Circles
coordinate geometry of circles in the form:
- (x−a)2+(y−b)2=r2
- x2+y2+2gx+2fy+c=0
(excluding problems involving two circles)
Practice questions
- 1The curve C has equation y=x−2x2+x+3. Without using a calculator, find the set of values that y…
- 2Find the gradient function of the curve y=2x2−lnx+c. The curve touches the positive x-axis at point T. Fi…
- 3The radius of a circle increases at a rate of 3 cm s^{-1}. Find, in terms of π, the rate of increase of the area whe…
- 4定积分∫01(2x−x2)dx等于() A. 4π B. 2π C. 4π−1…
- 5已知两定点M(0,1),N(1,2),平面内一动点P到M的距离与P到N的距离之比为2,直线y=kx−1与点P的轨迹交于A,B两点. (…
- 6The equation of a circle is x2+y2+8x−20y−53=0. Find the radius of the circle and the coordinates of its ce…
- 7A circle with centre O passes through the points P(-1,7) and Q(0,8). State the relationship between the perpendicular bi…
- 8Two points A(−3,−6) and B(7,−6) lie on a circle with centre G. The equation of the tangent to the circle at the…
- 9圆C的半径为5,圆心在x轴的负半轴上,且被直线3x+4y+4=0截得的弦长为6,则圆C的方程为() A. x2+y2−2x−3=0…
- 10在平面直角坐标系xOy中,曲线C的参数方程为{y=4sinax=4cosa+2(a为参数),以O为极点,以x轴…
- 11求过A(1,0)与B(0,1)两点,且在x轴上截得的弦长等于6的圆的方程.
- 12A circle, C1, has an equation x2−6x+y2+10y=66. Are the x-axis and y-axis tangents to C1? Explain y…
- 13The equation of a circle C1 is given by the equation x2+y2−4x−8y=0. Find the coordinates of the center an…
- 14已知圆的方程(x−2)2+y2=1,过圆外一点P(3,4)作一条直线与圆交于A,B两点,那么PA⋅PB=…
- 15已知圆心为C的圆过点A(0,−6)和B(1,−5),且圆心在直线l:x−y+1=0上. (1)求圆心为C的圆的标准方程; (2)过点M(2,8)作圆的切线,求切线方程.
- 16A(1, 7) and B(9, 7) lie on a circle C1 with centre P. The line 4y+3x=31 is a normal to the circle and passes th…
- 17点M(0,2)与圆C:(x−a)2+y2=1(a∈R)的位置关系是() A. 点M在圆C内 B. 点M在圆C上 C. 点M在圆C外…
- 18已知圆C:(x+1)2+(y−1)2=1与x轴切于A点,与y轴切于B点,设劣弧A^B的中点为M,则过点M的圆C的切线方程是() A…
- 19从点P(3,−1)向圆x2+y2−4y−5=0作切线PT(T为切点),则∣PT∣等于() A. 5…
- 20Solutions to this question by accurate drawing will not be accepted. The diagram shows an isosceles triangle PQR in whic…
- 21The equation of a circle is x2+y2+2x−8y−8=0. Find the coordinates of the centre, C and the radius of the…
- 22The points P and Q both lie on a circle and have coordinates (−10,15) and (10,0) respectively. The centre of t…
- 23已知圆C1:x2+y2-6x-6=0…
- 24已知三个点A(0,0),B(2,0),C(4,2),则△ABC的外心的纵坐标是() A. 23 B. 3 C. 25…
- 25The lines y=9, y=−1 and 3y=4x+9 are tangents to a circle. The x-coordinate of the centre of the circle is positive…
- 26直线y=2x与圆C:(x−2)2+(y+1)2=14交于A,B两点,则△ACB的面积等于(). A. 235…
- 27在极坐标系中,圆心为(1,2π),且过极点的圆的方程是() A. ρ=2sinθ B. ρ=−2sinθ C. ρ=2cosθ D. ρ=−2cosθ
- 28The equation of a circle, C1, is Find the coordinates of the centre of C1 and its radius. Find the equation of the…
- 29如果方程x2+y2+x+y+k=0表示一个圆,则k的取值范围是() A. k>21 B. 0<k<21 C. k<21…
- 30在平面直角坐标系中,曲线C1的参数方程为{x=−1+5cosαy=−2+5sinα(α为参数).以坐标原点O为极点…
- 31圆x2+y2−mx+y+m=0在x轴上截得的弦长是它在y轴上截得的弦长的2倍,则实数m的值是() A. −6−210 B. −6+210…
- 32过三点A(0,0),B(0,2),C(2,0)的圆M与直线l:kx−y+2−2k=0的位置关系是() A. 相交 B. 相切 C. 相交或相切 D. 相切或相离
- 33直线l:kx−y+1=0被圆x2+y2−4y=0截得的最短弦长为() A. 23 B. 3 C. 22 D. 2
- 34已知O为坐标原点,M(1,2),P是抛物线C:y2=2px(p>0)上的一点,F为其焦点,若点F与双曲线3x2−y2=1的…
- 35已知圆方程C1:f(x,y)=0,点P1(x1,y1)在圆C1上,点P2(x2,y2)不在圆C1上,则方程:f(x,y)−f(x1,y1)−f(x2,y2)=0…
- 36A circle, with centre C, has equation x2+y2−10x−4y+25=0. Find the coordinates of C and the radius of the…
- 37A circle, C1, has equation x2+y2−4x+6y=36. Find the radius and the coordinates of the centre of C1.
