Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa

The number of common tangents of the circles \mathrm{x^2+y^2-2 x-1=0} and \mathrm{x^2+y^2-2 y-7=0} is

Option: 1

2


Option: 2

1


Option: 3

3


Option: 4

4


Answers (1)

best_answer

\mathrm{\text { Centre of } 1^{\text {st }} \text { circle }=(1,0) \text {, radius }=\sqrt{1+0+1}=\sqrt{2}}

Centre of 2nd circle = (0, 1), radius\mathrm{=\sqrt{0+1+7}=2 \sqrt{2}} Distance between centres of two circles

\mathrm{=\sqrt{(1-0)^2+(0-1)^2}=\sqrt{2}}

\mathrm{\text { Difference of radii }=2 \sqrt{2}-\sqrt{2}=\sqrt{2}=\text { distance between centres}}One circle touches internally to other circle, so there is only one common tangent to both.

Posted by

Irshad Anwar

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

BTech aspirant from north-east or UT? Apply for CSAB NEUT counselling 2025 today
anam-khan

JoSAA round 2 cut-off 2025 out; BTech closing ranks for top engineering courses at IITs
anam-khan

Goa Engineering Admission 2025: 1,415 eligible for BE seats; merit list on June 27

Latest Question