slope, also known as "angular number", indicates the degree of slope of a straight line relative to the horizontal axis. The tangent value of the Angle between a straight line and the direction of the positive half axis of the horizontal axis of a plane rectangular coordinate system is that the straight line is relative to the slope of the coordinate system. The straight line and the X-axis are perpendicular to each other, and the right tangent value is infinite, so the straight line does not have a slope. When a straight line L slope exists, for a first Function y=kx+b, k is the Function imagery slope.