of the vector by the scalar (so 5a=(5*3, 5*5)=(15, 25)). Adding or
subtracting two vectors gives a vector whoese components are the sum of
difference of the corresponding components of the two vectors.
5a-b=5(3, 5) - (2, 3) = (15, 25) - (2, 3) = (15-2, 25-3) = (13, 22)
there isn't any trick to calculate the angle - only a simple formula:
Let be the angle between the vectors and then you get the angle by:
Use this formula with your vectors:
By the way: This result shows: Two vectors are perpendicular if their dot-product equals zero.
PS: Please do us a favour and start a new thread if you have a new problem to do. Otherwise you risk that nobody will notice that you ask for some help again.