If sin 𝜃 + cos 𝜃 =√3, then prove that tan 𝜃 + cot 𝜃 = 1
CBSE Class 10 Sample Paper for 2020 Boards - Maths Standard
CBSE Class 10 Sample Paper for 2020 Boards - Maths Standard
Last updated at August 14, 2026 by Teachoo
Transcript
Question 32 (OR 1st question) If sin 𝜃 + cos 𝜃 =√3, then prove that tan 𝜃 + cot 𝜃 = 1 sin 𝜃 + cos 𝜃 =√3 Squaring both sides (sin 𝜃 + cos 𝜃)2 = (√3)^2 (sin 𝜃 + cos 𝜃)2 = 3 sin2 𝜃 + cos2 𝜃 + 2 cos θ sin θ = 3 Putting sin2 𝜃 + cos2 𝜃 = 1 1 + 2 cos θ sin θ = 3 2 cos θ sin θ = 3 – 1 2 cos θ sin θ = 2 cos θ sin θ = 1 We have to prove tan 𝜃 + cot 𝜃 = 1 Solving LHS tan 𝜃 + cot 𝜃 = sin𝜃/cos𝜃 +cos𝜃/sin𝜃 = (sin^2𝜃 + cos^2𝜃)/(cos𝜃 sin𝜃 ) Putting sin2 𝜃 + cos2 𝜃 = 1 = 1/(cos𝜃 sin𝜃 ) From (1): cos θ sin θ = 1 = 1/1 = 1 = RHS Since LHS = RHS Hecne proved