Let A(a, b, c) and A'(a′,b′,c′) be two distinct points in R3. Let f from [0 , 1] to R3 be defined by f(t) = (1 -t) A + t A'. Instead of calling the component functions of f ,(f1, f2, f3) let us simply write f = (x, y, z). Express x; y; z in terms of the coordinates of A and A, and t. I thought that a is the partial derivative of f1 with respect to x, b is the partial derivative of f2 with respect to y, and c is the partial derivative of f3 with respect to z. I am right? Any hint how to find the relation and to find the derivative of f?