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The slope of the normal at the point (at2,2at) of the parabola y2=4ax is
  • a)
    1/t
  • b)
    t
  • c)
    -t
  • d)
    -1/t
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
The slope of the normal at the point (at2,2at) of the parabola y2=4ax ...
Understanding the Parabola
The equation of the parabola is given as y² = 4ax. Here, the focus is at (a, 0) and the directrix is x = -a.
Point on the Parabola
We are examining the point (at², 2at). To verify that this point lies on the parabola, substitute x = at² into the parabola's equation:
- Substitute: (2at)² = 4a(at²)
- Simplifies to: 4a²t² = 4a²t², confirming the point is on the parabola.
Finding the Slope of the Tangent
To find the slope of the tangent at the point (at², 2at):
- Differentiate y² = 4ax implicitly:
- 2y(dy/dx) = 4a
- Hence, dy/dx = 4a/(2y) = 2a/y
- Substitute y = 2at:
- dy/dx = 2a/(2at) = 1/t
Slope of the Normal
The normal line is perpendicular to the tangent. Hence, the slope of the normal is the negative reciprocal of the slope of the tangent:
- Slope of the normal = -1/(slope of the tangent) = -1/(1/t) = -t
Conclusion
Therefore, the slope of the normal at the point (at², 2at) on the parabola y² = 4ax is:
- Correct Answer: c) -t
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Community Answer
The slope of the normal at the point (at2,2at) of the parabola y2=4ax ...
Understanding the Parabola
The equation of the parabola given is y² = 4ax. In this case, a is a constant that determines the width of the parabola.
Point on the Parabola
We have a specific point on the parabola represented by (at², 2at). Here, t is a parameter that can vary.
Finding the Slope of the Tangent
1. To find the slope of the tangent at the given point (at², 2at):
- Differentiate y² = 4ax implicitly with respect to x.
- This gives us dy/dx = 2a/y.
- At the point (at², 2at), substituting y = 2at gives:
- dy/dx = 2a/(2at) = a/t.
Slope of the Normal Line
2. The slope of the normal line is the negative reciprocal of the slope of the tangent:
- Slope of normal = -1/(dy/dx).
- Therefore, substituting dy/dx = a/t gives:
- Slope of normal = -t/a.
However, we also need to consider that the slope of the tangent line is actually a/t, so the negative reciprocal becomes -t.
Conclusion
Thus, the slope of the normal at the point (at², 2at) is indeed -t. The correct answer is option 'C' (-t), which is consistent with our calculations and understanding of the relationship between slopes of tangents and normals.
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The slope of the normal at the point (at2,2at) of the parabola y2=4ax isa)1/tb)tc)-td)-1/tCorrect answer is option 'C'. Can you explain this answer? for JEE 2025 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about The slope of the normal at the point (at2,2at) of the parabola y2=4ax isa)1/tb)tc)-td)-1/tCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for JEE 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The slope of the normal at the point (at2,2at) of the parabola y2=4ax isa)1/tb)tc)-td)-1/tCorrect answer is option 'C'. Can you explain this answer?.
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