There's nothing special about which contour lines are displayed, it's just a matter of choice. This is because you are looking at part of the graph that is very steep and a small change in x or y will have a big effect on the value of z. You might also notice that when you have many contour lines close together, if you go slightly off the line, the z value quickly deviates from the line's z value. See how the z value always stays the same. Try picking another contour line and follow it with your mouse. Because along this line, z always equals zero. So, that explains why we see a contour line along the line x = y. You should see in the sidebar that the (x,y,z) indicator displays (2,2,0). So if x = 2, and y = 2, z will equal 4 - 4 = 0. Each point also has a z value which is calculated by plugging the x and y values in to the expression shown in the box. In the demo above, every point in the graph has an x and y value. Contour lines aren't just limited to giving us info about mountains though, they can help us visualise a surface described by a mathematical function. These are known as contour lines, and every point on the line is at the same height. If you've ever looked at a map, particularly of a hilly or mountainous region, you may have noticed groups of lines like this:
0 kommentar(er)
