11-r} \cdot x^{2(11-r)} \cdot 2^{-r} \cdot x^{-r}$$
$$= \binom{11}{r} \cdot 2^{11-2r} \cdot x^{22-3r}$$
Coefficient of $$x^{10}$$:
Set $$22 - 3r = 10$$, which gives $$r = 4$$.
$$\text{Coefficient} = \binom{11}{4} \cdot 2^{11-8} = 330 \times 2^3 = 330 \times 8 = 2640$$
Coefficient of $$x^7$$:
Set $$22 - 3r = 7$$, which gives $$r = 5$$.
$$\text{Coefficient} = \binom{11}{5} \cdot 2^{11-10} = 462 \times 2^1 = 462 \times 2 = 924$$
Absolute difference:
$$|2640 - 924| = 1716$$
Now, $$12^3 - 12 = 1728 - 12 = 1716$$ ✓
The correct answer is Option D: $$12^3 - 12$$.
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