CBSE Class 10 Mathematics Basic 2025: question 29

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. LHS $=\frac{1+\frac{1}{\sin A}}{\frac{1}{\sin A}}$

   ½ mark

2. $=\frac{\sin A+1}{\sin A}\times \sin A=1+\sin A$

   1 mark

3. $=\frac{(1+\sin A)(1-\sin A)}{1-\sin A}$

   ½ mark

4. $=\frac{1-{\sin }^{2}A}{1-\sin A}=\frac{{\cos }^{2}A}{1-\sin A}$ = RHS [since ${\sin }^{2}A+{\cos }^{2}A=1$]. Hence proved.

   1 mark

Answer: LHS = 1 + sin A = cos²A/(1 − sin A) = RHS (proved)

Revise the chapter

• Chapter: Introduction to Trigonometry (notes, formulas, where marks are lost and every past question)
• Topic: Proving Simple Trigonometric Identities