Which of the following is false? 1. If $(a, b, c)$ are direction ratios of a line, then $a^2+b^2+c^2 \neq 1$. 2. The direction cosines of a line can be its direction ratios but not vice-versa. 3. If $(l, m, n)$ is one set of direction cosines, then $(-l,-m,-n)$ is also a valid set. 4. If…

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Which of the following is false? 1. If $(a, b, c)$ are direction ratios of a line, then $a^2+b^2+c^2 \neq 1$. 2. The direction cosines of a line can be its direction ratios but not vice-versa. 3. If $(l, m, n)$ is one set of direction cosines, then $(-l,-m,-n)$ is also a valid set. 4. If $\left(l_1, m_1, n_1\right)$ and $\left(l_2, m_2, n_2\right)$ are direction cosines of perpendicular lines, then $l_1 l_2+m_1 m_2+n_1 n_2=1$.

Aicharya · Accepted Answer

If the direction cosines of two perpendicular lines are $l_1, m_1, n_1$ and $l_2, m_2, n_2$, then $l_1 l_2+m_1 m_2+n_1 n_2=0$

Which of the following is false? 1. If \((a, b, c)\) are direction ratios of a line, then \(a^2+b^2+c^2 \neq…

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