The dot product increases when and point in the same direction, and drops to exactly when and are perpendicular.
Therefore, will be perpendicular to when
Here, we have used the formula .
(the vectors in the problem are really in column form, but i don't know how to type that so i put them in component form)
vectorP = 2i +5j
vectorQ = -i+ 2j
☆find the value of p·q
(I know the dot product is 8, that was ez) but the next part i don't get...
☆ if... s = kp - (p·q)q
find the value of the constant k such that s is perpendicular to q