The answer is no you cannot. Getting a car loan involves a contract. A 17 year old is still considered a minor in the eyes of the law. Because of this, a minor cannot enter into a binding contract.
The tangent at a given point on a curve is the straight line that just touches the curve at the given point. Leibniz defined this as being the straight line through two infinitesimally close points on the curve at that point, leading to the relationship between the slope of the tangent and the first derivative of the function (if both exist) at that point.
A spherical lens is the same in all directions; you can turn it around, and it doesn't change the way it magnifies, or the way it blurs: A cylindrical lens has refractive power in one direction, like a bar reading magnifier. The rotational orientation of that power is indicated in a prescription with an axis notation. The axis in a prescription describes the orientation of the axis of the cylindrical lens.