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Let the maximum and minimum value of the...

Let the maximum and minimum value of the expression `2 cos^(2) theta + cos theta + 1` is M and m respectively, then the value of `[M/m]` is (where [.] is the greatest integer function)

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To find the maximum and minimum values of the expression \( f(\theta) = 2 \cos^2 \theta + \cos \theta + 1 \), we will follow these steps: ### Step 1: Rewrite the Expression First, we can rewrite the expression in terms of \( x = \cos \theta \). The range of \( x \) is \([-1, 1]\). \[ f(x) = 2x^2 + x + 1 \] ### Step 2: Find the Derivative Next, we need to find the derivative of \( f(x) \) to locate the critical points. \[ f'(x) = \frac{d}{dx}(2x^2 + x + 1) = 4x + 1 \] ### Step 3: Set the Derivative to Zero To find the critical points, we set the derivative to zero: \[ 4x + 1 = 0 \] Solving for \( x \): \[ 4x = -1 \implies x = -\frac{1}{4} \] ### Step 4: Evaluate the Function at Critical Points and Endpoints Now we evaluate \( f(x) \) at the critical point \( x = -\frac{1}{4} \) and at the endpoints \( x = -1 \) and \( x = 1 \). 1. **At \( x = -\frac{1}{4} \)**: \[ f\left(-\frac{1}{4}\right) = 2\left(-\frac{1}{4}\right)^2 + \left(-\frac{1}{4}\right) + 1 = 2\left(\frac{1}{16}\right) - \frac{1}{4} + 1 = \frac{1}{8} - \frac{2}{8} + \frac{8}{8} = \frac{7}{8} \] 2. **At \( x = -1 \)**: \[ f(-1) = 2(-1)^2 + (-1) + 1 = 2(1) - 1 + 1 = 2 \] 3. **At \( x = 1 \)**: \[ f(1) = 2(1)^2 + (1) + 1 = 2(1) + 1 + 1 = 4 \] ### Step 5: Determine Maximum and Minimum Values From the evaluations: - \( f\left(-\frac{1}{4}\right) = \frac{7}{8} \) - \( f(-1) = 2 \) - \( f(1) = 4 \) Thus, the maximum value \( M = 4 \) and the minimum value \( m = \frac{7}{8} \). ### Step 6: Calculate \( \left\lfloor \frac{M}{m} \right\rfloor \) Now we calculate \( \frac{M}{m} \): \[ \frac{M}{m} = \frac{4}{\frac{7}{8}} = 4 \cdot \frac{8}{7} = \frac{32}{7} \approx 4.5714 \] Taking the greatest integer function: \[ \left\lfloor \frac{M}{m} \right\rfloor = 4 \] ### Final Answer The value of \( \left\lfloor \frac{M}{m} \right\rfloor \) is \( \boxed{4} \). ---
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