Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Circle question

2011 · Shift 2 · Q24
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Advanced
  3. /Mathematics
  4. /Circle
  5. /2011 · Shift 2 · Q24

Circle question

2011 · Shift 2 · Q24

JEE AdvancedMathematicsCircleMCQ+2 / −0.5
The circle passing through the point (-1, 0) and touching the y-axis at (0, 2) also passes through the point.
  1. A
    (−30,0)\left( { - {3 \over 0},0} \right)(−03​,0)
  2. B
    (−52,2)\left( { - {5 \over 2},2} \right)(−25​,2)
  3. C
    (−30, 52)\left( { - {3 \over 0},\,{5 \over 2}} \right)(−03​,25​)
  4. D
    (- 4, 0)
View written solutionFree

Correct answer: D

Step-by-step Solution:

  1. Understand the geometric properties of the circle. The problem states that the circle touches the y-axis at the point (0, 2).

    • For any circle that is tangent to the y-axis at a point (0, k), its center must have the y-coordinate k. So, the center of our circle is of the form C(h, 2).
    • The radius r of the circle is the perpendicular distance from the center (h, 2) to the y-axis (the line x=0). This distance is |h|. So, r = |h|.
  2. Formulate the equation of the circle. The standard equation of a circle with center (h, k) and radius r is: (x−h)2+(y−k)2=r2(x - h)^2 + (y - k)^2 = r^2(x−h)2+(y−k)2=r2 Substituting k = 2 and r = |h| (which means r2=h2r^2 = h^2r2=h2), we get the equation for our specific circle: (x−h)2+(y−2)2=h2(x - h)^2 + (y - 2)^2 = h^2(x−h)2+(y−2)2=h2

  3. Use the given point to find the value of h. The circle passes through the point (-1, 0). We can substitute x = -1 and y = 0 into the circle's equation to solve for h. (−1−h)2+(0−2)2=h2(-1 - h)^2 + (0 - 2)^2 = h^2(−1−h)2+(0−2)2=h2 (h+1)2+(−2)2=h2(h + 1)^2 + (-2)^2 = h^2(h+1)2+(−2)2=h2 Expanding the terms: (h2+2h+1)+4=h2(h^2 + 2h + 1) + 4 = h^2(h2+2h+1)+4=h2 h2+2h+5=h2h^2 + 2h + 5 = h^2h2+2h+5=h2 Subtracting h2h^2h2 from both sides: 2h+5=02h + 5 = 02h+5=0 h=−52h = -{5 \over 2}h=−25​

  4. Write the final equation of the circle. Now we have the parameters of the circle:

    • Center: C(h, k) = (-5/2, 2)
    • Radius: r = |h| = |-5/2| = 5/2 The equation of the circle is: (x−(−5/2))2+(y−2)2=(5/2)2(x - (-5/2))^2 + (y - 2)^2 = (5/2)^2(x−(−5/2))2+(y−2)2=(5/2)2 (x+5/2)2+(y−2)2=254(x + 5/2)^2 + (y - 2)^2 = {25 \over 4}(x+5/2)2+(y−2)2=425​
  5. Check which of the given points lies on the circle. We will substitute the coordinates of each option into the equation of the circle (x+5/2)2+(y−2)2=25/4(x + 5/2)^2 + (y - 2)^2 = 25/4(x+5/2)2+(y−2)2=25/4.

    • A: (−30,0)\left( { - {3 \over 0},0} \right)(−03​,0): This option involves division by zero, which is undefined. The point is not valid.

    • B: (−52,2)\left( { - {5 \over 2},2} \right)(−25​,2): Let's substitute x = -5/2 and y = 2. (−5/2+5/2)2+(2−2)2=02+02=0(-5/2 + 5/2)^2 + (2 - 2)^2 = 0^2 + 0^2 = 0(−5/2+5/2)2+(2−2)2=02+02=0 Since 0≠25/40 \neq 25/40=25/4, this point is not on the circle. In fact, this is the center of the circle.

    • C: (−30, 52)\left( { - {3 \over 0},\,{5 \over 2}} \right)(−03​,25​): Similar to option A, this option is invalid due to division by zero.

    • D: (- 4, 0): Let's substitute x = -4 and y = 0. (−4+5/2)2+(0−2)2(-4 + 5/2)^2 + (0 - 2)^2(−4+5/2)2+(0−2)2 =(−8/2+5/2)2+(−2)2= (-8/2 + 5/2)^2 + (-2)^2=(−8/2+5/2)2+(−2)2 =(−3/2)2+4= (-3/2)^2 + 4=(−3/2)2+4 =94+4= {9 \over 4} + 4=49​+4 =94+164= {9 \over 4} + {16 \over 4}=49​+416​ =254= {25 \over 4}=425​ The result 254{25 \over 4}425​ matches the right side of the equation (r2r^2r2). Therefore, the point (-4, 0) lies on the circle.

Conclusion

The circle passes through the point (-4, 0). So, option D is the correct answer.

PreviousNext

More from Circle

  • The straight line 2x - 3y = 1 divides the circular region x2+y2≤6 into two parts. If S={(2,43​),(25​,43​),(41​−41​),(81​,41​)}…2011 · Numerical
  • Tangents drawn from the point P (1, 8) to the circle x2+y2−6x−4y−11=0 touch the circle at the points A and B. The equation of the cirumcircle of the triangle PAB is2009 · MCQ
  • The centres of two circles C1​ and C2​ each of unit radius are at a distance of 6 units from each other. Let P be the mid point of the line segement joining the centres of C1​ and C2​ and C a circle touching circles C1​…2009 · Numerical
  • A circle C of radius 1 is inscribed in an equilateral triangle PQR. The points of contact of C with the sides PQ, QR, RP are D, E, F, respectively. The line PQ is given by the equation 3​x+y−6=0 and the point D is (233​​,23​)…2008 · MCQ
  • A circle C of radius 1 is inscribed in an equilateral triangle PQR. The points of contact of C with the sides PQ, QR, RP are D, E, F, respectively. The line PQ is given by the equation 3​x+y−6=0 and the point D is (233​​,23​)…2008 · MCQ
  • A circle C of radius 1 is inscribed in an equilateral triangle PQR. The points of contact of C with the sides PQ, QR, RP are D, E, F, respectively. The line PQ is given by the equation 3​x+y−6=0 and the point D is (233​​,23​)…2008 · MCQ
  • Consider L1​:2x+3y+p−3=0L2​:2x+3y+p+3=0 where p is a real number, and C:x2+y2+6x−10y+30=0 STATEMENT-1 : If line L1​ is a…2008 · MCQ
  • Tangents are drawn from the point (17, 7) to the circle x2+y2=169. Statement 1 : The tangents are mutually perpendicular. Statement 2 : The locus of the points from which mutually perpendicular tangents can be drawn to the given circle…2007 · MCQ