Question

15.)if |A^+B^|=|A^|=|B^|, then angle between A and B will be
a.0°
b.120°
c.45°
d.60°​

Answer 1

Answer:-

Given:-

|A + B| = |A| = |B| =x.

$[\alpha]$ is the angle between two vectors.

Explanation:-

Applying vector formula.

$|A + B| = \sqrt{ {A}^{2} + { B}^{2} + 2ab \cos( \alpha ) } \:$

$x = \sqrt{ {x}^{2} + {x}^{2} + 2 {x}^{2} \cos( \alpha ) }$

${x}^{2} = 2 {x}^{2} + 2 {x}^{2} \cos( \alpha )$

$- {x}^{2} = 2 {x}^{2} \cos( \alpha )$

$\cos( \alpha ) = \frac{ - 1}{2}$

$\alpha = 120 \: degrees$

$\boxed{\boxed{\alpha = 120 \: degrees}}$

So, the angle between two vectors is 120 degrees.

$\boxed{\boxed{Option - B(120 degrees)}}$