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The number of ordered pairs (alpha , bet...

The number of ordered pairs `(alpha , beta )` , where ` alpha , beta in [0,2pi]` satisfying ` log_(2 sec x )(beta^(2)-6beta+10)=log_(3)| cos alpha |` is

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To solve the problem, we need to find the number of ordered pairs \((\alpha, \beta)\) such that: \[ \log_{2}(\sec x)(\beta^{2} - 6\beta + 10) = \log_{3}|\cos \alpha| \] where \(\alpha, \beta \in [0, 2\pi]\). ### Step 1: Simplifying the logarithmic equation From the equation, we can equate the arguments of the logarithms: \[ 2^{\log_{2}(\sec x)} = 3^{\log_{3}|\cos \alpha|} \] This simplifies to: \[ \sec x(\beta^{2} - 6\beta + 10) = |\cos \alpha| \] ### Step 2: Analyzing the secant function The secant function, \(\sec x\), is defined as \( \sec x = \frac{1}{\cos x} \). Thus, we can rewrite the equation as: \[ \frac{1}{\cos x}(\beta^{2} - 6\beta + 10) = |\cos \alpha| \] ### Step 3: Setting bounds for \(|\cos \alpha|\) Since \(|\cos \alpha|\) can take values in the range \([0, 1]\), we have: \[ 0 < \frac{1}{\cos x}(\beta^{2} - 6\beta + 10) \leq 1 \] This implies: \[ 0 < \beta^{2} - 6\beta + 10 \leq \cos x \] ### Step 4: Finding the discriminant of the quadratic Next, we need to analyze the quadratic \( \beta^{2} - 6\beta + 10 \). First, we find its discriminant: \[ D = b^{2} - 4ac = 6^{2} - 4 \cdot 1 \cdot 10 = 36 - 40 = -4 \] Since the discriminant is negative, the quadratic does not intersect the x-axis and is always positive. Therefore, \( \beta^{2} - 6\beta + 10 > 0 \) for all \(\beta\). ### Step 5: Setting the upper bound Next, we need to satisfy the condition: \[ \beta^{2} - 6\beta + 10 \leq 1 \] This leads to: \[ \beta^{2} - 6\beta + 9 \leq 0 \] Factoring gives: \[ (\beta - 3)^{2} \leq 0 \] The only solution to this inequality is: \[ \beta - 3 = 0 \implies \beta = 3 \] ### Step 6: Finding values of \(\alpha\) Now substituting \(\beta = 3\) back into the equation: \[ \beta^{2} - 6\beta + 10 = 3^{2} - 6 \cdot 3 + 10 = 9 - 18 + 10 = 1 \] Thus, we have: \[ |\cos \alpha| = 1 \] The values of \(\alpha\) that satisfy this condition are: \[ \alpha = 0, \pi, 2\pi \] ### Step 7: Counting the ordered pairs We have found that \(\beta = 3\) and the possible values of \(\alpha\) are \(0\), \(\pi\), and \(2\pi\). Therefore, the ordered pairs \((\alpha, \beta)\) are: 1. \((0, 3)\) 2. \((\pi, 3)\) 3. \((2\pi, 3)\) Thus, the total number of ordered pairs \((\alpha, \beta)\) is: \[ \boxed{3} \]
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