CBSE Class 10 Sample Paper for 2019 Boards

CBSE Class 10 Sample Paper for 2018 Boards →
Class 10
Solutions of Sample Papers for Class 10 Boards

Question 17 (Or 1st) - CBSE Class 10 Sample Paper for 2019 Boards - Solutions of Sample Papers for Class 10 Boards

Last updated at July 31, 2026 by

Question 17 (OR 1 st question)

Prove that cot ⁡θ - tan ⁡θ = (2 cos 2 ⁡θ  - 1) / (sin⁡ θ cos ⁡θ)

Prove that cot ⁡θ - tan ⁡θ = (2 cos^2 ⁡θ - 1) / (sin⁡ θ cos ⁡θ)

Question 17 (Or 1st) - CBSE Class 10 Sample Paper for 2019 Boards - Part 2

Remove Ads

Transcript

Question 17 (OR 1st question) Prove that cot⁡𝜃−tan⁡𝜃 = (2 cos^2⁡𝜃 − 1)/(sin⁡𝜃 cos⁡𝜃 ) Solving LHS cot⁡𝜃−tan⁡𝜃 = cos⁡𝜃/sin⁡𝜃 −sin⁡𝜃/cos⁡𝜃 = (cos⁡𝜃 × cos⁡𝜃 − sin⁡𝜃 × sin⁡𝜃)/(sin⁡𝜃 cos⁡𝜃 ) = (cos^2⁡𝜃 − sin^2⁡𝜃)/(sin⁡𝜃 cos⁡𝜃 ) Now, sin2 θ + cos2 θ = 1 sin2 θ = 1 – cos2 θ = (cos^2⁡𝜃 − (1 − cos^2⁡𝜃))/(sin⁡𝜃 cos⁡𝜃 ) = (cos^2⁡𝜃 − 1 + cos^2⁡𝜃)/(sin⁡𝜃 cos⁡𝜃 ) = (2 cos^2⁡𝜃 − 1)/(sin⁡𝜃 cos⁡𝜃 ) = RHS Since LHS = RHS Hence proved

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.

Many students prefer Teachoo Black for a smooth, ad-free learning experience.