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the term independent of x in (1+x +2x^2)...

the term independent of x in `(1+x +2x^2)((3x^2)/2-1/(3x))^9` is

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To find the term independent of \( x \) in the expression \( (1 + x + 2x^2) \left( \frac{3x^2}{2} - \frac{1}{3x} \right)^9 \), we will follow these steps: ### Step 1: Identify the components We can denote: - \( A = 1 + x + 2x^2 \) - \( B = \left( \frac{3x^2}{2} - \frac{1}{3x} \right)^9 \) ### Step 2: Expand \( B \) using the Binomial Theorem Using the Binomial Theorem, we can expand \( B \): \[ B = \sum_{k=0}^{9} \binom{9}{k} \left( \frac{3x^2}{2} \right)^{9-k} \left( -\frac{1}{3x} \right)^k \] This simplifies to: \[ B = \sum_{k=0}^{9} \binom{9}{k} \left( \frac{3^{9-k}}{2^{9-k}} \right) x^{2(9-k)} \left( -\frac{1}{3} \right)^k x^{-k} \] \[ = \sum_{k=0}^{9} \binom{9}{k} \frac{3^{9-k}}{2^{9-k} \cdot 3^k} (-1)^k x^{18 - 3k} \] \[ = \sum_{k=0}^{9} \binom{9}{k} \frac{3^{9-k}}{2^{9-k}} (-1)^k x^{18 - 3k} \] ### Step 3: Find the term independent of \( x \) To find the term independent of \( x \) in \( B \), we need \( 18 - 3k = 0 \): \[ 18 = 3k \implies k = 6 \] Now, substitute \( k = 6 \) into the expansion: \[ \text{Term for } k=6 = \binom{9}{6} \frac{3^{3}}{2^{3}} (-1)^6 x^{0} \] Calculating this: \[ \binom{9}{6} = \binom{9}{3} = \frac{9 \times 8 \times 7}{3 \times 2 \times 1} = 84 \] \[ \text{Term} = 84 \cdot \frac{27}{8} = \frac{2268}{8} = 283.5 \] ### Step 4: Combine with \( A \) Now we need to consider the contribution from \( A \): - The term independent of \( x \) in \( A \) is \( 1 \). - The term independent of \( x \) in \( B \) is \( 283.5 \). Thus, the total term independent of \( x \) is: \[ 1 \cdot 283.5 = 283.5 \] ### Step 5: Final Answer Therefore, the term independent of \( x \) in the expression \( (1 + x + 2x^2) \left( \frac{3x^2}{2} - \frac{1}{3x} \right)^9 \) is: \[ \frac{17}{54} \]
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