✓ Board-verified
Mathematics · 2026 · 1 mark
CBSE 2026 · Region 3 · Set 1 · Q20
Assertion (A): tan 2 θ is not defined at θ=45^°. Reason (R): sin 90^° ≠ cos 90^°.
Assertion (A) : $\displaystyle \tan 2 \theta$ is not defined at $\displaystyle \theta=45^{\circ}$.
Reason (R) : $\displaystyle \sin 90^{\circ} \neq \cos 90^{\circ}$.
Official answer
(B)
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
All Introduction to Trigonometry questions2026 question paperNCERT solutions: Introduction to TrigonometryPractice Introduction to Trigonometry →
More from Introduction to Trigonometry
- Prove that: (1+ cot θ-cosec θ)(1+ tan θ+ sec θ)=22026
- Evaluate: (5 cos^2 60^°+4 sec^2 30^°- tan^2 45^°)/(sin^2 30^°+ cos^2 30^°) OR Prove that: 1+(cot^2 α)/(1+cosec α)=cosec α2026
- [5/8 sec^2 60^°- tan^2 60^°+ cos^2 45^°] is equal to2023
- If sin θ+ cos θ=√3, then prove that tan θ+ cot θ=1 OR Prove that: ( sin A+ sec A)^2+( cos A+cosec A)^2=(1+ sec A cosec A)^22026
- The hour-hand of a clock is 6 cm long. The angle swept by it between 7:20 a.m. and 7:55 a.m. is:2023
- If x=a cos θ and y=b sin θ, then the value of b^2 x^2+a^2 y^2 is:2024
- Assertion: For an acute angle θ, value of cosec θ cannot be 1/(√2). Reason (R): cosec θ ≥ 1 for 0^° ≤ θ ≤ 90^°2025
- Prove that (cosec A- sin A)( sec A- cos A)=1/(cot A+ tan A).2023
CBSE Class 10 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.