Let A(α, 0)$A(\alpha, 0)$ and B(0, β)$B(0, \beta)$ be the points on the line 5x + 7y = 50$5x + 7y = 50$ . Let the point P$P$ divide the line segment AB$AB$ internally in the ratio 7:3$7:3$ . Let 3x - 25 = 0$3x - 25 = 0$ be a directrix of the ellipse E: (x²)/(a²) + (y²)/(b²) = 1$E: \frac{x^2}{a^2} + \frac{y^2}{b^2} = 1$ and the corresponding focus be S$S$ . If from S$S$ , the perpendicular on the x-axis passes through P$P$ , then the length of the latus rectum of E$E$ is equal to
A.(25)/(3)$\frac{25}{3}$
B.(32)/(9)$\frac{32}{9}$
C.(25)/(9)$\frac{25}{9}$
D.(32)/(5)$\frac{32}{5}$
Solution & Explanation
Related Formula
Section Formula: (x, y) = ((mx₂ + nx₁)/(m+n), (my₂ + ny₁)/(m+n))$$\text{Section Formula: } (x, y) = \left(\frac{mx_2 + nx_1}{m+n}, \frac{my_2 + ny_1}{m+n}\right)$$Directrix of Ellipse: x = (a)/(e)$$\text{Directrix of Ellipse: } x = \frac{a}{e}$$Length of Latus Rectum = (2b²)/(a)$$\text{Length of Latus Rectum } = \frac{2b^2}{a}$$
Core Logic
First, find points A and B on 5x + 7y = 50$5x + 7y = 50$.
For A on x-axis: y = 0 ⇒ 5x = 50 ⇒ α = 10 ⇒ A(10, 0)$y = 0 \Rightarrow 5x = 50 \Rightarrow \alpha = 10 \Rightarrow A(10, 0)$
For B on y-axis: x = 0 ⇒ 7y = 50 ⇒ β = (50)/(7) ⇒ B(0, (50)/(7))$x = 0 \Rightarrow 7y = 50 \Rightarrow \beta = \frac{50}{7} \Rightarrow B\left(0, \frac{50}{7}\right)$
Directrix is 3x - 25 = 0 ⇒ x = (25)/(3)$3x - 25 = 0 \Rightarrow x = \frac{25}{3}$. Thus, (a)/(e) = (25)/(3)$\frac{a}{e} = \frac{25}{3}$.
Ellipse Properties diagram for Q3 - JEE Main 2024 Evening
Focus S has coordinates (ae, 0)$(ae, 0)$. A perpendicular from S to the x-axis is simply the vertical line x = ae$x = ae$.
Since this line passes through P(3, 5)$P(3, 5)$, the x-coordinate of S must equal the x-coordinate of P.
ae = 3$ae = 3$
Now, solving for a$a$:
a = ((a)/(e)) · e = (25)/(3) · e$$a = \left(\frac{a}{e}\right) \cdot e = \frac{25}{3} \cdot e$$
Multiply the two equations: ae · (a)/(e) = 3 · (25)/(3) ⇒ a² = 25 ⇒ a = 5$ae \cdot \frac{a}{e} = 3 \cdot \frac{25}{3} \Rightarrow a^2 = 25 \Rightarrow a = 5$.
Also, ae = 3 ⇒ 5e = 3 ⇒ e = (3)/(5)$ae = 3 \Rightarrow 5e = 3 \Rightarrow e = \frac{3}{5}$.
Keywords:#Latus rectum of ellipse#JEE Main 2024 Evening Q3#Conic Sections JEE Main 2024#Ellipse Properties JEE Main 2024
More Conic Sections Previous-Year Questions — Page 6
Q3jee_main_2026_28_january_eveningParabola and Triangles
Let A$A$ be the focus of the parabolay² = 8x$y^{2} = 8x$. Let the line y = mx + c$y = mx + c$ intersect the parabola at two distinct points B$B$ and C$C$. If the centroid of the triangle ABC$ABC$ is ((7)/(3), (4)/(3))$\left(\frac{7}{3}, \frac{4}{3}\right)$, then (BC)²$(BC)^{2}$ is equal to :
Focus of y² = 8x$y^2 = 8x$ is A(2, 0)$A(2, 0)$ since 4a = 8 ⇒ a=2$4a = 8 \Rightarrow a=2$.
Let points on parabola be B(2t₁², 4t₁)$B(2t_1^2, 4t_1)$ and C(2t₂², 4t₂)$C(2t_2^2, 4t_2)$.
The centroid of Δ ABC$\Delta ABC$ is given as ((7)/(3), (4)/(3))$\left(\frac{7}{3}, \frac{4}{3}\right)$.
Equating coordinates:
Using parametric coordinates (at², 2at)$(at^2, 2at)$ systematically reduces algebraic complexity when determining intersections or triangle properties on a parabola.
Chapter Mix
Class 11 Maths: Conic Sections
Q9jee_main_2026_28_january_eveningEllipse Parameters and Latus Rectum
An ellipse has its center at (1,-2)$(1,-2)$, one focus at (3,-2)$(3,-2)$ and one vertex at (5, - 2)$(5, - 2)$. Then the length of its latus rectum is :
From the given coordinates on the major axis (y = -2$y = -2$):
Center C(1, -2)$C(1, -2)$, Focus F₁(3, -2)$F_1(3, -2)$, Vertex A₁(5, -2)$A_1(5, -2)$.
