Introduction to Trigonometry
CBSE 2026 Board Exam Set 2 (Code 30/1/2)
CBSE_BOARD_PYQ_2026_30_1_2
Grade 10
Question:
[Section B]
Evaluate: $\dfrac{5 \cos^2 60^\circ + 4 \sec^2 30^\circ - \tan^2 45^\circ}{\sin^2 30^\circ + \cos^2 30^\circ}$.
OR
If $\sin (A - B) = 1/2$ and $\cos (A + B) = 1/2$, find $A$ and $B$.
Step-by-Step Solution
Key Concept: Main: Standard values. OR: $A-B = 30^\circ, A+B = 60^\circ$.
[Main Question Solution]
Denominator $= 1$. Numerator $= 5(1/4) + 4(4/3) - 1 = 67/12$. [2.0 Marks]
-------------------------------
[OR Choice Question Solution]
$A - B = 30^\circ, A + B = 60^\circ \Rightarrow 2A = 90^\circ \Rightarrow A = 45^\circ, B = 15^\circ$. [2.0 Marks]
Correct Answer: Main: 67/12 | OR: A = 45°, B = 15°
Confused by the solution? Ask the AI to explain a specific step, tell you where you went wrong, or break down the key trap in this question.