2a-b

=(2cosθ-√3，2sinθ+ 1)

|2a - b|

= 2a-b membrane

=(2cosθ-√3)^2+(2sinθ+ 1)^2

=4+4-4√3cosθ+4sinθ

= 8+8 sine (θ-30 degrees)

So,

=0