Distance from center to vertex, CA₁ = a = 5 - 1 = 4$CA_1 = a = 5 - 1 = 4$.
Distance from center to focus, CF₁ = ae = 3 - 1 = 2$CF_1 = ae = 3 - 1 = 2$.
Ellipse dimensions mapped to coordinates
Execution
Calculate eccentricity e$e$:
ae = 2 ⇒ 4e = 2 ⇒ e = (1)/(2)$$ae = 2 \Rightarrow 4e = 2 \Rightarrow e = \frac{1}{2}$$
Aligning focus, center, and vertex along a constant y-axis implies a standard shifted ellipse where absolute differences in x-coordinates yield standard parameters (a$a$ and ae$ae$) directly.
Chapter Mix
Class 11 Maths: Conic Sections
Q10jee_main_2026_28_january_eveningConfocal Ellipse and Hyperbola
Let the ellipse E: x²144 + y²169 = 1$E: \frac{x^{2}}{144} + \frac{y^{2}}{169} = 1$ and the hyperbola H: x²16 - y²λ² = -1$H: \frac{x^{2}}{16} - \frac{y^{2}}{\lambda^{2}} = -1$have the same foci. If e$e$ and L$L$ respectively denote the eccentricity and the length of the latus rectum of H$H$, then the value of 24(e + L)$24(e + L)$ is:
Eccentricity of hyperbola, e = (5)/(3)$e = \frac{5}{3}$.
Length of latus rectum of hyperbola, L = (2(16))/(λ) = (32)/(3)$L = \frac{2(16)}{\lambda} = \frac{32}{3}$.
Confocal conics usually align along the same major axis. Notice the -1$-1$ on the RHS of the hyperbola equation indicates a conjugate hyperbola orienting it vertically to match the b>a$b>a$ ellipse.
Chapter Mix
Class 11 Maths: Conic Sections
Q12jee_main_2026_28_january_eveningParametric Form and Chord Intersections
Let the circle x² + y² = 4$x^{2} + y^{2} = 4$ intersect x-axis at the points A(a, 0), a > 0$A(a, 0), a > 0$ and B(b, 0)$B(b, 0)$. Let P(2 α, 2 α), 0 < α < (π)/(2)$P(2 \cos\alpha, 2 \sin\alpha), 0 < \alpha < \frac{\pi}{2}$ and Q(2 β, 2 β)$Q(2 \cos\beta, 2 \sin\beta)$ be two points such that (α - β) = (π)/(2)$(\alpha - \beta) = \frac{\pi}{2}$. Then the point of intersection of AQ$AQ$ and BP$BP$ lies on:
Intersection of circle with x-axis provides A(2,0)$A(2,0)$ and B(-2,0)$B(-2,0)$.
Let the point of intersection of AQ$AQ$ and BP$BP$ be R(h, k)$R(h, k)$.
Since R$R$ lies on BP$BP$, the slope mBR = mBP$m_{BR} = m_{BP}$:
Locus of R$R$ is x² + y² - 4y - 4 = 0$x^2 + y^2 - 4y - 4 = 0$.
Pattern Recognition
Connecting chords from extreme diameter vertices to points whose parametric angles differ by π/2$\pi/2$ reliably generates perpendicular-like slope products or standard tangent angle identities, mapping directly to a circular locus.
Chapter Mix
Class 11 Maths: Circles
Q55jee_main_2025_02_april_eveningEllipse
If the length of the minor axis of an ellipse is equal to one fourth of the distance between the foci, then the eccentricity of the ellipse is :
A.4√(17)$\frac{4}{\sqrt{17}}$
B.√(3)16$\frac{\sqrt{3}}{16}$
C.3√(19)$\frac{3}{\sqrt{19}}$
D.√(5)7$\frac{\sqrt{5}}{7}$
Solution
Related Formula
Length of minor axis = 2b$$\text{Length of minor axis} = 2b$$Distance between foci = 2ae$$\text{Distance between foci} = 2ae$$Eccentricity: e = √(1 - (b²)/(a²))$$\text{Eccentricity: } e = \sqrt{1 - \frac{b^2}{a^2}}$$
Core Logic
We set up an algebraic equation relating b$b$, a$a$, and e$e$ from the given geometric condition, then substitute it into the eccentricity identity.
Step 1: Set up the geometric relation
Given that 2b = (1)/(4) (2ae)$2b = \frac{1}{4} (2ae)$:
Standard Ellipse relations: For standard ellipses, the ratio of axes and the eccentricity are coupled quadratic equations. Expressing b/a$b/a$ as a function of e$e$ allows direct solving of the eccentricity.
Chapter Mix
Class 11 Mathematics: Conic Sections
More Conic Sections Questions — jee_main_2024_30_january_evening
Practice past-year questions one chapter at a time. Pick an exam → subject → chapter and get every PYQ for that topic — pulled together from all past papers — with the chapter's key formulas alongside.