1plz help me with the other question
if the focus of parabola y2+8=4x coincides with one of the foci of ellipse3x2+by2-12x=0 then eccentricity of ellipse is
a. 1/2 b.1/√2
c.1/4 d. none of these
paragraph question
ABCD is a trapezium in whichAD is perpendicular to the parallel sides. a circle of radius 2 is inscribed in trapezium touching the sides AB, BC,CD,DA at P,Q,R,S respectively. if AB=2 CD, then
the length of side AB is
a. 2 b. 3
c. 4 d. 6
area of triangle PBQ is
a. 16/5 b. 32/5
c 32/√5 d. 16/√5
if BR intersects the circle at T, then BT.BR is equal to
a0 4√2 b. 16
c. 8√2 d. 8
plz help me wid these questions plz show the working also
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7 Answers
1357if the focus of parabola y2+8=4x coincides with one of the foci of ellipse3x2+by2-12x=0 then eccentricity of ellipse is
a. 1/2 b.1/√2
c.1/4 d. none of these
ellipse is 3(x-2)2+by2=12
that is X2/4+b2Y2/12 shifting origin to (2,0)
parabola is y2=4(x-2)
in new coordinates Y2=4X
focus of parabola (1,0)
focus of ellipse is (ae,0) that is (2e,0)
2e=1 e=1/2
1y=4x-8
=4(x-2)
represents parabola with vertex at 2,0 and focus 3,0
ellipse 3x2+by2-12x=0
3(x2-4x+4) -12 + b2 =0 (Adding and subtracting 12)
3(x-2)2 + b2 =12
focus of this ellipse
=
2+2e,o
which isequal to focus of parabola
2+2e=3
e=1/2
solving the other.........
