Ask Questions, Get Answers
Menu
X
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
15 Test Series
CBSE XII
Math
JEEMAIN
Math
Physics
Chemistry
Practice Test Series
CBSE XI
Math
NEET
Physics
Chemistry
Biology - XII
Biology - XI
Olympiad class V
Math - 5 Test Series
Olympiad class VI
Math - 5 Test Series
studyplans
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
15 Test Series
CBSE XII
Math
JEEMAIN
Math
Physics
Chemistry
Practice Test Series
CBSE XI
Math
NEET
Physics
Chemistry
Biology - XII
Biology - XI
Olympiad class V
Math - 5 Test Series
Olympiad class VI
Math - 5 Test Series
mobile
exams
ask
sample papers
tutors
pricing
login
X
ASK
Home
>>
JEEMAIN and NEET
>>
Mathematics
>>
Class11
>>
Coordinate Geometry
The equation of common tangent to the curves $y^2=8x$ and $xy=-1$ is
$\begin{array}{1 1}(A)\;3y=9x+2 \\(B)\;y=2x+1 \\(C)\;2y=x+8 \\(D)\;y=x+2 \end{array}$
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
medium
Share
asked
Apr 10, 2014
by
meena.p
retagged
Sep 27, 2014
by
sharmaaparna1
Please
log in
or
register
to add a comment.
Please
log in
or
register
to answer this question.
1 Answer
Any tangent to $y^2=8x$ is
$Y=mx+2/m$
it should also be tangent two $xy=-1$
$\bigg(mx+\large\frac{2}{m}\bigg)$$x=-1$
$m^2x^2+2x+m=0$
$D=0 => 4-4(+m)(m^2)=0$
$\qquad= m^3=+1$
=>$m=1$
So, the equation is $y=x+2$
Hence D is the correct answer.
answered
Apr 10, 2014
by
meena.p
Please
log in
or
register
to add a comment.
Related questions
Find the equation of common tangent to the parabola $y^2=4x$ and $x^2=4y$?
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
q52
medium
asked
Feb 5, 2014
by
sreemathi.v
1
answer
Find the equation of straight line touching both $x^2+y^2=2$ and $y^2=8x$.
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
q50
medium
asked
Feb 5, 2014
by
sreemathi.v
1
answer
The common tangent to the parabola $y^2=4ax$ and $x^2=4ay$ is
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
medium
asked
Apr 9, 2014
by
meena.p
1
answer
The normal to the parabola $y^2=8x$ at the point $(2,4)$ meets the parabola again at the point.
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
difficult
asked
Apr 9, 2014
by
meena.p
1
answer
P is a point, two tangents are drawn from it to the parabola $y^2=4x$ such that the slope of one tangent is three times the slope of the other. The locus of P is
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
medium
asked
Apr 10, 2014
by
meena.p
1
answer
The angle between the tangent drawn from the point $(1,4)$ to the parabola $y^2=4x$ is
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
difficult
asked
Apr 10, 2014
by
meena.p
1
answer
Find the length of tangent,subtangent,normal and subnormal to $y^2=4ax$ at $(at^2,2at)$
jeemain
math
class11
coordinate-geometry-conic -sections
parabola
ch11
q67
difficult
asked
Feb 6, 2014
by
sreemathi.v
1
answer
Ask Question
Tag:
Math
Phy
Chem
Bio
Other
SUBMIT QUESTION
►
Please Wait
Take Test
JEEMAIN Crash Practice
15 Test Series
NEET Crash Practice
15 Test Series
JEEMAIN
350+ TESTS
NEET
320+ TESTS
CBSE XI MATH
50+ TESTS
CBSE XII MATH
80+ TESTS
...