Get Answers to all your Questions

header-bg qa

If a circle C, whose radius is 3, touches externally the circle,
x^{2}+y^{2}+2x-47y-4=0at the point (2, 2), then the length of the intercept cut by this
circle C, on the x-axis is equal to :

  • Option 1)

    2\sqrt{5}

  • Option 2)

    3\sqrt2

  • Option 3)

    \sqrt5

  • Option 4)

    2\sqrt3

 

Answers (1)

best_answer

As we have learned

Selection formula -

x= \frac{mx_{2}+nx_{1}}{m+n}

y= \frac{my_{2}+ny_{1}}{m+n}

- wherein

If P(x,y) divides the line joining A(x1,y1) and B(x2,y2) in ration m:n

 

 

General form of a circle -

x^{2}+y^{2}+2gx+2fy+c= 0
 

- wherein

centre = \left ( -g,-f \right )

radius = \sqrt{g^{2}+f^{2}-c}

 

S= x^{2}+y^{2}+2gx+2fy+c=0

 

equation of

 C_{1} is (x-5)^{2}+(y-2)^{2}=3^{2} 

x^{2}+y^{2}-10x-4y+20 =0

X- intercept = 2\sqrt (g^{2}-c)= 2\sqrt(25-20)

= 2\sqrt5

 

 

 

 


Option 1)

2\sqrt{5}

This is correct 

Option 2)

3\sqrt2

This is incorrect 

Option 3)

\sqrt5

This is incorrect 

Option 4)

2\sqrt3

This is incorrect 

Posted by

Himanshu

View full answer

JEE Main high-scoring chapters and topics

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