Thought I should try putting my next, very basic, question here first before starting a new thread about it.
I'm getting confused about the classical real-world problems like "If an airplane is cruising west with 300km/h and the wind is blowing from the northeast etc." and "If you want to row to a point straight across a river that flows with 3km/h etc.".
I get all the basic principles, apart from one thing - sometimes the i-component of the vector should be calculated with cosinus and the j-component with sinus, and sometimes the other way around. And I'm staring myself blind at pictures trying to understand when one or the other is appropriate.
A good explanation, or direction to some good thorough reading material, on this would be great!