Coordinate Geometry Questions (181)

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
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
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
If the pair of perpendicular lines $4x^2 + by^2 + 2\cos\theta\cdot xy + 12x + 2\sin^2\theta\cdot y + c = 0$, $\theta \in \left(\frac{3\pi}{2}, 2\pi\right)$ intersect on the $x$-axis, then the area of the triangle formed by the given pair of lines and $y = 2$ is
Variable pairs of chords at right angles are drawn through a point $P$ (with eccentric angle $\dfrac{x}{4}$) on the ellipse $\dfrac{x^2}{4} + y^2 = 1$ to meet the ellipse at two points, say $A$ and $B$. If the line joining $A$ and $B$ passes through a fixed point $Q = (a, b)$ and the line value of $a^2 + b^2$ can be expressed as $\dfrac{m}{n}$, where $m$ and $n$ are co-prime positive integers, submit your answer as $n - m$.
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
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
Consider three curves $H:(x+a)y=\lambda$, $\lambda0$; $C: x^2+y^2-21y+109=0$; $P: y^2=bx$, $b>0$. 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
Area bounded by the straight lines $x^2y-y^3-x^2+5y^2-8y+4=0$ (in sq. units) is
A normal with slope $\frac{1}{m}$ is drawn from $P(0,-k)$ to $x^2=-12y$. The line through $Q\!\left(0,-\frac{k}{506}\right)$ parallel to the tangent at vertex meets the parabola at $R,S$. Area of $\triangle ORS = 144$ sq. units. Then $m^2$ equals
Find the largest value of $y/x$ for a point $(x,y)$ on the circle $(x-3)^2+(y-3)^2=6$.
Area bounded by the set of points $S=\{(x,y):\,||x|-1|+||y|-1|\leq1\}$ is
Chord of contact of tangents from $P,Q$ on $\dfrac{x^2}{9}+\dfrac{y^2}{16}=1$ to $\dfrac{x^2}{3}+\dfrac{y^2}{4}=1$ is normal to $2x^2+2y^2-4x-4y+1=0$. Sum of eccentric angles of $P$ and $Q$ is
A line $y = m(x-4)$ meets the $x$-axis at $P$ and the parabola $x^2 = 32y$ at $Q(x_1,y_1)$. The tangent to the parabola at $Q$ meets the $x$-axis at $R(x_2,0)$, $0 < x_2 < 6$. If the area of $\triangle PQR$ assumes a local maximum, then the value of $m$ 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
Let an ellipse have foci $S_1$ and $S_2$ with eccentricity $e = \frac{1}{2}$. For a point $P$ on the ellipse, let $\angle PS_1S_2 = \alpha$, $\angle PS_2S_1 = \beta$, $\angle S_1PS_2 = \gamma$. If $\cot\frac{\alpha}{2}$, $\cot\frac{\gamma}{2}$, $\cot\frac{\beta}{2}$ are in A.P., then $\cos(\alpha - \beta)$ 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
Two circles $x^2+y^2+14x-6y+40=0$ and $x^2+y^2-2x+6y+7=0$ have centres $C_1$, $C_2$. Another circle with centre $C_3$ on line $3x+4y-16=0$ touches $C_1$ externally and minimises $C_1C_2+C_2C_3+C_3C_1$. Its equation $x^2+y^2+ax+by+c=0$ gives $a+b+c=$
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
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
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 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
A normal with slope $\frac{1}{m}$ is drawn from $P(0,-k)$ to $x^2=-12y$. The line through $Q\!\left(0,-\frac{k}{506}\right)$ parallel to the tangent at vertex meets the parabola at $R,S$. Area of $\triangle ORS = 144$ sq. units. Then $m^2$ equals
Circle $C$ touches $x=2y$ at $(2,1)$ and intersects $C_1:x^2+y^2+2y-5=0$ at two points $P,Q$ such that $PQ$ is a diameter of $C_1$. Length of diameter of $C$ is
Find the largest value of $y/x$ for a point $(x,y)$ on the circle $(x-3)^2+(y-3)^2=6$.
