Home
Class 12
MATHS
There are two circles C(1) and C(2) touc...

There are two circles `C_(1)` and `C_(2)` touching each other and the coordinate axes, if `C_(1)` is smaller than `C_(2)` and its radius is 2 units, then radius of `C_(2)`, is

A

`6+4sqrt(2)`

B

`2+2sqrt(2)`

C

`3+2sqrt(2)`

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem of finding the radius of the second circle \( C_2 \), we will follow these steps: ### Step 1: Understand the Configuration of the Circles We have two circles \( C_1 \) and \( C_2 \) that are touching each other and also touching the coordinate axes. The radius of the smaller circle \( C_1 \) is given as 2 units. ### Step 2: Set Up the Coordinates Let the radius of the larger circle \( C_2 \) be \( r \). The center of circle \( C_1 \) will be at the point \( (2, 2) \) since it touches both axes. The center of circle \( C_2 \) will be at the point \( (r, r) \). ### Step 3: Calculate the Distance Between the Centers The distance \( OP \) from the origin \( O(0, 0) \) to the center of circle \( C_1 \) is calculated as follows: \[ OP = \sqrt{(2 - 0)^2 + (2 - 0)^2} = \sqrt{4 + 4} = \sqrt{8} = 2\sqrt{2} \] ### Step 4: Calculate the Distance from the Origin to the Center of Circle \( C_2 \) The distance \( OQ \) from the origin \( O(0, 0) \) to the center of circle \( C_2 \) is: \[ OQ = \sqrt{(r - 0)^2 + (r - 0)^2} = \sqrt{r^2 + r^2} = \sqrt{2r^2} = r\sqrt{2} \] ### Step 5: Relate the Distances Since the circles are touching each other, the distance \( OQ \) can be expressed as the sum of the distance \( OP \) and the radii of both circles: \[ OQ = OP + PR + RQ \] Where: - \( PR \) is the radius of circle \( C_1 \) which is 2 units. - \( RQ \) is the radius of circle \( C_2 \) which is \( r \). Thus, we have: \[ r\sqrt{2} = 2\sqrt{2} + 2 + r \] ### Step 6: Rearrange the Equation Rearranging gives: \[ r\sqrt{2} - r = 2\sqrt{2} + 2 \] Factoring out \( r \) from the left side: \[ r(\sqrt{2} - 1) = 2\sqrt{2} + 2 \] ### Step 7: Solve for \( r \) Now, we can solve for \( r \): \[ r = \frac{2\sqrt{2} + 2}{\sqrt{2} - 1} \] ### Step 8: Rationalize the Denominator To rationalize the denominator, multiply the numerator and denominator by \( \sqrt{2} + 1 \): \[ r = \frac{(2\sqrt{2} + 2)(\sqrt{2} + 1)}{(\sqrt{2} - 1)(\sqrt{2} + 1)} = \frac{(2\sqrt{2} + 2)(\sqrt{2} + 1)}{2 - 1} = (2\sqrt{2} + 2)(\sqrt{2} + 1) \] ### Step 9: Expand the Numerator Expanding the numerator: \[ = 2\sqrt{2} \cdot \sqrt{2} + 2\sqrt{2} + 2\cdot\sqrt{2} + 2 = 4 + 4\sqrt{2} + 2 = 6 + 4\sqrt{2} \] ### Final Answer Thus, the radius of the second circle \( C_2 \) is: \[ r = 6 + 4\sqrt{2} \]

To solve the problem of finding the radius of the second circle \( C_2 \), we will follow these steps: ### Step 1: Understand the Configuration of the Circles We have two circles \( C_1 \) and \( C_2 \) that are touching each other and also touching the coordinate axes. The radius of the smaller circle \( C_1 \) is given as 2 units. ### Step 2: Set Up the Coordinates Let the radius of the larger circle \( C_2 \) be \( r \). The center of circle \( C_1 \) will be at the point \( (2, 2) \) since it touches both axes. The center of circle \( C_2 \) will be at the point \( (r, r) \). ...
Promotional Banner

Topper's Solved these Questions

  • CIRCLES

    OBJECTIVE RD SHARMA|Exercise Section I - Solved Mcqs|108 Videos
  • CIRCLES

    OBJECTIVE RD SHARMA|Exercise Section-I (Solved MCQs)|1 Videos
  • CARTESIAN PRODUCT OF SETS AND RELATIONS

    OBJECTIVE RD SHARMA|Exercise Chapter Test|31 Videos
  • COMPLEX NUMBERS

    OBJECTIVE RD SHARMA|Exercise Chapter Test|59 Videos

Similar Questions

Explore conceptually related problems

Two circles C_(1) and C_(2) intersect in such a way that their common chord is of maximum length.The center of C_(1) is (1,2) and its radius is 3 units.The radius of C_(2) is 5 units.If the slope of the common chord is (3)/(4), then find the center of C_(2) .

