Question

plz tell how d is the answer​

Answer 1

The question shows thatmagnitude of vectorA=magnitude of VectorB

solution:

magnitude of VectorA+B=(A^2+B^2+2ABcos∅)

we know

A^2 and B^2 both represents magnitude

so,

if ,A=B,,in magnitude then

A^2=B^2

now,

putting these value ,we get

|A+B|=(2A^2+2A^2cos∅)^1/2

similarly

|A-B|=(A^2+B^2-2ABcos∅)^1/2

=(2A^2-2A^2cos∅)^1/2

also,

|A+B|=0,,because

both the vectors are eqaul in magnitude but opposite in direction

so,

2A^2+2A^2cos∅=0

cos∅=-1

∅=180

Hence angle.between them will be 180