Changing h and j, Part One


I will consider first the case when h = j. And then three cases, h positive, h = 0, and h negative.

h Positive

Consider the function defined by

The following graph was taken from -2 < h < -1:

The next one was taken from -8.5 < h < -8.0:

Now, for values of h near to and bigger than 9, the lft side of the graph goes to the left very fast (notice the change of scale):

Note that the right 'arm' of the graph is 'continous'.
For -1< h < 0, I got the following graph

In this family of graphs, for h negative, there are going to be points of discontinuity given by those values of t that makes x and y to be undefined (because the denomiator becomes 0, at in each expression). Now, for h = -1, we get a vertical line, because in that case, x = -1 always:

Observe also, that for these values of h, while the vertex of the right arm of the graphs goes towards 0, the vertex of the other one is going far to the left, and very fast:

What happens when h = 0?

The left 'arm' has disappeared, and the right arm has a hole, and the hole is not at zero. What value of x is it? Checking at , we get . A better zoom shows that this is the case.

So for negative values of h, we get intervals where the function is undefined.

h Positive


Now let's consider what happens for h positive. Let's consider first 0 < h < 1. The next graph shows what happens for values of h that are near to 1

Observe that we got again our inverted c. For values of h near to 0, we get:

So we are getting a kind of ellipse, with a hole.
For h > 1 we got:

The greater h, the smallest the graph (Notice the change of scale!). It has a kind of parabolic shape; for increasing values of h the 'vertex' seems to approach to 0. The points where the graph 'ends' vary depending on h, getting also closer to 0. Will this approach indefinitely to 0? The next graph shows what happens for h > 10000:

The similar conclusion is obtained directly from the expressions that define x and y; since h is in the denominator of both fractions, a large value of h will make x and y be closer to 0.


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