Area bounded by the set of points $S=\{(x,y):\,||x|-1|+||y|-1|\leq1\}$ is
Let $S=\{(x,y)\in\mathbb{R}\times\mathbb{R}: y^2\leq8x,\;y^2\geq32-8x,\;x+y-6\geq0,\;4x-3y-8\leq0,\;x\geq0,\;y\geq0\}$. If area $=A$, value of $21A+792$ is
Chord of contact of tangents from $P,Q$ on $\dfrac{x^2}{9}+\dfrac{y^2}{16}=1$ to $\dfrac{x^2}{3}+\dfrac{y^2}{4}=1$ is normal to $2x^2+2y^2-4x-4y+1=0$. Sum of eccentric angles of $P$ and $Q$ is
A line $y = m(x-4)$ meets the $x$-axis at $P$ and the parabola $x^2 = 32y$ at $Q(x_1,y_1)$. The tangent to the parabola at $Q$ meets the $x$-axis at $R(x_2,0)$, $0 < x_2 < 6$. If the area of $\triangle PQR$ assumes a local maximum, then the value of $m$ 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
Let an ellipse have foci $S_1$ and $S_2$ with eccentricity $e = \frac{1}{2}$. For a point $P$ on the ellipse, let $\angle PS_1S_2 = \alpha$, $\angle PS_2S_1 = \beta$, $\angle S_1PS_2 = \gamma$. If $\cot\frac{\alpha}{2}$, $\cot\frac{\gamma}{2}$, $\cot\frac{\beta}{2}$ are in A.P., then $\cos(\alpha - \beta)$ is
Number of correct statements is $k$. Then $2k$ is: I) Chord joining $P(at_1^2,2at_1)$ and $Q(at_2^2,2at_2)$ on $y^2=4ax$ passes through focus when $t_1t_2=-1$ and focal chord PQ $=|a|(t_1+1/t_1)^2\ge 4a$. II) $P=\{\theta:\sin\theta-\cos\theta=\sqrt{2}\cos\theta\}$ and $Q=\{\theta:\sin\theta+\cos\theta=\sqrt{2}\sin\theta\}$, then $P=Q$. III) If $a,b,c,d$ distinct nonzero reals: $(a^2+b^2+c^2)p^2-2(ab+bc+cd)p+(b^2+c^2+d^2)\le 0$, then $a,b,c,d$ are in GP.
Let $S=\{(x,y)\in\mathbb{R}\times\mathbb{R}: y^2\leq8x,\;y^2\geq32-8x,\;x+y-6\geq0,\;4x-3y-8\leq0,\;x\geq0,\;y\geq0\}$. If area $=A$, value of $21A+792$ is
Let $P(a_1,b_1)$ and $Q(a_2,b_2)$ be two distinct points on a circle with center $C(\sqrt{2},\sqrt{3})$. Let $O$ be origin and $OC$ be perpendicular to both $CP$ and $CQ$. If the area of $\triangle OCP$ is $\sqrt{35}$, then $a_1^2+a_2^2+b_1^2+b_2^2$ is equal to
An ellipse $E:\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ ($a<b$) passes through vertices of hyperbola $H:\frac{x^2}{49}-\frac{y^2}{64}=-1$. Major and minor axes of $E$ coincide with transverse and conjugate axes of $H$. Product of eccentricities is $\frac{1}{2}$. If $l$ is the latus rectum length of $E$, then $113l=$
Let $P\left(\frac{2\sqrt{3}}{\sqrt{7}},\frac{6}{\sqrt{7}}\right)$, $Q$, $R$ and $S$ be four points on ellipse $9x^2+4y^2=36$. Let $PQ$ and $RS$ be mutually perpendicular chords and pass through the centre of ellipse. Then $\left[\frac{50}{PQ^2}+\frac{50}{RS^2}\right]=$
A normal with slope $\frac{1}{m}$ is drawn from $P(0,-k)$ to $x^2=-12y$. The line through $Q\!\left(0,-\frac{k}{506}\right)$ parallel to the tangent at vertex meets the parabola at $R,S$. Area of $\triangle ORS = 144$ sq. units. Then $m^2$ equals
In $\triangle ABC$, $X$ and $Y$ are the feet of perpendiculars drawn from $A$ to the internal angle bisectors of $B$ and $C$. The slopes of lines making $45°$ with line $XY$ are (Given slope of $BC = 2$)
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
Three distinct chords of $x^2+4y^2=2000$ from $P(0,a)$ are bisected by $x^2=20y$. Exhaustive set of $a$ is $(k_1,k_2)$. Number of positive integral solutions of $x+y=k_2-k_1$ 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
Two sides of a triangle are $3x+4y-24=0$ and $2x+y-16=0$. Circumcentre is at $(0,6)$. Find the inradius.
Equation of tangent to parabola $y^2=8x$ which is also tangent to $xy=-1$ is
The point $P(3,3)$ is reflected across the line $y=-x$. Then it is translated horizontally 3 units to the left and vertically 3 units up. Finally, it is reflected across $y=x$. What are the coordinates of the point after these transformations?
A ray of light along $x+\sqrt{3}y=\sqrt{3}$ gets reflected upon reaching $x$-axis. The equation of the reflected ray is
A variable chord of the hyperbola $\dfrac{x^2}{4}-\dfrac{y^2}{8}=1$ subtends a right angle at the centre. If this chord touches a fixed circle which is concentric with the hyperbola and $r$ is radius of the circle, then $r^2$ is
Chord of contact of tangents from $P,Q$ on $\dfrac{x^2}{9}+\dfrac{y^2}{16}=1$ to $\dfrac{x^2}{3}+\dfrac{y^2}{4}=1$ is normal to $2x^2+2y^2-4x-4y+1=0$. Sum of eccentric angles of $P$ and $Q$ 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
The number of normals drawn from the point $(8,0)$ to the parabola $x^2=4y$ is
The maximum value of $\left|\sqrt{(x^2-2)^2+(x-3)^2} - \sqrt{(x^2+2)^2+x^2}\right|$ is