CBSE Class 10 Mathematics Basic 2023: question 26(b)

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 $=\frac{1+\frac{1}{\cos \theta }}{\frac{1}{\cos \theta }}=\frac{\cos \theta +1}{\cos \theta }\times \cos \theta =1+\cos \theta$

   1 mark

2. Multiply and divide by $(1-\cos \theta )$: $=\frac{(1+\cos \theta )(1-\cos \theta )}{1-\cos \theta }$

   1 mark

3. $=\frac{1-{\cos }^2\theta }{1-\cos \theta }=\frac{{\sin }^2\theta }{1-\cos \theta }=$ RHS

   1 mark

Answer: LHS = RHS, hence proved

Revise the chapter

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