At each point on a graph there are many straight lines passing
through that point. Most of them cut right through the graph,
but one special line just brushes the graph.
This one line is said to be tangent
to the graph at that point.
Click twice on the graph to draw a line that intersects the graph
at the chosen points. (This is called a |

One way to measure the direction of a line is to measure the angle it makes
with the horizontal. It's often more useful to use the The diagram shows the slope |

Go back to the Embryo Calculus page, or to the main Egg Math page.