JEE Main 2020 (Online) 9th January Morning ShiftQuestion 1
The projection of the line segment joining the points $(1,-1,3)$ and $(2,-4,11)$ on the line joining the points $(-1,2,3)$ and $(3,-2,10)$ is ________.
Vector Algebra
Answer$8$
Solution
Segment vector $=(1,-3,8)$; line direction $(4,-4,7)$ with length $\sqrt{16+16+49}=9$. Projection $=\frac{4+12+56}{9}=8$.