Question

Find the projection of the vector A=i-2j+k on the vector B=4i-4j+7k

Answer 1

The scalar projection is $proj_BA=\frac{A*B}{|B|}=\frac{1*4+(-2)*(-4)+1*7}{\sqrt{4^2+(-4)^2+7^2}}=\frac{19}{9}.$