If I have two vectors X&Y, what does X-Y mean and how do I calculate it?

Answer 1

x and y will be described as an ordered n-tuple of numbers, one for each of the dimensions of the vector space in which you're working. In the 2-D case, a vector x would be described as {x1, y1} where the x1 nad y1 are the point of the tip of the vector. To add x to y (say vector y is {y1, y2} you form the vector sum as
{(x1 + y1), (x2 + y2)}. To find the difference, just reverse the sign of each of the y components to get
{(x1 - y1), (x2 - y2)}. This is true for vectors of -any- dimension.


Doug

Answer 2

Vectors X and Vector Y have its respective speed and direction. X-Y is the result when the two vectors combined just like when Billard ball X hits billard Y and the two balls stick together to form Billard ball X-Y. To solve the resulting speed and direction requires vector analysis and conservation of momentum using m1v1cos(angle1) + m2v2cos(angle2) = (m1+m2)v3cos(angle3)