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Let the lengths of the altitudes from th...

Let the lengths of the altitudes from the vertices `A(-1, 1), B(5, 2), C(3, -1)` of `DeltaABC` are `p_(1), p_(2), p_(3)` units respectively then the value of `(((1)/(p_(1)))^(2)+((1)/(p_(3)))^(2))/(((1)/(p_(2)))^(2))` is equal to

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To solve the problem, we need to find the value of \[ \frac{\left(\frac{1}{p_1}\right)^2 + \left(\frac{1}{p_3}\right)^2}{\left(\frac{1}{p_2}\right)^2} \] where \( p_1, p_2, p_3 \) are the lengths of the altitudes from the vertices \( A(-1, 1), B(5, 2), C(3, -1) \) of triangle \( ABC \). ### Step 1: Calculate the lengths of the sides of triangle ABC. 1. **Length of side AB**: \[ AB = \sqrt{(5 - (-1))^2 + (2 - 1)^2} = \sqrt{(5 + 1)^2 + (2 - 1)^2} = \sqrt{6^2 + 1^2} = \sqrt{36 + 1} = \sqrt{37} \] 2. **Length of side BC**: \[ BC = \sqrt{(3 - 5)^2 + (-1 - 2)^2} = \sqrt{(-2)^2 + (-3)^2} = \sqrt{4 + 9} = \sqrt{13} \] 3. **Length of side CA**: \[ CA = \sqrt{(3 - (-1))^2 + (-1 - 1)^2} = \sqrt{(3 + 1)^2 + (-2)^2} = \sqrt{4^2 + 2^2} = \sqrt{16 + 4} = \sqrt{20} = 2\sqrt{5} \] ### Step 2: Calculate the area of triangle ABC using the determinant formula. The area \( \Delta \) of triangle ABC can be calculated using the formula: \[ \Delta = \frac{1}{2} \left| x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2) \right| \] Substituting the coordinates: \[ \Delta = \frac{1}{2} \left| -1(2 - (-1)) + 5((-1) - 1) + 3(1 - 2) \right| \] \[ = \frac{1}{2} \left| -1(3) + 5(-2) + 3(-1) \right| = \frac{1}{2} \left| -3 - 10 - 3 \right| = \frac{1}{2} \left| -16 \right| = 8 \] ### Step 3: Relate the area to the altitudes. Using the formula for the area in terms of the base and height: \[ \Delta = \frac{1}{2} \times \text{base} \times \text{height} \] Thus, we can express the altitudes as: \[ p_1 = \frac{2\Delta}{BC}, \quad p_2 = \frac{2\Delta}{CA}, \quad p_3 = \frac{2\Delta}{AB} \] Calculating the altitudes: - For \( p_1 \): \[ p_1 = \frac{2 \times 8}{\sqrt{13}} = \frac{16}{\sqrt{13}} \] - For \( p_2 \): \[ p_2 = \frac{2 \times 8}{2\sqrt{5}} = \frac{16}{2\sqrt{5}} = \frac{8}{\sqrt{5}} \] - For \( p_3 \): \[ p_3 = \frac{2 \times 8}{\sqrt{37}} = \frac{16}{\sqrt{37}} \] ### Step 4: Substitute the values into the expression. Now substituting \( p_1, p_2, p_3 \) into the expression: \[ \frac{\left(\frac{1}{p_1}\right)^2 + \left(\frac{1}{p_3}\right)^2}{\left(\frac{1}{p_2}\right)^2} = \frac{\left(\frac{\sqrt{13}}{16}\right)^2 + \left(\frac{\sqrt{37}}{16}\right)^2}{\left(\frac{\sqrt{5}}{8}\right)^2} \] Calculating each term: \[ = \frac{\frac{13}{256} + \frac{37}{256}}{\frac{5}{64}} = \frac{\frac{50}{256}}{\frac{5}{64}} = \frac{50}{256} \times \frac{64}{5} = \frac{50 \times 64}{256 \times 5} = \frac{3200}{1280} = \frac{8}{4} = 2 \] ### Final Answer: The value of \[ \frac{\left(\frac{1}{p_1}\right)^2 + \left(\frac{1}{p_3}\right)^2}{\left(\frac{1}{p_2}\right)^2} = 2 \]
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