Aspire Faculty ID #18032 · Topic: JEE Main 2026 (23 January Evening Shift) · Just now
JEE Main 2026 (23 January Evening Shift)

If the image of the point $P(a, 2, a)$ in the line $\dfrac{x}{2} = \dfrac{y + a}{1} = \dfrac{z}{1}$ is $Q$ and the image of $Q$ in the line $\dfrac{x - 2b}{2} = \dfrac{y - a}{1} = \dfrac{z + 2b}{-5}$ is $P$, then $a + b$ is equal to ______.

Solution

Direction vector of first line: $(2,1,1)$

Using reflection property

$\dfrac{2\lambda - a + a}{2} = -5\mu - 2b$

and

$\dfrac{a + 4\lambda - a}{2} = 2\mu + 2b$

Solving

$\lambda - \mu = b$

$\lambda - \mu = 2a$

$\Rightarrow b = 2a$

Further solving

$a = 1 \Rightarrow b = 2$

$\Rightarrow a + b = 3$

Previous 10 Questions — JEE Main 2026 (23 January Evening Shift)

Nearest first
1
If the solution curve $y = f(x)$ of the differential equation $(x^2 - 4)y' - 2xy + 2x(4 - x)^2 = 0,; x > 2$, passes t…
Topic: JEE Main 2026 (23 January Evening Shift)
2
Let $\sum a_k = \alpha n^2 + \beta n$. If $a_{10} = 59$ and $a_6 = 7a_4$, then $\alpha + \beta$ is equal to:
Topic: JEE Main 2026 (23 January Evening Shift)
3
An equilateral triangle $OAB$ is inscribed in the parabola $y^2 = 4x$ with vertex at origin. Then the minimum distance …
Topic: JEE Main 2026 (23 January Evening Shift)
4
Question
Topic: JEE Main 2026 (23 January Evening Shift)
5
If $z = \dfrac{\sqrt{3}}{2} + \dfrac{i}{2},; i = \sqrt{-1}$, then $(z^{201} - i)^5$ is equal to:
Topic: JEE Main 2026 (23 January Evening Shift)
6
Let $A = {0,1,2,\ldots,9}$. Let $R$ be a relation on $A$ defined by $(x,y) \in R$ iff $|x-y|$ is a multiple of $3$. Gi…
Topic: JEE Main 2026 (23 January Evening Shift)
7
The number of ways, in which $16$ oranges can be distributed to four children such that each child gets at least one or…
Topic: JEE Main 2026 (23 January Evening Shift)
8
Let $I(x) = \int \dfrac{3dx}{(4x+6)\sqrt{4x^2 + 8x + 3}}$ and $I(0) = \dfrac{\sqrt{3}}{4} + 20$. If $I\left(\dfrac{1}{…
Topic: JEE Main 2026 (23 January Evening Shift)
9
The least value of$\cos^2\theta - 6\sin\theta\cos\theta + 3\sin^2\theta + 2$is:
Topic: JEE Main 2026 (23 January Evening Shift)
10
The area of the region enclosed between the circles$x^2 + y^2 = 4$ and $x^2 + (y-2)^2 = 4$ is:
Topic: JEE Main 2026 (23 January Evening Shift)

Next 10 Questions — JEE Main 2026 (23 January Evening Shift)

Ascending by ID
Ask Your Question or Put Your Review.

loading...