posted by marley .
given vectors ,
Vector a= 2i + 3j, then the angle between vector a and y axis is?
cosine theta = (a*i)/|a|
|a| is the magnitude of the a vector,
which is sqrt13 = 3.6056
a*1 is the dot product of a and the i vector, which is 2.
Therefore cos theta = 2/3.6056 = 0.5547
theta = 56.3 degrees