It may or may not exist. Whether or not the graph goes through the origin does not in any way affect whether or not it has a derivative. A function has a derivative if it has no discontinuities, cusps, sharp corners, or vertical tangents.
Yes, the derivative of an equation is the slope of a line tangent to the graph.
A derivative graph tracks the slope of a function.
I am assuming the you are talking about the graph of the derivative. The graph of the derivative of F(x) is the graph such that, for any x, the value of x on the graph of the derivative of F(x) is the slope at point x in F(x).
For example, if the slope at a certain point is 1.5, you can draw a line that goes through the specified point, with that slope. The line would represent the slope at that point. If you want to graph the slope at ALL POINTS, take the derivative of the function, and graph the derivative. The derivative shows the slope of a function at all points.
Inverse variation does not pass through the origin, however direct variation always passes through the origin.
It is a straight line through the origin.
Direct proportionality. Their graph would be a straight line through the origin, with the slope equal to the ratio.
The vertical line passing through the origin
Not always
The horizontal line passing through the origin.
The origin
A line. The derivative of a function is its slope. If the slope is a constant then the graph is a line.