pos3D

Determines the coordinates p = [px py pz] in 3D space given p0, p1, and d

%% Determines the coordinates p = [px py pz] in 3D space given the
% initial position p0 and the projected final position p1 of a particle
% that has travelled D distance along that path... by Roche C. de Guzman (Dec. 16, 2017)
% Examples
% Inputs:
% p0 = [8 7 3]; % initial position
% p1 = [5 11 15]; % projected final position
% D = 13/2; % distance currently travelled
% Outputs:
% p = [6.5 9 9]; % current position
% D01 = 13; % distance between p0 and p1
% the01 = 67.3801; % angle formed from the xy-plane to p1
% psi01 = -36.8699; % angle formed from the y-axis of p0 to the xy-plane position of p1