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The number of values of x for which sin^...

The number of values of `x` for which `sin^(-1)(x^2-(x^4)/3+(x^6)/9)+cos^(-1)(x^4-(x^8)/3+(x^(12))/9ddot)=pi/2,` where 0<|x|

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To solve the equation \[ \sin^{-1}\left(x^2 - \frac{x^4}{3} + \frac{x^6}{9} + \ldots\right) + \cos^{-1}\left(x^4 - \frac{x^8}{3} + \frac{x^{12}}{9} + \ldots\right) = \frac{\pi}{2} \] where \(0 < |x| < \sqrt{3}\), we can follow these steps: ### Step 1: Recognize the Identity We know that \[ \sin^{-1}(a) + \cos^{-1}(a) = \frac{\pi}{2} \] for any \(a\) in the range \([-1, 1]\). Therefore, we can set: \[ a = x^2 - \frac{x^4}{3} + \frac{x^6}{9} + \ldots \] and \[ b = x^4 - \frac{x^8}{3} + \frac{x^{12}}{9} + \ldots \] ### Step 2: Find the Infinite Series Sums Both \(a\) and \(b\) are geometric series. For \(a\): \[ a = x^2 \left(1 - \frac{x^2}{3} + \frac{x^4}{9} + \ldots\right) \] This is a geometric series with first term \(x^2\) and common ratio \(-\frac{x^2}{3}\). The sum of an infinite geometric series is given by: \[ S = \frac{a_1}{1 - r} \] Thus, \[ a = \frac{x^2}{1 + \frac{x^2}{3}} = \frac{3x^2}{3 + x^2} \] For \(b\): \[ b = x^4 \left(1 - \frac{x^4}{3} + \frac{x^8}{9} + \ldots\right) \] This is also a geometric series with first term \(x^4\) and common ratio \(-\frac{x^4}{3}\): \[ b = \frac{x^4}{1 + \frac{x^4}{3}} = \frac{3x^4}{3 + x^4} \] ### Step 3: Set Up the Equation Now we have: \[ \frac{3x^2}{3 + x^2} = \frac{3x^4}{3 + x^4} \] ### Step 4: Cross Multiply Cross-multiplying gives: \[ 3x^2(3 + x^4) = 3x^4(3 + x^2) \] Expanding both sides: \[ 9x^2 + 3x^6 = 9x^4 + 3x^6 \] ### Step 5: Simplify the Equation Subtract \(3x^6\) from both sides: \[ 9x^2 = 9x^4 \] Dividing both sides by 9 (assuming \(x \neq 0\)): \[ x^2 = x^4 \] ### Step 6: Rearranging the Equation Rearranging gives: \[ x^4 - x^2 = 0 \] Factoring out \(x^2\): \[ x^2(x^2 - 1) = 0 \] ### Step 7: Solve for \(x\) This gives us: \[ x^2 = 0 \quad \text{or} \quad x^2 = 1 \] Thus, \[ x = 0, \quad x = 1, \quad x = -1 \] ### Step 8: Consider the Given Constraints The problem states \(0 < |x| < \sqrt{3}\). Therefore, the valid solutions are: \[ x = 1 \quad \text{and} \quad x = -1 \] ### Conclusion Thus, the number of values of \(x\) that satisfy the equation is: \[ \boxed{2} \]

To solve the equation \[ \sin^{-1}\left(x^2 - \frac{x^4}{3} + \frac{x^6}{9} + \ldots\right) + \cos^{-1}\left(x^4 - \frac{x^8}{3} + \frac{x^{12}}{9} + \ldots\right) = \frac{\pi}{2} \] where \(0 < |x| < \sqrt{3}\), we can follow these steps: ...
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