Mathematics · 2019
JEE Main · 9 April 2019, Shift 2 · Q85
If a unit vector a makes angles π / 3 with i, π / 4 with j and θ ∈(0, π) with k, then a value of θ is:
If a unit vector $\displaystyle \vec{a}$ makes angles $\displaystyle \pi / 3$ with
$$\hat{i}, \pi / 4 \text { with } \hat{j} \text { and } \theta \in(0, \pi) \text { with } \hat{k} \text {, then a }
$$
value of $\displaystyle \theta$ is :
Official answer
(2)
$\displaystyle \frac{2 \pi}{3}$
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JEE Main 2019 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.