Angle for A + B = n times A - B Magnitude

[BeckyStar678]

Homework Statement

two vectors A and B have precisely equal magnitudes. For the magnitude of A +B to be larger than the magnitude of A-B by the factor n, what must be the angle between them?

Homework Equations

The Attempt at a Solution

i don't understand this because a-b would equal 0. so wouldn't the angle just be 0 degrees?

 

[alphysicist]

Hi BeckyStar678,

Homework Statement

two vectors A and B have precisely equal magnitudes. For the magnitude of A +B to be larger than the magnitude of A-B by the factor n, what must be the angle between them?

Homework Equations

The Attempt at a Solution

i don't understand this because a-b would equal 0. so wouldn't the angle just be 0 degrees?

The vectors $\vec A$ and $\vec B$ have the same magnitude, but $\vec A-\vec B$ does not equal zero unless they point in the same direction. You have to use the rules of vector addition to write out what $\vec A+\vec B$ and $\vec A-\vec B$ are.