Question

If the sum of two unit vector is a unit vector, then what is the angle between them?

Answer 1

120 o
this may help u.........

Answer 2

Hey!


[ refer 2nd attachment ]

Using formula :-

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


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

$\cos( \alpha ) = \cos(120)$


$\alpha = 120$


The angle between them is 120° !!