Question

EXPLAIN THIS QUESTION PLS..........​

Answer 1

Step-by-step explanation:

${ |a + b| }^{2} = {a}^{2} + {b}^{2} + 2ab \cos( \alpha )$

where alpha is the angle required

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

$\cos( \alpha ) = - 1$

hope this will help u