with respect to the x or y: let's say that your angle is in 2-space or a 2-d angle. If you want to measure it with respect to the x axis it means that you start on the x - axis and move counter clockwise to your angle. the same logic is used for the y as well
A question tells me to find an angle of a vector F with respect to positive x-axis.
Suppose the vector F points 17.1 degrees west of north. Then if I were to find angle of this vector with respect to positive x-axis, I add 17.1 degrees and 90 degrees and get 107.1 degrees, right?
On a question that asked to find the angle with respect to positive x-axis, I solved it as stated above, but it's wrong.
What is wrong with my method?