So what exactly is an osculating plane? r'(t) X r (t)? Am I right?

  • Context: Graduate 
  • Thread starter Thread starter Hellken
  • Start date Start date
  • Tags Tags
    Plane
Click For Summary
SUMMARY

The osculating plane at a point on a curve defined by the vector function r(t) is determined by the cross product of the first and second derivatives, r'(t) and r''(t). This plane is characterized as being normal to the vector resulting from this cross product. To find the equation of the osculating plane, one must identify a point on the curve (x0, y0, z0) and use the normal vector derived from the cross product to formulate the plane's equation in the standard form a(x-x0) + b(y-y0) + c(z-z0) = 0. The discussion clarifies that while T(t) and N(t) are related to the tangent and normal vectors, they are not necessary for determining the osculating plane's parameters.

PREREQUISITES
  • Understanding of vector calculus, specifically derivatives of vector functions.
  • Familiarity with the concepts of tangent and normal vectors in the context of curves.
  • Knowledge of the cross product operation in three-dimensional space.
  • Ability to formulate equations of planes in three-dimensional geometry.
NEXT STEPS
  • Study the properties of the cross product in vector calculus.
  • Learn about the Frenet-Serret formulas to understand tangent and normal vectors.
  • Explore the geometric interpretation of osculating planes in differential geometry.
  • Practice deriving equations of planes from given points and normal vectors.
USEFUL FOR

Students and professionals in mathematics, physics, and engineering who are studying curves and their properties, particularly in the context of vector calculus and differential geometry.

Hellken
Messages
13
Reaction score
0
So what exactly is an osculating plane? r'(t) X r"(t)? Am I right?

From what I know it is a plane that kisses a point on the curve at point t of curve f(t) and it is a plane normal to r'(t) X r"(t)? Am I right?

So to look for this osculating plane I simply have to find the cross product of r'(t) and r"(t)?

What does it look like on a xyz graph?

====================
EDIT: By the way per definition of the equation of a plane: a(x-x0) + b(y-y0 + c(z-z0) I need to find

a) a point on the plane (x0,y0,z0)
b) a vector normal to the plane <a,b,c>

Hence if I am looking for the osculating plane I would need:

a) a point on the osculating plane (x0,y0,z0)
b) B(t) which happens to be the vector normal to my osculating plane B(t) = T(t) X N(t), from this I find my desired <a,b,c>

I put it all together and I get my osculating plane of form: a(x-x0) + b(y-y0 + c(z-z0). (Right or wrong?)
==============================
So what exactly is the cross product r'(t) X r"(t) for? Cutting down time so I don't have to go through the tedious process of finding T(t) and N(t)?
 
Last edited:
Physics news on Phys.org


You are right. Since the osculating plane passes through the curve at some point, you can take x0, y0, z0 as a point on the curve.
You don't have to find T and N (by the way, what do you mean by N?) to find a, b and c, but just r' and r''. What's so tedious on differentiating two times the curve?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 19 ·
Replies
19
Views
4K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
5K
Replies
12
Views
1K