# Product Dot Vectors

• February 21st 2008, 12:32 PM
Macleef
Product Dot Vectors
Given "a" and "b" unit vectors,

a) if the angle between them is 60 degrees, calculate (6a + b) product dot (a - 2b)

Now use $\cos (60^ \circ ) = \frac{{a \cdot b}}{{\left\| a \right\|\left\| b \right\|}} = a \cdot b$ to finish.