Explain the difference between vector addition and vector resolution?

Answer 1

Vector addition derives a new vector from two or more vectors. The sum of two vectors, A = (a, b) and B = (c,d), is given as S = A+B = (a+c, b+d). Vector resolution should be called something like vector decomposition. It is simply the operation of taking a vector A and writing the components of that vector, (a,b). It's very easy to determine the horizontal and vertical component vectors using trigonometric identities. The vector A starts at the origin and ends at a point (a, b), vector resolution is the method for determining a and b. The lengths a and b can be computed by knowing the length of the original vector A (the magnitude or A) and the angle from the horizontal, theta: a = A*cos(theta), b = A*sin(theta). Going in the other direction, the vector A can be reconstructed knowing only a and b. The magnitude is given by A = sqrt(a*a + b*b). The angle theta is given by solving cos(theta) = a/A (or sin(theta) = b/A). And, in fact, if you take the component vectors a and b, their sum gives the original vector, A = a + b, where a should be thought of as a*i and b = b*j where i and j are unit vectors in x and y directions.
Vector addition is when you add two or more vectors together to create a vector sum.