Question

For any two vector,if axb=a.B,what's the magnitude of c=a+b

Answer 1

Answer:

|a × b| = a.b

= > ab sinФ = ab cosФ

= > sinФ/cosФ = 1

= > tanФ = 1

= > Ф = 45

c = |a + b|

= > √(a² + b² + 2 ab cos 45)

= > √a² + b² + 2 ab/√2 )

= > √(a² + b² + √2ab)