If the points $(1,1, \lambda)$ and $(-3,0,1)$ are equidistant from the plane $3 x+4 y-12 z+13=0$, then…

If the points $(1,1, \lambda)$ and $(-3,0,1)$ are equidistant from the plane $3 x+4 y-12 z+13=0$, then integer value of $\lambda$ is
  1. $2$
  2. $1$
  3. $3$
  4. $4$

Solution

Given $\mathrm{A}(1,1, \lambda)$ and $\mathrm{B}(-3,0,1)$ are equidistant from $3 \mathrm{x}+4 \mathrm{y}-12 \mathrm{z}+13=0$ $\begin{aligned} & \therefore\left|\frac{3(1)+4(1)-12 \lambda+13}{\sqrt{9+16+144}}\right| \\ & \therefore\left|\frac{20-12 \lambda}{13}\right|=\left|\frac{-8}{13}\right| \\ \therefore & 20-12 \lambda=\pm 8 \\ \therefore & 20-12 \lambda=8 \text { or } 20-12 \lambda=-8 \Rightarrow \lambda=1 \text { or } \lambda=\frac{7}{3} \end{aligned}$

Asked in: MHT CET 2020 (15 Oct Shift 1)

Practice more Line and Plane questions on Aicharya