हिंदी

Show that the Points (5, 5), (6, 4), (−2, 4) and (7, 1) All Lie on a Circle, and Find Its Equation, Centre and Radius. - Mathematics

Advertisements
Advertisements

प्रश्न

Show that the points (5, 5), (6, 4), (−2, 4) and (7, 1) all lie on a circle, and find its equation, centre and radius.

Advertisements

उत्तर

Let the required equation of the circle be

\[x^2 + y^2 + 2gx + 2fy + c = 0\] ...(1)
It is given that the circle passes through (5, 5), (6, 4), (−2, 4).
∴ \[50 + 10g + 10f + c = 0\] ...(2)
\[52 + 12g + 8f + c = 0\] ...(3)
\[20 - 4g + 8f + c = 0\] ...(4)
Solving (2), (3) and (4):
\[g = - 2, f = - 1, c = 20\]
Thus, the equation of the circle is
\[x^2 + y^2 - 4x - 2y - 20 = 0\]  ...(5)
We see that the point (7, 1) satisfies equation (5).
Hence, the points (5, 5), (6, 4), (−2, 4) and (7, 1) lie on the circle.
Also, centre of the required circle = \[\left( 2, 1 \right)\]
Radius of the required circle = \[\sqrt{4 + 1 + 20} = 5\]
shaalaa.com
Advanced Concept of Circle - Standard Equation of a Circle
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 24: The circle - Exercise 24.2 [पृष्ठ ३२]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 11
अध्याय 24 The circle
Exercise 24.2 | Q 6 | पृष्ठ ३२

संबंधित प्रश्न

Find the equation of the circle with:

Centre (0, −1) and radius 1.


Find the centre and radius of each of the following circles:

(x + 5)2 + (y + 1)2 = 9


Find the centre and radius of each of the following circles:

x2 + y2 − 4x + 6y = 5


Find the centre and radius of each of the following circles:

x2 + y2 − x + 2y − 3 = 0.


Find the equation of the circle whose centre is (1, 2) and which passes through the point (4, 6).


Find the equation of the circle whose centre lies on the positive direction of - axis at a distance 6 from the origin and whose radius is 4.


Find the equation of the circle which has its centre at the point (3, 4) and touches the straight line 5x + 12y − 1 = 0.


Find the equation of the circle which touches the axes and whose centre lies on x − 2y = 3.


Find the equations of the circles touching y-axis at (0, 3) and making an intercept of 8 units on the X-axis.


If the line y = \[\sqrt{3}\] x + k touches the circle x2 + y2 = 16, then find the value of k


Find the equation of the circle having (1, −2) as its centre and passing through the intersection of the lines 3x + y = 14 and 2+ 5y = 18.


If the lines 3x − 4y + 4 = 0 and 6x − 8y − 7 = 0 are tangents to a circle, then find the radius of  the circle.


Show that the point (xy) given by  \[x = \frac{2at}{1 + t^2}\] and \[y = a\left( \frac{1 - t^2}{1 + t^2} \right)\]  lies on a circle for all real values of t such that \[- 1 \leq t \leq 1\] where a is any given real number.

 


If the line 2x − y + 1 = 0 touches the circle at the point (2, 5) and the centre of the circle lies on the line x + y − 9 = 0. Find the equation of the circle.


Find the equation of the circle passing through the points:

(5, 7), (8, 1) and (1, 3)


Find the equation of the circle which passes through (3, −2), (−2, 0) and has its centre on the line 2x − y = 3.


Find the equation of the circle which circumscribes the triangle formed by the lines 2x + y − 3 = 0, x + y − 1 = 0 and 3x + 2y − 5 = 0


Prove that the centres of the three circles x2 y2 − 4x − 6y − 12 = 0, x2 + y2 + 2x + 4y − 10 = 0 and x2 + y2 − 10x − 16y − 1 = 0 are collinear.


Find the equation to the circle which passes through the points (1, 1) (2, 2) and whose radius is 1. Show that there are two such circles.


Find the equation of the circle concentric with x2 + y2 − 4x − 6y − 3 = 0 and which touches the y-axis.


The sides of a square are x = 6, x = 9, y = 3 and y = 6. Find the equation of a circle drawn on the diagonal of the square as its diameter.


Find the equation of the circle whose diameter is the line segment joining (−4, 3) and (12, −1). Find also the intercept made by it on y-axis.


The line 2x − y + 6 = 0 meets the circle x2 + y2 − 2y − 9 = 0 at A and B. Find the equation of the circle on AB as diameter.


Find the equations of the circles which pass through the origin and cut off equal chords of \[\sqrt{2}\] units from the lines y = x and y = − x.


Write the length of the intercept made by the circle x2 + y2 + 2x − 4y − 5 = 0 on y-axis.


If the radius of the circle x2 + y2 + ax + (1 − a) y + 5 = 0 does not exceed 5, write the number of integral values a.


Write the area of the circle passing through (−2, 6) and having its centre at (1, 2).


If 2x2 + λxy + 2y2 + (λ − 4) x + 6y − 5 = 0 is the equation of a circle, then its radius is


The equation x2 + y2 + 2x − 4y + 5 = 0 represents


If the equation (4a − 3) x2 + ay2 + 6x − 2y + 2 = 0 represents a circle, then its centre is ______. 


If the point (2, k) lies outside the circles x2 + y2 + x − 2y − 14 = 0 and x2 + y2 = 13 then k lies in the interval


The equation of the circle passing through the origin which cuts off intercept of length 6 and 8 from the axes is


The equation of the circle which touches the axes of coordinates and the line \[\frac{x}{3} + \frac{y}{4} = 1\] and whose centres lie in the first quadrant is x2 + y2 − 2cx − 2cy + c2 = 0, where c is equal to


If (−3, 2) lies on the circle x2 + y2 + 2gx + 2fy + c = 0 which is concentric with the circle x2 + y2 + 6x + 8y − 5 = 0, then c =


Equation of the circle through origin which cuts intercepts of length a and b on axes is


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×