CBSE Class 10 Mathematics Standard 2025: question 9

Hints

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Step-by-step solution

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1. Write in sines and cosines: $\frac{\cos \theta }{\sin \theta }+\frac{\sin \theta }{\cos \theta }=\frac{{\cos }^2\theta +{\sin }^2\theta }{\sin \theta \cos \theta }$.

2. Since ${\sin }^2\theta +{\cos }^2\theta =1$, this equals $\frac{1}{\sin \theta \cos \theta }=\mathrm{cosec}\theta \sec \theta$. The answer is option (A).

   1 mark

Answer: $\mathrm{cosec}\theta \sec \theta$, option (A)

Revise the chapter

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