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A tangent and normal are drawn to a curve `y^2=2x` at A(2,2). Tangent cuts x-axis at point T and normal cuts curve again at P . Then find the value of `DeltaATP`

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To solve the problem, we need to find the area of triangle ATP formed by the points A(2, 2), T, and P, where T is the point where the tangent to the curve \(y^2 = 2x\) at point A intersects the x-axis, and P is the point where the normal at A intersects the curve again. ### Step-by-Step Solution: 1. **Find the Tangent Line at Point A(2, 2)**: The equation of the parabola is given by \(y^2 = 2x\). The slope of the tangent at any point \((x_1, y_1)\) on the parabola can be found using the derivative. The derivative of \(y^2 = 2x\) with respect to \(x\) is: \[ 2y \frac{dy}{dx} = 2 \implies \frac{dy}{dx} = \frac{1}{y} \] At point A(2, 2), the slope \(m\) of the tangent is: \[ m = \frac{1}{2} \] The equation of the tangent line at point A can be written using the point-slope form: \[ y - y_1 = m(x - x_1) \implies y - 2 = \frac{1}{2}(x - 2) \] Simplifying this gives: \[ 2y - 4 = x - 2 \implies 2y = x + 2 \implies x - 2y + 2 = 0 \] 2. **Find the Point T where the Tangent Cuts the X-axis**: To find the x-intercept (point T), set \(y = 0\) in the tangent equation: \[ x - 2(0) + 2 = 0 \implies x + 2 = 0 \implies x = -2 \] Therefore, point T is \((-2, 0)\). 3. **Find the Normal Line at Point A(2, 2)**: The slope of the normal line is the negative reciprocal of the tangent slope. Thus, the slope of the normal is: \[ m_{normal} = -2 \] Using the point-slope form for the normal line: \[ y - 2 = -2(x - 2) \] Simplifying this gives: \[ y - 2 = -2x + 4 \implies y = -2x + 6 \] 4. **Find the Point P where the Normal Intersects the Curve Again**: Substitute \(y = -2x + 6\) into the parabola equation \(y^2 = 2x\): \[ (-2x + 6)^2 = 2x \] Expanding this: \[ 4x^2 - 24x + 36 = 2x \implies 4x^2 - 26x + 36 = 0 \] Dividing through by 2: \[ 2x^2 - 13x + 18 = 0 \] Using the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{13 \pm \sqrt{(-13)^2 - 4 \cdot 2 \cdot 18}}{2 \cdot 2} \] \[ = \frac{13 \pm \sqrt{169 - 144}}{4} = \frac{13 \pm 5}{4} \] This gives: \[ x = \frac{18}{4} = \frac{9}{2} \quad \text{and} \quad x = \frac{8}{4} = 2 \] Since \(x = 2\) corresponds to point A, we take \(x = \frac{9}{2}\). Now, substituting \(x = \frac{9}{2}\) back into the normal equation to find \(y\): \[ y = -2\left(\frac{9}{2}\right) + 6 = -9 + 6 = -3 \] Thus, point P is \(\left(\frac{9}{2}, -3\right)\). 5. **Calculate the Area of Triangle ATP**: The area of triangle formed by points A(2, 2), T(-2, 0), and P\(\left(\frac{9}{2}, -3\right)\) can be calculated using the determinant formula: \[ \text{Area} = \frac{1}{2} \left| x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2) \right| \] Substituting the coordinates: \[ = \frac{1}{2} \left| 2(0 - (-3)) + (-2)(-3 - 2) + \frac{9}{2}(2 - 0) \right| \] \[ = \frac{1}{2} \left| 2(3) + (-2)(-5) + \frac{9}{2}(2) \right| \] \[ = \frac{1}{2} \left| 6 + 10 + 9 \right| = \frac{1}{2} \left| 25 \right| = \frac{25}{2} \] Thus, the area of triangle ATP is \(\frac{25}{2}\) square units.
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