Differentiation with respect vector

AI Thread Summary
Differentiation and integration with respect to vectors can be formalized using the gradient operator, denoted as ∇. The relationship df/dt can be expressed as ∇f · Dvec{r}, linking the change in a scalar function to the change in a vector function. The integration of a scalar function with respect to a vector can be represented as ∫f dvec{r} = ∇^(-1)f. This discussion suggests that it is indeed possible to differentiate and integrate vector-valued functions, expanding the mathematical framework for vector calculus. Overall, the exploration of vector differentiation and integration opens up new avenues for understanding vector-valued functions.
Jhenrique
Messages
676
Reaction score
4
Helow!

For a long time I aks me if exist differentiation/integration with respect to vector and I think that today I discovered the answer! Given:
f(\vec{r}(t))
So, df/dt is:
\bigtriangledown f\cdot D\vec{r}
But, df/dt is:
\frac{df}{d\vec{r}}\cdot \frac{d\vec{r}}{dt}
This means that:
\frac{d\vec{r}}{dt}=D\vec{r}
and:
\frac{df}{d\vec{r}}=\bigtriangledown f

So, analogously, the integration with respect to vector is:
\int f\;d\vec{r}=\bigtriangledown ^{-1}f

What make I think that:
\frac{\mathrm{d} }{\mathrm{d} \vec{r}}=\bigtriangledown

Then, would be possible to formalize the differintegration of vector with respect to vector too by:
\bigtriangledown \cdot \vec{f},\;\;\;\bigtriangledown \times \vec{f},\;\;\;\bigtriangledown^{-1} \cdot \vec{f}\;\;\;and\;\;\;\bigtriangledown^{-1} \times \vec{f}

What you think about all this?
 
Mathematics news on Phys.org
It may make more sense of you expand \vec r in a basis - say: Cartesian.
See which ideas make sense.

But you can differentiate and integrate vectors - look up vector-valued functions for instance.
 
Thread 'Video on imaginary numbers and some queries'
Hi, I was watching the following video. I found some points confusing. Could you please help me to understand the gaps? Thanks, in advance! Question 1: Around 4:22, the video says the following. So for those mathematicians, negative numbers didn't exist. You could subtract, that is find the difference between two positive quantities, but you couldn't have a negative answer or negative coefficients. Mathematicians were so averse to negative numbers that there was no single quadratic...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Thread 'Unit Circle Double Angle Derivations'
Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...
Back
Top