CBSE Class 10 Mathematics Basic 2026: question 21(a)

Hints

Open one hint at a time and try again before the next.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

1. $\sec A=\sqrt{2}=\sec 45^{\circ }\Rightarrow A=45^{\circ }$

   ½ mark

2. $\tan B=\sqrt{3}=\tan 60^{\circ }\Rightarrow B=60^{\circ }$

   ½ mark

3. $2\sin A\cos B=2\sin 45^{\circ }\cos 60^{\circ }=2\times \frac{1}{\sqrt{2}}\times \frac{1}{2}=\frac{1}{\sqrt{2}}=\frac{\sqrt{2}}{2}$

   1 mark

Answer: $2\sin A\cos B=\frac{1}{\sqrt{2}}$ (or $\frac{\sqrt{2}}{2}$)

Revise the chapter

• Chapter: Introduction to Trigonometry (notes, formulas, where marks are lost and every past question)
• Topic: Relationships Between Trigonometric Ratios