Mathematics · 2018
JEE Main · 15 April 2018, Shift 1 · Q85
If a, b, and c are unit vectors such that a +2 b +2 c = 0, then | a × c | is equal to:
If $\displaystyle \overrightarrow{\mathrm{a}}, \overrightarrow{\mathrm{b}}$, and $\displaystyle \overrightarrow{\mathrm{c}}$ are unit vectors such that $\displaystyle \overrightarrow{\mathrm{a}}+2 \overrightarrow{\mathrm{~b}}+2 \overrightarrow{\mathrm{c}}=\overrightarrow{0}$, then $\displaystyle |\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{c}}|$ is equal to :
Official answer
(1)
$\displaystyle \frac{\sqrt{15}}{4}$
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JEE Main 2018 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.