   Math Question - Sin/Cos/Radians
  I was hoping someone could help me with a bit of simple maths. I am currently studying games programming but we have not yet done maths (its been a while!). I recently used the following code in a 2d game, to set movement in a direction. float radians = angle * (pi / 180);mVelocityX = sin(radians) * speed;mVelocityY = -cos(radians) * speed;Now it works, and I sort of understand the first line, the conversion between radians and degrees. What completely eludes me is why the next two lines give me the correct direction, if anyone is able to help me i'd be grateful.Thanks in advance.   
  Hopefully this will help...http://www.maths.abdn.ac.uk/~igc/tch/ma1002/diff/node51.html;  1) In your world all parameters are probably represented by X and Y coordinates.2) I gather your character's movement speed is reprisented by direction and speed.3) In order for you to move your character you will need to change it's X,Y position.PROBLEM: You're speed is in size + direction, how will you add the two?SOLUTION: Trigonometric functions can split the directional speed into it's X,Y components , so you can add these speed components to the X,Y coordinates.   