Coordinate Geometry Questions (181)

If pair of variable straight lines $x^2+4y^2+\alpha xy=0$ ($\alpha$ real) cuts the ellipse $x^2+4y^2=4$ at $A$ and $B$, then the locus of point of intersection of tangents at $A$ and $B$ of ellipse is
Let $P$ be any point on $x-y+3=0$ and $A=(3,4)$. If the family of lines $(3\sec\theta+5\csc\theta)x+(7\sec\theta-3\csc\theta)y+11(\sec\theta-\csc\theta)=0$ are concurrent at $B$ for all permissible $\theta$, then max value of $|PA-PB|$ is
The equation of the circle which passes through $(1,0)$, $(0,1)$ and has smallest possible radius is
If a circle of radius $r$ passes through origin and meets axes at $A$ and $B$ such that $(3,4)$ lies on $\overline{AB}$, then $r$ is
A line $L: 2x-y+5=0$ is tangent to the hyperbola $H\equiv\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ such that the foot of perpendicular from the foci of $H$ on $L$ is $\left(\frac{\sqrt{3}-2\sqrt{5}}{\sqrt{5}},\frac{2\sqrt{3}+\sqrt{5}}{\sqrt{5}}\right)$. If $H$ intersects an ellipse $E\equiv\frac{x^2}{25}+\frac{y^2}{\lambda^2}=1$ orthogonally, then eccentricity of $E$ is
The equation of the circle which passes through origin and cuts off intercepts $a$ and $b$ from axes is
On the hyperbola $y^2 - x^2 = 1$, consider a point $P$ with abscissa $n$ (integer). Let $d_n$ be the shortest distance from $P$ to the line $y = x$. Then $\lim_{n \to \infty} n \cdot d_n$ equals
The equation of the line passing through the intersection of lines $x-y-1=0$ and $2x-3y+1=0$, and through $(1,2)$, is
Let points $S_1$ and $S_2$ (lying on positive $x$-axis) be the foci of $\dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}=1$ and $\dfrac{x^2}{a^2}-\dfrac{y^2}{c^2}=\dfrac{1}{4}$. If a point of intersection is equidistant from $S_1$ and $S_2$ and $a:b=\sqrt{7}:\sqrt{6}$, then $a:c$ is
The eccentricity of conic $\sqrt{(x-1)^2+y^2}+\sqrt{(x+1)^2+y^2}=4$ is
TP and TQ are tangents to a parabola and $p_1$, $p_2$, $p_3$ are the lengths of perpendiculars from $P$, $T$, $Q$ respectively on any tangent to the parabola. Then $p_1$, $p_2$, $p_3$ are in
The area of smaller region bounded by the curve $9x^2+4y^2-36x+16y+16=0$ and the line $3x+2y=8$ is
Given lines $\dfrac{x}{a}+\dfrac{y}{b}=1$ and $ax+by=1$ are two variable lines, $a$ and $b$ being parameters connected by $a^2+b^2=ab$. The locus of the point of intersection is
Parabola $y^2=4a(x-c_1)$ and $x^2=4a(y-c_2)$ touch each other where $c_1,c_2$ are variables. Then locus of their point of contact is
Statement-I: A variable line drawn through a fixed point cuts the coordinate axes at A and B. The locus of mid-point of AB is a circle. Statement-II: Through 3 non-collinear points in a plane, only one circle can be drawn.
The point $(2,1)$ is translated parallel to $L:x-y=4$ by $2\sqrt3$ units. If new point $Q$ is in the third quadrant, equation of line through $Q$ perpendicular to $L$ is
Let $A$, $B$, $C$ be 3 points on the parabola $y^2=4x$. Let $D$, $E$, $F$ be midpoints of $AB$, $BC$ and $AC$ respectively. If $G$ is the centroid of $\triangle DEF$ and normals to the parabola at $A$, $B$ and $C$ are concurrent at $H(5,1)$, then slope of the line $GH$ is
Area of triangle formed by tangents from $(x_1,y_1)$ to $y^2=4ax$ and the chord of contact is
The equation of the straight line passing through $(1,2)$ with slopes satisfying $m^2-m-2=0$ are
Consider: I) General form $ax+by+c=0$ ($a,b,c\in\mathbb{R}$) always represents a straight line. II) A line $ax+by+1=0$ is such that algebraic sum of perpendiculars from $(x_i,y_i)$ $(i=1,2,\ldots,n)$ is zero, then line always passes through a fixed point $\left(\bar{x},\bar{y}\right)$ where $\bar{x}=\frac{\sum x_i}{n}$ and $\bar{y}=\frac{\sum y_i}{n}$.
