Question

If |A| = 4 | B| = 6 | A- B | = 5 then the angle between A and B is ?​

Answer 1

Answer:

Originally Answered: If |A×B|=|A.B| then the angle between A and B will be? 45° or π/4 radians. Hence the angle between the vectors is 45° or π/4 radians!

Answer 2

If we consider θ to be the angle between the vectors A and B,

by defination of cross product and dot product,

AxB= |A||B|sinθ n

A.B = |A||B|cosθ

AxB is a vector and A.B is a scalar, which can't be equal. The question should have been with

| AxB | = A.B

Considering the correction,

| AxB | = A.B can be only possible when sinθ = cosθ ,

which is so for θ=π/4 radians.

Therfore, the angle between A and B is π/4 radians.

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