Change of coordinates for functions

In summary, the conversation discusses the possibility of finding an explicit relation between old and new coordinates, t' and r', without knowing the exact dependence of a function R on these coordinates. It is questioned whether this is possible and if a Jacobian or other methods can be used. Additionally, the possibility of finding another function P as a function of t' and r' is also considered.
  • #1
tut_einstein
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I am trying to solve a problem with spacetime metrics and a change of coordinates for my research project.

I have an unspecified function R that depends on two coordinates t' and r' (which are the time and radial coordinates) and the only condition I'm imposing on R is that it be positive. Now, suppose I change to a new set of coordinates t and r and define R = r^2, is it possible to find an explicit relation between the old coordinate r' and r without knowing the exact dependence of R on t' and r'? I feel like it's not possible, but maybe there's a way using a Jacobian or something that I'm forgetting.

More importantly, if there's another function P that depends on t' and r', is it possible t o find P as a function of t' and r using the above information? Thanks!
 
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  • #2
Except in trivial situations, r will necessarily depend on both r' and [itex]\theta'[/itex], not just r.
 

FAQ: Change of coordinates for functions

What is a change of coordinates for functions?

A change of coordinates for functions is a mathematical process in which the independent and/or dependent variables of a function are transformed using a new set of coordinates. This allows for a different perspective or representation of the function.

Why is a change of coordinates useful in mathematics?

A change of coordinates can be useful in mathematics for a variety of reasons. It may simplify the form of a function, make it easier to analyze or solve, or reveal hidden relationships between variables.

What are the different types of coordinate systems used in a change of coordinates?

The most common types of coordinate systems used in a change of coordinates are Cartesian (x, y), polar (r, θ), and spherical (r, θ, φ). Other coordinate systems, such as cylindrical and elliptical, may also be used depending on the specific function.

How do you perform a change of coordinates for a function?

The process of performing a change of coordinates for a function involves substituting the original variables with the new variables and simplifying the resulting expression. It is important to keep track of any additional terms, such as conversion factors, that may arise from the new coordinate system.

What are some real world applications of a change of coordinates for functions?

A change of coordinates is commonly used in physics and engineering to describe motion, forces, and other physical phenomena. It is also used in higher level mathematics, such as calculus and differential equations, to solve problems involving multiple variables.

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