The equation of an asymptote to the hyperbola $18x^2+27xy-4y^2=0$
If the circles $x^2+y^2+10\alpha x+\beta y+\alpha=0$ and $x^2+y^2-5\alpha x+\gamma y-1=0$ intersect in two distinct points $A$ and $B$, then the line $15x+\delta y-\alpha=0$ passes through $A$ and $B$ for
If a straight line having negative slope passing through the point $P=(8,2)$ meets the $x$-axis at $A$ and $y$-axis at $B$ respectively. Then the minimum value of $OA+OB$ ($O$ being origin) is
A tangent to ellipse $\dfrac{x^2}{4}+\dfrac{y^2}{b^2}=1$ $(0<b<2)$ at point $P$ in first quadrant meets $x$-axis at $A$ and $y$-axis at $B$. If $O$ is origin and $\triangle OAB$ has minimum area $\sqrt{2}$ sq. units, then $b=$
Circles $C_1:x^2+y^2=625$, $C_2:(x-a)^2+y^2=576$, $a\in(1,49)$. Point $P$ is on both circles with $\angle QPR=\cos^{-1}\!\left(\dfrac{\sqrt{481}}{25}\right)$ ($Q,R$ are centers). Length of common tangent $=\sqrt{1295}$. Common chord length is
Sum of length of all the common tangents of the circles $x^2+y^2-2x-8y+15=0$ and $x^2+y^2-6x-12y+43=0$ is
Let $H_n: \dfrac{x^2}{1+n}-\dfrac{y^2}{3+n}=1$, $n\in\mathbb{N}$. Let $k$ be the smallest even value of $n$ such that eccentricity of $H_k$ is rational. If $\ell$ is the length of the latus rectum of $H_k$, then $21\ell$ is equal to
The eccentricity of ellipse $3x^2+4y^2=12$ is changed at the rate of $0.1$/sec. The time in seconds such that the ellipse becomes an auxiliary circle is
Let $\triangle PQR$ inscribed in parabola $y^2=4ax$ where $P=(at_1^2,2at_1)$, $Q=(at_2^2,2at_2)$, $R=(at_3^2,2at_3)$. The orthocentre of $\triangle PQR$ is
The number of common tangents to circles $x^2+y^2-4x-6y-12=0$ and $x^2+y^2+6x+18y+26=0$ is
If the latus rectum of hyperbola $16x^2-9y^2=144$ is 8, its eccentricity is
Circle $x^2+y^2=r^2$ meets ellipse $16x^2+25y^2=400$; $4<r<5$. Common tangent (slope $m>0$) in 2nd quadrant meets axes at $P$, $Q$. Area of $\triangle OPQ$ (O=origin) is minimum. Then $m$ is
Two sides of a triangle have combined equation $x^2-3y^2-2xy+8y-4=0$. The third side passes through $(-5,1)$ and the origin is interior. If the range of slope of the third line is $(a,b)$, then $\dfrac{a+\frac{1}{b^2}}{4}$ is
If $P(6,1)$ be the orthocentre of the triangle whose vertices are $A(5,-2)$, $B(8,3)$ and $C(h,k)$, then the point $C$ lies on the circle
For a circle with radius r and angle parameters, find the area of triangle ABC where cos(a) = 1/2, and BD = 2 cot(q/2) = 2 cot(π/2 − a) = 2 tan(a), with AC = 3 and BD = 2√15.
Number of possible ordered pair(s) (x, y) of all positions of point P on AB so that area of the rectangle PDOC is 30 sq. units is:
The sum of the coordinates of the point P if PDOC is a square is:
Let $(\alpha,\beta)$ be circumcenter of the triangle formed by vertices $(1,5)$, $(-3,4)$ and $(10,-31)$. Then value of $8\alpha-2\beta$ equals
Let A ∈ (0, 0), B ∈ (5, 0), C ∈ (5, 3) and D ∈ (0, 3) are the vertices of rectangle ABCD. If P is a variable point lying inside the rectangle ABCD and d(P, L) denotes perpendicular distance of point P from line L. If d(P, AB) ≤ min{d(P, BC), d(P, CD), d(P, AD)}, then area of the region in which P lies is :
The coordinate of point $P$ on the line $3x+2y+10=0$ such that $|PA-PB|$ is maximum, where $A=(4,2)$ and $B=(2,4)$, is
Area bounded by the straight lines $x^2y-y^3-x^2+5y^2-8y+4=0$ (in sq. units) is
Let $P$ be a point on the line segment joining $A(5\cos\alpha,5\sin\alpha)$ and $B(5\cos\beta,5\sin\beta)$ such that $3PA=2PB$. If $|\alpha-\beta|=\dfrac{\pi}{3}$, the locus of $P$ is
Consider three curves $H:(x+a)y=\lambda$, $\lambda<0$, $a>0$; $C: x^2+y^2-21y+109=0$; $P: y^2=bx$, $b>0$. Let the line $2x-y+8=0$ touch $H$, $C$ and $P$ at $L$, $M$, $N$ respectively such that $LM=MN=\sqrt{45}$. Then $8\lambda+b+a$ is
The point $(2,1)$ is translated parallel to $L:x-y=4$ by $2\sqrt3$ units. If new point $Q$ is in the third quadrant, equation of line through $Q$ perpendicular to $L$ is
The radical centre of circles described on the three sides $4x-7y+10=0$, $x+y=5$, and $7x+4y=15$ of a triangle as diameters is
If a circle is inscribed in ellipse $x^2+4y^2=4$, then the range of radius of the circle is
Two sides of a triangle are $3x+4y-24=0$ and $2x+y-16=0$. Circumcentre is at $(0,6)$. Find the inradius.
Given lines $\dfrac{x}{a}+\dfrac{y}{b}=1$ and $ax+by=1$ are two variable lines, $a$ and $b$ being parameters connected by $a^2+b^2=ab$. The locus of the point of intersection is
Let $P$ be a point on the line segment joining $A(5\cos\alpha,5\sin\alpha)$ and $B(5\cos\beta,5\sin\beta)$ such that $3PA=2PB$. If $|\alpha-\beta|=\dfrac{\pi}{3}$, the locus of $P$ is
Consider two circles $C_1:(x-1)^2+(y-4)^2=16$ and $C_2:(x-13)^2+(y-9)^2=81$. If a circle of radius $r$ touches the $x$-axis and both $C_1$ and $C_2$ externally, then $r$ is equal to