Question

The plane $XOZ$ divides the join of $(1,-1,5)$ and $(2,3,4)$ in the ratio $\lambda :1$, then $\lambda$ is -

• A. $-3$
• B. $-1/3$
• C. $3$
• D. $1/3$

Answer 1

The correct option is D $1/3$

The plane XOZ divides the join of $(1,-1,5)$ and $(2,3,4)$ in the ratio $\lambda :1$

$i.e.,y=0$ divide the join of $(1,-1,5)$ and $(2,3,4)$ in the ratio $\lambda :1.$

$\therefore \frac{3\lambda -1}{\lambda +1}=0\Rightarrow \lambda =\frac{1}{3}$.