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Mathematics · 2026 · 1 mark
Three Dimensional GeometryDirection Cosines and Direction Ratios of a Line1 markUnderstandassertion reason
CBSE 2026 · Region 2 · Set 1 · Q20
Assertion (A): A line can have direction cosines < 1, 1, 1 > Reason (R): cos θ=1 is possible for θ=0.
Assertion (A) : A line can have direction cosines < $\displaystyle 1$, $\displaystyle 1$, $\displaystyle 1$ >
Reason (R) : $\displaystyle \cos \theta=1$ is possible for $\displaystyle \theta=0$.
Official answer
(D)
Assertion (A) is false, but Reason (R) is true.
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CBSE Class 12 Mathematics past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.