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Statement-1: Length of the common chord ...

Statement-1: Length of the common chord of the parabola`y^(2)=8x` and the circle `x^(2)+y^(2)=9` is less than the length of the latusrectum of the parabola.
Statement-2: If vertex of a parabola lies at the point (a. 0) and the directrix is x + a = 0, then the focus of the parabola is at the point (2a, 0).

A

Statement-1 is True, Statement - 2 is true, Statement-2 is a correct explanation for Statement-1`

B

Statement-1 is True, Statement - 2 is true, Statement-2 is not a correct explanation for Statement-5

C

Statement-1 is True, Statement - 2 is False.

D

Statement-1 is True, Statement - 2 is True.

Text Solution

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The correct Answer is:
To solve the problem, we need to analyze both statements one by one. ### Step 1: Analyze Statement 1 **Statement 1:** The length of the common chord of the parabola \(y^2 = 8x\) and the circle \(x^2 + y^2 = 9\) is less than the length of the latus rectum of the parabola. 1. **Find the length of the common chord:** - The equation of the parabola is \(y^2 = 8x\). - The equation of the circle is \(x^2 + y^2 = 9\). - Substitute \(y^2 = 8x\) into the circle's equation: \[ x^2 + 8x = 9 \] - Rearranging gives: \[ x^2 + 8x - 9 = 0 \] - To find the roots, we can use the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\): - Here, \(a = 1\), \(b = 8\), and \(c = -9\). - The discriminant \(D = b^2 - 4ac = 8^2 - 4 \cdot 1 \cdot (-9) = 64 + 36 = 100\). - So, the roots are: \[ x = \frac{-8 \pm 10}{2} = 1 \text{ and } -9 \] - Since we are interested in the positive x-coordinate, we take \(x = 1\). 2. **Find the corresponding y-coordinates:** - Substitute \(x = 1\) back into the parabola's equation: \[ y^2 = 8 \cdot 1 = 8 \implies y = \pm 2\sqrt{2} \] - The points of intersection (common chord) are \((1, 2\sqrt{2})\) and \((1, -2\sqrt{2})\). 3. **Calculate the length of the common chord:** - The length of the common chord is the distance between these two points: \[ \text{Length} = |y_2 - y_1| = |2\sqrt{2} - (-2\sqrt{2})| = 4\sqrt{2} \] 4. **Find the length of the latus rectum of the parabola:** - The formula for the length of the latus rectum of a parabola \(y^2 = 4ax\) is \(4a\). - Here, \(4a = 8\) implies \(a = 2\). - Therefore, the length of the latus rectum is \(8\). 5. **Compare the lengths:** - Length of the common chord: \(4\sqrt{2} \approx 5.66\) - Length of the latus rectum: \(8\) - Since \(4\sqrt{2} < 8\), Statement 1 is **True**. ### Step 2: Analyze Statement 2 **Statement 2:** If the vertex of a parabola lies at the point \((a, 0)\) and the directrix is \(x + a = 0\), then the focus of the parabola is at the point \((2a, 0)\). 1. **Understand the properties of the parabola:** - The vertex is at \((a, 0)\) and the directrix is \(x + a = 0\) or \(x = -a\). - The focus of a parabola is located at a distance \(p\) from the vertex along the axis of symmetry. 2. **Determine the position of the focus:** - The distance from the vertex \((a, 0)\) to the directrix \(x = -a\) is: \[ \text{Distance} = a - (-a) = 2a \] - The focus will be located \(p\) units to the right of the vertex, where \(p = 2a\). - Therefore, the focus is at: \[ (a + 2a, 0) = (3a, 0) \] 3. **Conclusion for Statement 2:** - The statement claims the focus is at \((2a, 0)\), which is incorrect. - Therefore, Statement 2 is **False**. ### Final Conclusion - **Statement 1:** True - **Statement 2:** False

To solve the problem, we need to analyze both statements one by one. ### Step 1: Analyze Statement 1 **Statement 1:** The length of the common chord of the parabola \(y^2 = 8x\) and the circle \(x^2 + y^2 = 9\) is less than the length of the latus rectum of the parabola. 1. **Find the length of the common chord:** - The equation of the parabola is \(y^2 = 8x\). - The equation of the circle is \(x^2 + y^2 = 9\). ...
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