 Hello and welcome to the session, I am Deepika here. Let's discuss a question which says write down a unit vector in x y plane making an angle of 30 degree with the positive direction of x axis. Let's start the solution. Since the vector lies in x y plane therefore that coordinate is 0, let vector a is equal to a1i plus a2j be a unit vector in x y plane. According to the question this vector is making an angle of 30 degree with the positive direction of x axis that is a1 is equal to cos 30 degree which is equal to root 3 over 2 therefore a2 is equal to cos 60 degree and this is equal to 1 over 2 therefore the unit vector a is equal to root 3 over 2i plus 1 over 2j hence the answer for this question is root 3 over 2i plus 1 over 2j. I hope the solution is clear to you. Bye and have a nice day.