- 38方程x2+y2+2x−4y−6=0表示的图形是() A. 以(1,−2)为圆心,11为半径的圆 B. 以(−1,2)为圆心,11为半径的圆 C. 以(−1,2)为圆心,11…
- 39已知圆C1:x2+y2=r2(r>0)与抛物线C2:x2=2py(p>0),点(2,−2)是圆C1与抛物线C2…
- 40在直角坐标系xOy中,曲线C1的方程为y=k∣x∣+2.以坐标原点为极点,x轴正半轴为极轴建立极坐标系,曲线C2的极坐标方程为ρ2+2ρcosθ−3=0…
- 41The diagram shows part of the curve y=2x+4, meeting the x-axis at the point A and the y-axis at the p…
- 42The diagram (not drawn to scale) shows a right-angled triangle PQR in which point P is (5, 4) and point R is (9, 2). Poi…
- 43Point P lies on the curve y=2−xkx2, where k is a constant. The x-coordinate of P is −2. G…
- 44The diagram shows a trapezium with vertices A(6, 8), B, C and D. The sides AB and DC are parallel and angle ABC is 90∘…
- 45已知点(a+1,a−1)在圆x2+y2−2ay−4=0外,则实数a的取值范围为() A. a<1 B. a>1 C. 0<a<1 D. a>51…
- 46In the diagram below, the line OP makes an angle of α∘ with the positive x-axis such that tanα=0.2…
- 47Solutions to this question by accurate drawing will not be accepted. OABC is a trapezium with right angle OAB. T…
- 48The points A(5,7) and B(−11,15) lie on a circle C. The centre of the circle O lies on the line y=−2x−3.…
- 49已知直线l:kx+y−2=0(k∈R)是圆C:x2+y2−6x+2y+6=0的一条对称轴,过点A(0,k)作圆C的一条切线,切点为B,则线段AB的长度为…
- 50圆x2+y2−2x−5=0和圆x2+y2+2x−4y−4=0的交点为A、B,则线段AB的垂直平分线方程为() A. x+y−1=0…
- 51The equation of a circle, C1 is x2+y2−4x+6y−3=0. Find the coordinates of the centre and the radius of C1…
- 52已知圆C的圆心在直线y=x+1上,且圆C与x轴相切,点P(−5,−2)在圆C上,点Q(−4,−5)在圆C外. (1)求圆C的方程; (2)若过点(−2,−4)的…
- 53直线l:mx+y−m−2=0与圆C:(x−3)2+(y−4)2=25交于A,B两点,C为圆心,当∠ACB最小时,直线l的方程是 ___ .
- 54已知圆O:x2+y2=4和圆C:(x−2)2+(y−3)2=1.现给出如下结论,其中正确的是() A. 圆O与圆C有四条公切线 B. 过C且在…
- 55求圆 x2+y2−4x+6y−12=0 的圆心坐标和半径。
- 56It is given that f(x)={4a2−x23x−6afor 0≤x≤2a,for 2a<x<3a,…
- 57The diagram below is not drawn to scale. In the diagram, D, E and F are points on the circle C1. Show that DE is the dia…
- 58The equation of a circle with centre C is x2+y2−8x−2y−152=0. Find the coordinates of C and the radius of the cir…
- 59A tangent to a circle at the point (−3,3) passes through the origin. Find the equation of the normal to the circle at…
- 60A circle, C1, has the equation x2+y2+2x−6y=10. Find the coordinates of the centre and the exact radius of…