Use the dot product formula: ( mathbf{a}cdotmathbf{b} = |mathbf{a}|,|mathbf{b}| costheta )
Solve for the angle: ( theta = cos^{-1}!left(dfrac{mathbf{a}cdotmathbf{b}}{|mathbf{a}|,|mathbf{b}|}right) )
Compute the dot product of the two vectors
Compute the magnitude of each vector
Substitute the values into the formula
Evaluate the inverse cosine to get the angle
Ensure the vectors are nonzero before using the formula