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If the lines p(p^(2)+1)x-y+q=0 and (p^(2...

If the lines `p(p^(2)+1)x-y+q=0` and `(p^(2)+1)^(2)x+(p^(2)+1)y+2q=0` are perpendicular to the same line, then the value of p is

A

(a) 1

B

(b) `-1`

C

(c) 2

D

(d) `-2`

Text Solution

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The correct Answer is:
To solve the problem, we need to find the value of \( p \) such that the two given lines are perpendicular to the same line, which implies that they are parallel to each other. ### Step-by-step Solution: 1. **Identify the equations of the lines:** The first line \( L_1 \) is given by: \[ p(p^2 + 1)x - y + q = 0 \] The second line \( L_2 \) is given by: \[ (p^2 + 1)^2 x + (p^2 + 1)y + 2q = 0 \] 2. **Rearranging the equations to find slopes:** We need to express both lines in the slope-intercept form \( y = mx + c \). - For line \( L_1 \): \[ y = p(p^2 + 1)x + q \] The slope \( m_1 \) of line \( L_1 \) is: \[ m_1 = p(p^2 + 1) \] - For line \( L_2 \): Rearranging gives: \[ (p^2 + 1)y = -(p^2 + 1)^2 x - 2q \] Dividing by \( (p^2 + 1) \) (assuming \( p^2 + 1 \neq 0 \)): \[ y = -\frac{(p^2 + 1)^2}{(p^2 + 1)}x - \frac{2q}{(p^2 + 1)} \] Simplifying gives: \[ y = -(p^2 + 1)x - \frac{2q}{(p^2 + 1)} \] The slope \( m_2 \) of line \( L_2 \) is: \[ m_2 = -(p^2 + 1) \] 3. **Setting the slopes equal:** Since the two lines are parallel, we set their slopes equal: \[ p(p^2 + 1) = -(p^2 + 1) \] 4. **Solving for \( p \):** Rearranging the equation gives: \[ p(p^2 + 1) + (p^2 + 1) = 0 \] Factoring out \( (p^2 + 1) \): \[ (p^2 + 1)(p + 1) = 0 \] This gives us two cases: - \( p^2 + 1 = 0 \) (not possible for real \( p \)) - \( p + 1 = 0 \) which gives \( p = -1 \) 5. **Conclusion:** Thus, the value of \( p \) is: \[ \boxed{-1} \]
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