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If the tangents to y^(2)= 2x at 3 points...

If the tangents to `y^(2)= 2x` at 3 points have inclinations `30^(@), 40^(@), 50^(@)` and the ordinates of corresponding points are `y_(1),y_(2),y_(3)` then the ascending order of `y_(1),y_(2),y_(3)` is

A

`y^(1),y_(2),y_(3)`

B

`y_(3),y_(2),y_(1)`

C

`y_(1),y_(3),y_(2)`

D

`y_(3),y_(1),y_(2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the ordinates \( y_1, y_2, y_3 \) corresponding to the tangents to the parabola \( y^2 = 2x \) at the given angles of inclination \( 30^\circ, 40^\circ, \) and \( 50^\circ \). ### Step-by-Step Solution: 1. **Identify the Parabola**: The given equation of the parabola is \( y^2 = 2x \). This can be rewritten in the standard form \( y^2 = 4ax \) where \( a = \frac{1}{2} \). **Hint**: Remember that the standard form of a parabola helps identify its properties. 2. **Find the Slope of the Tangents**: The slope \( m \) of the tangent line at any point on the parabola can be determined from the angle of inclination. The slopes corresponding to the angles \( 30^\circ, 40^\circ, \) and \( 50^\circ \) are: \[ m_1 = \tan(30^\circ) = \frac{1}{\sqrt{3}}, \quad m_2 = \tan(40^\circ), \quad m_3 = \tan(50^\circ) \] **Hint**: Use the tangent function to convert angles into slopes. 3. **Equation of the Tangent**: The equation of the tangent to the parabola \( y^2 = 2x \) at a point \( (x_0, y_0) \) is given by: \[ yy_0 = x + \frac{y_0^2}{2} \] Here, \( y_0 = mx_0 \) where \( m \) is the slope of the tangent. 4. **Express \( y_0 \) in terms of \( m \)**: Rearranging the tangent equation gives: \[ y = mx + \frac{y_0^2}{2y_0} \] Since \( y_0^2 = 2x_0 \), we can substitute \( x_0 = \frac{y_0^2}{2} \) into the equation: \[ y = mx + \frac{y_0}{2} \] 5. **Find the ordinates \( y_1, y_2, y_3 \)**: For each slope, we can find the corresponding ordinates: \[ y_1 = m_1 \cdot \frac{y_1^2}{2}, \quad y_2 = m_2 \cdot \frac{y_2^2}{2}, \quad y_3 = m_3 \cdot \frac{y_3^2}{2} \] Rearranging gives: \[ y_1^2 = 2y_1m_1, \quad y_2^2 = 2y_2m_2, \quad y_3^2 = 2y_3m_3 \] 6. **Solve for \( y_1, y_2, y_3 \)**: We can find \( y_1, y_2, y_3 \) by solving the quadratic equations formed: \[ y_1 = 2m_1, \quad y_2 = 2m_2, \quad y_3 = 2m_3 \] 7. **Determine the Ascending Order**: Since \( m_1 < m_2 < m_3 \) (because \( 30^\circ < 40^\circ < 50^\circ \)), it follows that: \[ y_1 < y_2 < y_3 \] Thus, the ascending order of \( y_1, y_2, y_3 \) is: \[ y_1, y_2, y_3 \] ### Final Answer: The ascending order of \( y_1, y_2, y_3 \) is \( y_1, y_2, y_3 \).
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