I don't know where to begin with this question. It's in the revision section in my textbook and I've had a look back through the book and I can't find anything helpful. I don't even know what OX is supposed to mean. Here it is:

Calculate, to the nearest degree, the acute angle between OX and the tangent to the curvey = {x}^{4} - {2x}^{3} + {3x}^{2} - 4x + 1at the point where

x = 2.

According to the back of the book the answer is 86 degrees, but I would like to know how to get there.