(6.) If the S.D between the lines $\frac{x-1}{1}=\frac{y}{-1}=D\frac{z} {2}$ and $\frac{x+1}{2}=\frac{y}{2}=\frac{z-3}{\lambda}$ be unity then $\lambda$ must be equal to $-20 \pm \sqrt{\mu}$ then the...

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Extracted text: (6.) If the S.D between the lines $\frac{x-1}{1}=\frac{y}{-1}=D\frac{z} {2}$ and $\frac{x+1}{2}=\frac{y}{2}=\frac{z-3}{\lambda}$ be unity then $\lambda$ must be equal to $-20 \pm \sqrt{\mu}$ then the integer $\mu$ must be equal to