MHT CET20192 May 2019Morning ShiftPhysicsMathematics in PhysicsActual
If A 2 + B 2 represents the magnitude of resultant of two vectors A → + B → and A → - B → , then the angle between two vectors is
Options
- Acos - 1 - 2 A 2 - B 2 A 2 + B 2
- Bcos - 1 - A 2 - B 2 A 2 B 2
- Ccos - 1 - A 2 + B 2 2 A 2 - B 2
- Dcos - 1 - A 2 - B 2 A 2 + B 2
Correct answer
C. cos - 1 - A 2 + B 2 2 A 2 - B 2
Step-by-step solution
A 2 + B 2 = A + B 2 + A - B 2 + 2 A + B A - B . c o s θ ⇒ A 2 + B 2 = 2 A 2 + B 2 + 2 A 2 - B 2 . c o s θ ⇒ c o s θ = - A 2 + B 2 2 A 2 - B 2 ⇒ θ = c o s - 1 - A 2 + B 2 2 A 2 - B 2