Answer:
D.90°
Explanation:
First remember that the magnitude of a vector , lets say T is the square of the dot product with itself.
This is to say
|T|=√(T×T)
Assume A≠0 and B≠0 then
Square both sides of the below equation
|A+B|²=|A-B|²
(A+B)²=(A-B)²
A(A+B)+B(A+B)=A(A-B)-B(A-B)
A²+AB+AB+B²=A²-AB-AB+B²
A²+2AB+B²=A²-2AB+B²
You notice that it simplifies to
2AB= -2AB
This means that A×B =0
Hence the angle between the vectors should be 90°
