Qus : 1
2
A point P in the first quadrant, lies on y 2 = 4 a x , a > 0, and keeps a distance of 5a units from its focus. Which of the following points lies on the locus of P?
1
(1,0)
2
(1,1)
3
(0,2)
4
(2,0)
Go to Discussion
Solution
Locus of Point on Parabola
Given: Point on parabola y 2 = 4 a x is at distance 5 a from focus ( a , 0 ) .
Distance Equation:
( x − a ) 2 + y 2 = 25 a 2 ⇒ ( x − a ) 2 + 4 a x = 25 a 2 ⇒ x 2 + 2 a x − 24 a 2 = 0
Solving gives: x = 4 a , y = 4 a
✅ Final Answer:
( 4 a , 4 a )
Qus : 2
3
A circle touches the x–axis and also touches the circle with centre (0, 3) and radius 2. The locus of the centre of the circle is
1
a circle
2
an ellipse
3
a parabola
4
a hyperbola
Go to Discussion
Solution
Qus : 3
2
The two parabolas y 2 = 4 a ( x + c ) and y 2 = 4 b x , a > b > 0 cannot
have a common normal unless
1
c > 2 ( a + b )
2
c > ( a − b )
3
c < 2 ( a − b )
4
c < 2 a − b
Go to Discussion
Solution
Qus : 4
2
Coordinate of the focus of the parabola 4 y 2 + 12 x − 20 y + 67 = 0 is
1
( − 5 4 , 17 2 )
2
( − 17 2 , 5 4 )
3
( − 17 4 , 5 2 )
4
( − 5 2 , 17 4 )
Go to Discussion
Solution
Qus : 5
4
An equilateral triangle is inscribed in the parabola y 2 = x . One vertex of the triangle is at
the vertex of the parabola. The centroid of triangle is
1
(1,0)
2
( √ 2 , 0 )
3
( √ 3 , 0 )
4
( 2 , 0 )
Go to Discussion
Solution
Qus : 6
4
An equilateral triangle is inscribed in the parabola y 2 = 4 a x , such that one of the vertices of the triangle
coincides with the vertex of the parabola. The length of the side of the triangle is:
1
a √ 3
2
2 a √ 3
3
4 a √ 3
4
8 a √ 3
Go to Discussion
Solution
Qus : 7
2
The locus of the mid points of all chords of the parabola y 2 = 4 x
which are drawn through its
vertex, is
1
y 2 = 8 x
2
y 2 = 2 x
3
x 2 + 4 y 2 = 16
4
x 2 = 2 y
Go to Discussion
Solution
Qus : 8
3
If x = 1 is the directrix of the parabola y 2 = k x − 8 , then k is:
1
1 8
2
8
3
4
4
1 4
Go to Discussion
Solution
Qus : 9
4
A normal to the curve x 2 = 4 y passes through the point (1, 2). The distance of the origin from the
normal is
1
√ 2
2
2 √ 2
3
1 √ 2
4
3 √ 2
Go to Discussion
Solution
Qus : 10
2
The equation of the tangent at any point of curve x = a c o s 2 t , y = 2 √ 2 a s i n t with m as its slope is
1
y = m x + a ( m − 1 m )
2
y = m x − a ( m + 1 m )
3
y = m x + a ( a + 1 a )
4
y = a m x + a ( m − 1 m )
Go to Discussion
Solution
Qus : 11
2
The locus of the mid-point of all chords of the parabola y 2 = 4 x which are drawn through its vertex is
1
y 2 = 8 x
2
y 2 = 2 x
3
x 2 + 4 y 2 = 16
4
x 2 = 2 y
Go to Discussion
Solution
Locus of Midpoint of Chords
Given Parabola: y 2 = 4 x
Condition: Chords pass through the vertex ( 0 , 0 )
Let the other end of the chord be ( x 1 , y 1 ) , so the midpoint is:
M = ( x 1 2 , y 1 2 ) = ( h , k )
Since the point lies on the parabola: y 2 1 = 4 x 1
⇒ ( 2 k ) 2 = 4 ( 2 h )
⇒ 4 k 2 = 8 h
⇒ k 2 = 2 h
✅ Locus of midpoints:
y 2 = 2 x
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