Write the force equation first, then turn it into an acceleration equation, then choose the form of acceleration that matches what you have — v dv/dx when x and v are involved, dv/dt when t is. Say which form you chose.
Radians, not degrees. Dot notation kept consistent. When the question wants y as a function of x, find x(t) and y(t) and eliminate t; that is a different job from resisted motion in one dimension.