Get Answers to all your Questions

header-bg qa

Explain Solution R.D.Sharma Class 12 Chapter 27 Straight Line in Space Exercise 27.2 Question 23 Maths Textbook Solution.

Answers (1)

Answer: the value \lambda will be 1

Given: find the value of \lambda so that the following lines are perpendicular to each other;

\begin{aligned} &\frac{x-5}{5 \lambda+2}=\frac{2-y}{5}=\frac{1-z}{-1}, \frac{x}{1}=\frac{2 y+1}{4 \lambda}=\frac{1-z}{-3} \\ \end{aligned}

Hint: \begin{aligned} &\cos \theta=0 \\ \end{aligned}  because lines are perpendicular.

Solution: \begin{aligned} &\frac{x-5}{5 \lambda+2}=\frac{y-2}{-5}=\frac{z-1}{1} \\ \end{aligned}

Therefore \begin{aligned} &\cos \theta=0 \\ \end{aligned}

                         \begin{aligned} &\quad=(5 \lambda+2)(1)+(-5)(2 \lambda)+(3)(1)=0 \\ \end{aligned}

                          \begin{aligned} &=5 \lambda+2-10 \lambda+3=0 \\ &=5 \lambda=5 \\ &=\lambda=1 \end{aligned}

so the answer will be ‘1

Posted by

infoexpert21

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads