# Misc 19 - Chapter 10 Class 12 Vector Algebra

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.

Miscellaneous

Misc 1
Important

Misc 2

Misc 3 Important

Misc 4

Misc 5 Important

Misc 6

Misc 7 Important

Misc 8 Important

Misc 9

Misc 10 Important

Misc 11 Important

Misc 12 Important

Misc 13 Important

Misc 14 Important

Misc 15 Important

Misc 16 Important

Misc 17 Important

Misc 18 Important

Misc 19 Important You are here

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.