Math Help - Vector Q - Help Needed!!

1. Vector Q - Help Needed!!

Hey... I am having a bit of difficulty with the following question, can someone help me out please?

If V1 = ai(hat) + bj(hat) and V2 = bi(hat) and aj(hat)

1) Write down unit vectors in the V1 and V2 directions

2) Show that cot(theta) = 2ab/(a^2 - b^2) (denominator modulus), where theta is the angle between the two vectors.

Sorry, it seems difficult when you have to type the maths instead of writing it out! I'd really appreciate the answers, and how you got to them, so I know for next time... thank you!

2. For any vector $v \not= 0$ the vector $\frac{v}{{\left\| v \right\|}}$ is a unit vector in the direction of v.

For the second use the law of cosines.