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If the 6th term in the expansion of ((1)...

If the 6th term in the expansion of `((1)/(x^(8//3))+x^(2)log_(10)x)^(8)` is 5600, then x equals:

A

2

B

`sqrt(5)`

C

`sqrt(10)`

D

10

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To solve the problem, we need to find the value of \( x \) given that the 6th term in the expansion of \( \left( \frac{1}{x^{8/3}} + x^2 \log_{10} x \right)^8 \) is equal to 5600. ### Step-by-Step Solution: 1. **Identify the General Term**: The general term \( T_{r+1} \) in the binomial expansion of \( (a + b)^n \) is given by: \[ T_{r+1} = \binom{n}{r} a^{n-r} b^r \] Here, \( n = 8 \), \( a = \frac{1}{x^{8/3}} \), and \( b = x^2 \log_{10} x \). 2. **Find the 6th Term**: The 6th term corresponds to \( r = 5 \) (since \( T_{r+1} \) corresponds to \( r \)): \[ T_6 = \binom{8}{5} \left( \frac{1}{x^{8/3}} \right)^{8-5} \left( x^2 \log_{10} x \right)^5 \] 3. **Calculate the Binomial Coefficient**: \[ \binom{8}{5} = \binom{8}{3} = \frac{8 \times 7 \times 6}{3 \times 2 \times 1} = 56 \] 4. **Substitute into the Term**: Substitute the values into the expression for \( T_6 \): \[ T_6 = 56 \left( \frac{1}{x^{8/3}} \right)^{3} \left( x^2 \log_{10} x \right)^5 \] \[ = 56 \cdot \frac{1}{x^{8}} \cdot (x^2)^5 \cdot (\log_{10} x)^5 \] \[ = 56 \cdot \frac{x^{10}}{x^{8}} \cdot (\log_{10} x)^5 = 56 \cdot x^{2} \cdot (\log_{10} x)^5 \] 5. **Set the Equation Equal to 5600**: We know that this term equals 5600: \[ 56 \cdot x^{2} \cdot (\log_{10} x)^5 = 5600 \] 6. **Simplify the Equation**: Divide both sides by 56: \[ x^{2} \cdot (\log_{10} x)^5 = \frac{5600}{56} = 100 \] 7. **Rearranging the Equation**: We can express this as: \[ x^{2} = \frac{100}{(\log_{10} x)^5} \] 8. **Assume \( \log_{10} x = y \)**: Then \( x = 10^y \) and substituting gives: \[ (10^y)^{2} = \frac{100}{y^5} \] \[ 10^{2y} = \frac{100}{y^5} \] \[ 10^{2y} = 10^2 \cdot y^{-5} \] 9. **Equate the Exponents**: Since the bases are the same, we can equate the exponents: \[ 2y = 2 - 5 \log_{10} y \] 10. **Solve for \( y \)**: Rearranging gives: \[ 5 \log_{10} y + 2y - 2 = 0 \] This is a transcendental equation and may require numerical methods or graphing to solve. 11. **Final Calculation**: By testing values, we find that \( y = 1 \) (i.e., \( \log_{10} x = 1 \)) gives: \[ x = 10 \] ### Conclusion: Thus, the value of \( x \) is: \[ \boxed{10} \]

To solve the problem, we need to find the value of \( x \) given that the 6th term in the expansion of \( \left( \frac{1}{x^{8/3}} + x^2 \log_{10} x \right)^8 \) is equal to 5600. ### Step-by-Step Solution: 1. **Identify the General Term**: The general term \( T_{r+1} \) in the binomial expansion of \( (a + b)^n \) is given by: \[ T_{r+1} = \binom{n}{r} a^{n-r} b^r ...
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Knowledge Check

  • The third term in the expansion of ((1)/(x)+x^(log_(10)x))^(5), x gt 1 is 1000, then x equals

    A
    100
    B
    10
    C
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    D
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    B
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    C
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    D
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    A
    1
    B
    10
    C
    `10^(-5//2)`
    D
    `10^(2)`
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