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If p^(4)+q^(3)=2(p gt 0, q gt 0), then t...

If `p^(4)+q^(3)=2(p gt 0, q gt 0)`, then the maximum value of term independent of `x` in the expansion of `(px^((1)/(12))+qx^(-(1)/(9)))^(14)` is (a) `"^(14)C_(4)` (b) `"^(14)C_(6)` (c) `"^(14)C_(7)` (d) `"^(14)C_(12)`

A

`"^(14)C_(4)`

B

`"^(14)C_(6)`

C

`"^(14)C_(7)`

D

`"^(14)C_(12)`

Text Solution

AI Generated Solution

The correct Answer is:
To find the maximum value of the term independent of \( x \) in the expansion of \( (px^{\frac{1}{12}} + qx^{-\frac{1}{9}})^{14} \), we will follow these steps: ### Step-by-Step Solution: 1. **Identify the General Term**: The general term \( T_r \) in the expansion of \( (a + b)^n \) is given by: \[ T_r = \binom{n}{r} a^{n-r} b^r \] Here, \( a = px^{\frac{1}{12}} \), \( b = qx^{-\frac{1}{9}} \), and \( n = 14 \). Thus, the general term becomes: \[ T_r = \binom{14}{r} (px^{\frac{1}{12}})^{14-r} (qx^{-\frac{1}{9}})^r \] 2. **Simplify the General Term**: \[ T_r = \binom{14}{r} p^{14-r} q^r x^{\frac{14-r}{12} - \frac{r}{9}} \] 3. **Find the Power of \( x \)**: We need the power of \( x \) to be zero for the term to be independent of \( x \): \[ \frac{14 - r}{12} - \frac{r}{9} = 0 \] 4. **Solve for \( r \)**: To solve the equation, find a common denominator (which is 36): \[ \frac{3(14 - r)}{36} - \frac{4r}{36} = 0 \] This simplifies to: \[ 42 - 3r - 4r = 0 \implies 42 - 7r = 0 \implies 7r = 42 \implies r = 6 \] 5. **Substitute \( r \) Back into the General Term**: Substitute \( r = 6 \) into the general term: \[ T_6 = \binom{14}{6} p^{14-6} q^6 = \binom{14}{6} p^8 q^6 \] 6. **Maximize the Value of \( p^8 q^6 \)**: We are given that \( p^4 + q^3 = 2 \). To maximize \( p^8 q^6 \), we can apply the AM-GM inequality: \[ \frac{p^4 + q^3}{2} \geq \sqrt{p^4 q^3} \] From \( p^4 + q^3 = 2 \): \[ 1 \geq \sqrt{p^4 q^3} \implies p^4 q^3 \leq 1 \] Squaring both sides gives: \[ (p^4 q^3)^2 \leq 1 \implies p^8 q^6 \leq 1 \] 7. **Final Result**: Thus, the maximum value of the term independent of \( x \) is: \[ T_6 \leq \binom{14}{6} \cdot 1 = \binom{14}{6} \] ### Conclusion: The maximum value of the term independent of \( x \) in the expansion is \( \binom{14}{6} \).

To find the maximum value of the term independent of \( x \) in the expansion of \( (px^{\frac{1}{12}} + qx^{-\frac{1}{9}})^{14} \), we will follow these steps: ### Step-by-Step Solution: 1. **Identify the General Term**: The general term \( T_r \) in the expansion of \( (a + b)^n \) is given by: \[ T_r = \binom{n}{r} a^{n-r} b^r ...
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