Last updated at May 29, 2018 by Teachoo

Transcript

Misc 11 Prove tan-1 ((√(1 + x) − √(1 − x))/(√(1 + x) + √(1 − x))) = π/4 - 1/2 cos-1 x, - 1/√2 ≤ x ≤ 1 [Hint: put x = cos 2θ] Taking L.H.S. tan-1 ((√(1 + x) − √(1 − x))/(√(1 + x) + √(1 − x))) Put x = cos 2𝜃 = tan-1 ((√(1 + cos 2θ) − √(1 − cos 2θ))/(√(1 + cos 2θ) + √(1 − cos 2θ))) = tan-1 ((√(2 cos^2 θ) − √(2 sin^2 θ))/(√(2 cos^2 θ) + √(2 sin^2 θ))) = tan-1 ((√2 cos θ − √2 sin θ)/(√2 cos θ + √(2 ) sin θ)) = tan-1 (( √2 (cos θ − sin θ))/(√2 (cos θ + sin θ))) = tan-1 (( (cos θ − sin θ))/( (cos θ + sin θ))) Dividing by cos θ = tan-1 ((cos𝜃/cos𝜃 − sin𝜃/cos𝜃 )/(cos𝜃/cos𝜃 + sin𝜃/cos𝜃 )) = tan-1 ((1 − tan θ)/(1 + tan θ)) = tan-1 ((1 − tan θ)/(1 + 1 . tan θ)) = tan-1 ((tan〖 𝜋/4〗 − tanθ)/(1 + tan〖𝜋/4 .〖 tan〗θ 〗 )) = tan-1 (tan (𝜋/4 −θ)) = 𝜋/4 − θ We know x = cos 2𝜃 cos-1 x = 2θ 1/2 cos-1 x = θ Hence, tan-1 ((√(1 + x) − √(1 − x))/(√(1 + x) + √(1 − x))) = 𝜋/4 – θ = 𝜋/4 – 1/2 cos-1x

Chapter 2 Class 12 Inverse Trigonometric Functions

Ex 2.1, 5
Important

Ex 2.1, 8 Important

Ex 2.1, 12 Important

Ex 2.1, 14 Important

Example 5 Important

Example 8 Important

Ex 2.2, 12 Important

Ex 2.2, 15 Important

Ex 2.2, 19 Important

Ex 2.2, 21 Important

Example 10 Important

Example 12 Important

Example 13 Important

Misc. 2 Important

Misc. 7 Important

Misc. 10 Important

Misc. 11 Important You are here

Misc 12 Important

Misc. 17 Important

Class 12

Important Question for exams Class 12

- Chapter 1 Class 12 Relation and Functions
- Chapter 2 Class 12 Inverse Trigonometric Functions
- Chapter 3 Class 12 Matrices
- Chapter 4 Class 12 Determinants
- Chapter 5 Class 12 Continuity and Differentiability
- Chapter 6 Class 12 Application of Derivatives
- Chapter 7 Class 12 Integrals
- Chapter 8 Class 12 Application of Integrals
- Chapter 9 Class 12 Differential Equations
- Chapter 10 Class 12 Vector Algebra
- Chapter 11 Class 12 Three Dimensional Geometry
- Chapter 12 Class 12 Linear Programming
- Chapter 13 Class 12 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.