A circle C_(1), of radius 2 touches both x -axis and y -axis.Another circle C_(1) whose radius is greater than 2 touches circle and both the axes.Then the radius of circle is

The centres of two circles C_(1) and C_(2) each of unit radius are at a distance of 6 unit from each other. Let P be the mid-point of the line segment joining the centres of C_(1) and C_(2) and C be a circle touching circles C_(1) and C_(2) externally. If a common tangent to C_(1) and C passing through P is also a common tangent to C_(2) and C, then the radius of the circle C, is

Let circle c_(1), be inscribed in a square with side length 1. As shown in figure smaller circle c_(1) is inscribed in the lower right corner of the square so that c_(1) is tangent to c_(2) and the two sides of the square then the area of the c_(2) is

The two circles x^(2)+y^(2)=ax and x^(2)+y^(2)=c^(2)(c gt 0) touch each other, if |(c )/(a )| is equal to

AB is the common tangent to the circles C_(1) and C_(2).C_(1) and C_(2) are touching externally at C.AD and DC are two chords of the circle C_(1) and BE and CE are two chords of the circle C_(2) Find the measure of /_ADC+/_BEC

Two circles with centres C_(1),C_(2) and same radius r cut each other orthogonally,then r is

C_(1) is a circle of radius 1 touching the x- and the y-axis.C_(2) is another circle of radius greater than 1 and touching the axes as well as the circle C_(1). Then the radius of C_(2) is 3-2sqrt(2)(b)3+2sqrt(2)3+2sqrt(3)(d) none of these

Let C_(1) and C_(2) be externally tangent circles with radius 2 and 3 respectively.Let C_(1) and C_(2) both touch circle C_(3) internally at point A and B respectively.The tangents to C_(3) at A and B meet at T and TA=4, then radius of circle C_(3) is:

OBJECTIVE RD SHARMA-CIRCLES-Chapter Test
  1. There are two circles C(1) and C(2) touching each other and the coordi...

    Text Solution

    |

  2. The two circles x^2 + y^2 -2x+6y+6=0 and x^2 + y^2 - 5x + 6y + 15 = 0 ...

    Text Solution

    |

  3. The two circles x^(2)+y^(2)-2x-2y-7=0 and 3(x^(2)+y^(2))-8x+29y=0

    Text Solution

    |

  4. The centre of the circle passing through (0, 0) and (1, 0) and touchin...

    Text Solution

    |

  5. The circle x^2+y^2=4 cuts the circle x^2+y^2+2x+3y-5=0 in A and B, The...

    Text Solution

    |

  6. One of the limit point of the coaxial system of circles containing x^(...

    Text Solution

    |

  7. A circle touches y-axis at (0, 2) and has an intercept of 4 units on t...

    Text Solution

    |

  8. The equation of the circle whose one diameter is PQ, where the ordinat...

    Text Solution

    |

  9. The circle x^2 + y^2+ 4x-7y + 12 = 0 cuts an intercept on y-axis equal...

    Text Solution

    |

  10. Prove that the equation of any tangent to the circle x^2+y^2-2x+4y-4=0...

    Text Solution

    |

  11. The angle between the pair of tangents from the point (1, 1/2) to the...

    Text Solution

    |

  12. The intercept on line y = x by circle x^2 + y^2- 2x = 0 is AB. Find eq...

    Text Solution

    |

  13. If 3x+y=0 is a tangent to a circle whose center is (2,-1) , then find ...

    Text Solution

    |

  14. Locus of the middle points of chords of the circle x^2 + y^2 = 16 whic...

    Text Solution

    |

  15. Two tangents to the circle x^2 +y^2=4 at the points A and B meet at P(...

    Text Solution

    |

  16. A tangent is drawn to the circle 2(x^(2)+y^(2))-3x+4y=0 and it touch...

    Text Solution

    |

  17. the length of the chord of the circle x^(2)+y^(2)=25 passing through ...

    Text Solution

    |

  18. If the points A(2, 5) and B are symmetrical about the tangent to the c...

    Text Solution

    |

  19. The equation of the circle of radius 2sqrt(2) whose centre lies on the...

    Text Solution

    |

  20. Prove that the maximum number of points with rational coordinates on a...

    Text Solution

    |

  21. The equation of a circle C is x^(2)+y^(2)-6x-8y-11=0. The number of re...

    Text Solution

    |