# Misc 19

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Misc 19 If θ is the angle between any two vectors 𝑎 and 𝑏, then 𝑎 ⋅ 𝑏 = 𝑎 × 𝑏 when θ is equal to (A) 0 (B) 𝜋4 (C) 𝜋2 (D) π Given, 𝑎 ⋅ 𝑏 = 𝑎× 𝑏 So, 𝑎 𝑏 cos θ = 𝑎 𝑏 sin θ cos θ = sin θ We know, that cos 𝜋4 = sin 𝜋4 = 1 2 ∴ θ = 𝝅𝟒 Therefore, the angle between the vectors 𝑎 and 𝑏 is 𝜋4, So, option (B) is correct.

Chapter 10 Class 12 Vector Algebra

Ex 10.2, 7
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Ex 10.2, 9 Important

Ex 10.2, 10 Important

Ex 10.2, 13 Important

Ex 10.2, 17 Important

Example 14 Important

Example 16 Important

Example 21 Important

Ex 10.3, 2 Important

Ex 10.3, 3 Important

Ex 10.3, 10 Important

Ex 10.3, 13 Important

Ex 10.3, 16 Important

Example 23 Important

Example 24 Important

Example 25 Important

Ex 10.4, 2 Important

Ex 10.4, 5 Important

Ex 10.4, 9 Important

Ex 10.4, 10 Important

Ex 10.4, 11 Important

Example 28 Important

Example 29 Important

Example 30 Important

Misc 6 Important

Misc 12 Important

Misc 13 Important

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Misc 19 Important You are here

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 9 years. He provides courses for Maths and Science at Teachoo.