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If the area bounded by y = ||x|^(2) - 4|...

If the area bounded by `y = ||x|^(2) - 4|x| + 3||` and the x-axis from `x = 1` to `x = 3` is `p/q` (where, p & q are coprime) then the value of `p + q ` is

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To solve the problem of finding the area bounded by the curve \( y = ||x|^2 - 4|x| + 3| \) and the x-axis from \( x = 1 \) to \( x = 3 \), we will follow these steps: ### Step 1: Simplify the Expression Inside the Modulus First, we simplify the expression inside the modulus: \[ f(x) = |x^2 - 4|x| + 3| \] Since we are interested in the interval from \( x = 1 \) to \( x = 3 \), we note that for \( x \geq 0 \), \( |x| = x \). Thus, we can rewrite the function as: \[ f(x) = |x^2 - 4x + 3| \] ### Step 2: Factor the Quadratic Next, we factor the quadratic: \[ x^2 - 4x + 3 = (x - 1)(x - 3) \] The roots of the quadratic are \( x = 1 \) and \( x = 3 \). ### Step 3: Determine the Sign of the Quadratic in the Interval We need to determine the sign of \( x^2 - 4x + 3 \) in the interval \( [1, 3] \): - At \( x = 1 \): \( f(1) = 0 \) - At \( x = 2 \): \( f(2) = 2^2 - 4 \cdot 2 + 3 = 1 \) (positive) - At \( x = 3 \): \( f(3) = 0 \) Since the quadratic opens upwards and is negative between its roots, we find that: \[ x^2 - 4x + 3 < 0 \quad \text{for } x \in (1, 3) \] Thus, in the interval \( [1, 3] \), we have: \[ f(x) = -(x^2 - 4x + 3) = -x^2 + 4x - 3 \] ### Step 4: Set Up the Integral for Area The area \( A \) bounded by the curve and the x-axis from \( x = 1 \) to \( x = 3 \) can be calculated using the integral: \[ A = \int_{1}^{3} -(-x^2 + 4x - 3) \, dx = \int_{1}^{3} (x^2 - 4x + 3) \, dx \] ### Step 5: Evaluate the Integral Now we compute the integral: \[ A = \int_{1}^{3} (x^2 - 4x + 3) \, dx \] Calculating the integral: \[ = \left[ \frac{x^3}{3} - 2x^2 + 3x \right]_{1}^{3} \] Calculating at the upper limit \( x = 3 \): \[ = \frac{3^3}{3} - 2(3^2) + 3(3) = 9 - 18 + 9 = 0 \] Calculating at the lower limit \( x = 1 \): \[ = \frac{1^3}{3} - 2(1^2) + 3(1) = \frac{1}{3} - 2 + 3 = \frac{1}{3} + 1 = \frac{4}{3} \] Now, substituting the limits into the integral: \[ A = 0 - \frac{4}{3} = \frac{4}{3} \] ### Step 6: Identify \( p \) and \( q \) The area can be expressed as \( \frac{p}{q} \) where \( p = 4 \) and \( q = 3 \). Since 4 and 3 are coprime, we can conclude that: \[ p + q = 4 + 3 = 7 \] ### Final Answer The value of \( p + q \) is \( \boxed{7} \).
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