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If the middle term in the expansion of `((1)/(x)+x sinx)^(10)` is equal to `7(7)/(8)`, then the number of values of x in `[0, 2pi]` is equal to

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To solve the problem, we need to find the middle term in the expansion of \(\left(\frac{1}{x} + x \sin x\right)^{10}\) and set it equal to \(\frac{7}{8}\). We will then determine the values of \(x\) in the interval \([0, 2\pi]\). ### Step 1: Identify the middle term in the expansion For the expansion of \((a + b)^n\), the middle term when \(n\) is even is given by: \[ T_{r+1} = \binom{n}{r} a^{n-r} b^r \] where \(r = \frac{n}{2}\). Here, \(n = 10\), so \(r = \frac{10}{2} = 5\). The middle term \(T_6\) is: \[ T_6 = \binom{10}{5} \left(\frac{1}{x}\right)^{10-5} \left(x \sin x\right)^5 \] ### Step 2: Calculate the middle term Substituting the values into the formula: \[ T_6 = \binom{10}{5} \left(\frac{1}{x}\right)^{5} \left(x \sin x\right)^{5} \] \[ = \binom{10}{5} \cdot \frac{(x \sin x)^5}{x^5} \] \[ = \binom{10}{5} \cdot \sin^5 x \] ### Step 3: Calculate \(\binom{10}{5}\) \[ \binom{10}{5} = \frac{10!}{5!5!} = \frac{10 \times 9 \times 8 \times 7 \times 6}{5 \times 4 \times 3 \times 2 \times 1} = 252 \] ### Step 4: Set the middle term equal to \(\frac{7}{8}\) Now we set the middle term equal to \(\frac{7}{8}\): \[ 252 \sin^5 x = \frac{7}{8} \] ### Step 5: Solve for \(\sin^5 x\) Rearranging gives: \[ \sin^5 x = \frac{7}{8 \times 252} = \frac{7}{2016} \] ### Step 6: Solve for \(\sin x\) Taking the fifth root: \[ \sin x = \left(\frac{7}{2016}\right)^{\frac{1}{5}} \] ### Step 7: Finding the values of \(x\) The sine function is positive in the first and second quadrants. Therefore, we have: 1. \(x = \arcsin\left(\left(\frac{7}{2016}\right)^{\frac{1}{5}}\right)\) 2. \(x = \pi - \arcsin\left(\left(\frac{7}{2016}\right)^{\frac{1}{5}}\right)\) ### Step 8: Count the values in \([0, 2\pi]\) In the interval \([0, 2\pi]\), the sine function will yield two solutions: 1. One in the first quadrant 2. One in the second quadrant Thus, the total number of values of \(x\) in the interval \([0, 2\pi]\) is **2**. ### Final Answer The number of values of \(x\) in \([0, 2\pi]\) is **2**.
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