JEE MAIN - Mathematics (2024 - 5th April Morning Shift - No. 4)

If the line $$\frac{2-x}{3}=\frac{3 y-2}{4 \lambda+1}=4-z$$ makes a right angle with the line $$\frac{x+3}{3 \mu}=\frac{1-2 y}{6}=\frac{5-z}{7}$$, then $$4 \lambda+9 \mu$$ is equal to :
4
13
5
6

Explanation

$$\begin{aligned} & L_1: \frac{x-2}{(-3)}=\frac{y-\frac{2}{3}}{\left(\frac{4 \lambda+1}{3}\right)}=\frac{}{(-1)} \\ & L_2: \frac{x+3}{3 \mu}=\frac{y-\frac{1}{2}}{-3}=\frac{z-5}{-7} \\ & \because L_1 \perp L_2 \\ & \Rightarrow(-3)(3 \mu)+\left(\frac{4 \lambda+1}{3}\right)(-3)+(-1)(-7)=0 \\ & -9 \mu-4 \lambda-1+7=0 \\ & \Rightarrow 4 \lambda+9 \mu=6 \\ & \end{aligned}$$

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