CBSE Class 10 Mathematics Basic 2023: question 26(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. LHS $=\frac{1}{\cos \theta }(1-\sin \theta )\left(\frac{1}{\cos \theta }+\frac{\sin \theta }{\cos \theta }\right)$

   1 mark

2. $=\frac{1}{\cos \theta }(1-\sin \theta )\cdot \frac{1+\sin \theta }{\cos \theta }$

   1 mark

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

   ½ mark

4. $=\frac{{\cos }^2\theta }{{\cos }^2\theta }=1=$ RHS [${\sin }^2\theta +{\cos }^2\theta =1$]

   ½ mark

Answer: LHS = 1 = 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