Discontinuity in the value of arctan(y/x)

In summary, after two simple line integrals, we can determine the function f(x,y) to be equal to the arctangent of p/q plus the arctangent of y/x, plus or minus pi/2 depending on the value of x. By taking limits, we can find the value of the discontinuity. The significance of this value is not explicitly stated, but it may be related to the fact that at y = 0, there is a jump between branches of the arctangent graph. This jump also relates to the discussion of the differential form being closed but not exact when theta = arctan(y/x).
  • #1
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Homework Statement
Let ## \omega = \frac{xdy -ydx}{x^2+y^2} ## and for ##p, q > 0## define the curve ##C_{p,q,x,y}##:
$$ (-p,-q) \rightarrow (x,-q) \rightarrow (x,y) $$
Let $$f(x,y) = \int_{C_{p,q,x,y}}\omega$$
Show that ##f(x,y)## is discontinuous at ##x=0## if ##y \geq 0## is fixed, but not if ## y < 0##. What is the significance of the value of this discontinuity?
Relevant Equations
Found the discontinuity to be ##2\pi## if ##y> 0## and ##\pi## if ##y=0##. However, I don't really know what the significance of this value is in this context.
after two simple line integrals we find that

$$ f(x,y) = \arctan{p/q} + \arctan{y/x} + \pi/2$$
if ##x > 0## and
$$f(x,y) = \arctan{p/q} + \arctan{y/x} - \pi/2$$
if ## x < 0 ##.
And then we can just take the limits to find the value of the discontinuity (as given above). But what is the significance of the value? I know it's a vague question but is there something very fundamental?

Perhaps something that's related is that earlier in the question there is discussion of how with ##\theta = \arctan(y/x)##, ##d\theta## is closed (as a differential form), but not exact.
 
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  • #2
The most obvious thing that comes to mind is that at ##y = 0## you are jumping from one branch of the ##\arctan## graph to the next.
 

Related to Discontinuity in the value of arctan(y/x)

What is "Discontinuity in the value of arctan(y/x)"?

Discontinuity in the value of arctan(y/x) refers to the sudden change or break in the value of the arctangent function when the input values of y and x approach certain points.

What causes discontinuity in the value of arctan(y/x)?

Discontinuity in the value of arctan(y/x) is caused by the presence of vertical asymptotes in the arctangent function. These points occur when the denominator, x, approaches zero, resulting in an undefined value.

Are there different types of discontinuity in the value of arctan(y/x)?

Yes, there are three types of discontinuity in the value of arctan(y/x): removable, jump, and infinite. Removable discontinuities occur when the limit of the function exists, but the value at that point is undefined. Jump discontinuities occur when the limit of the function approaches different values from the left and right sides of the point. Infinite discontinuities occur when the limit of the function approaches positive or negative infinity.

How can discontinuity in the value of arctan(y/x) be visualized?

Discontinuity in the value of arctan(y/x) can be visualized on a graph as a vertical asymptote where the function approaches infinity. It can also be observed as a sudden jump or break in the graph.

Why is understanding discontinuity in the value of arctan(y/x) important?

Understanding discontinuity in the value of arctan(y/x) is important in the fields of mathematics and physics, as it helps in understanding and predicting the behavior of functions and physical phenomena. It also allows for the identification and resolution of any potential errors or issues in mathematical calculations involving the arctangent function.

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