Velvet Star Monitor

Standout celebrity highlights with iconic style.

news

Questions tagged [partial-derivative]

Writer Sophia Terry
Ask Question

For questions regarding partial derivatives. The partial derivative of a function of several variables is the derivative of the function with respect to one of those variables, with all others held constant.

6,320 questions
0 votes 0 answers 26 views

Show the partial derivative and continuity of the function below.

The function is defined to be $$ f(x,y) = \begin{cases} (x^2+y^2)\sin(\frac{1}{\sqrt{x^2+y^2}}) , & \text{$(x,y)\neq(0,0)$} \\ 0, & \text{$(x,y)=(0,0)$} \end{cases}. $$ Prove that the partial ... user avatar Techlover
  • 59
0 votes 1 answer 23 views

Simplifying equations of partial derivatives by substitution

Let $u=\ln x$, $v = \ln y$. Then what is another form of $$x^2 \left( \frac{\partial^2 f}{\partial x^2}\right) + y^2 \left(\frac{\partial^2 f}{\partial y^2}\right) + x \left( \frac{\partial f}{\... user avatar Jordan G
  • 139
1 vote 0 answers 59 views

${f}\begin{pmatrix}x \\y \\\end{pmatrix}$=$\begin{pmatrix}x^2-y^2 \\2xy \end{pmatrix}$ is differentiable at each point

I need help with understanding some steps of a task. I tried to solve the uncertainty by myself by using "Approach zero" but the problem is, that I am not able to write these kind of ... user avatar Analysis_Mark
  • 292
0 votes 0 answers 4 views

Deriving SDE of Forward Rate

We have $$ F(t,T,+\delta)=F(0,T,T+\delta)e^{\int_{0}^{t}\beta(u,T)dW_{u}+0.5\int_{0}^{t}\beta^{2}(u,T)du} $$ How would we derive the SDE of the above equation? Taking partial derivatives, I got: $$ \... user avatar user1066635
  • 1
0 votes 1 answer 29 views

Product notation in partial differentiation

For a function $f:\mathbb{R}^n\to \mathbb{R}$, is it correct to write, for any $n\in \mathbb{N}$, the expression $$ \frac{\partial^n f}{\partial x_1\cdots \partial x_n}=\frac{\partial^n f}{\prod_{i=1}^... user avatar sam wolfe
  • 3,418
-1 votes 0 answers 51 views

How can I prove this partial derivative question? [closed]

Let $z=y\ln(x^2-y^2)$. Prove that $\dfrac1x \dfrac{\partial z}{\partial x}+ \dfrac1y \dfrac{\partial z}{\partial y} = \dfrac{z}{y^2}$. user avatar Novyツ
  • 9
0 votes 0 answers 25 views

Swapping partial derivatives and limits

What conditions does a function have to meet for the following to be true? $$\displaystyle\lim_{x\to 0}\frac{\partial}{\partial x}f(x,y)=\frac{\partial}{\partial x}\lim_{x\to 0}f(x,y)$$ I've looked ... user avatar Henrietta
  • 1
3 votes 1 answer 29 views

What is my error in this $\nabla_{\vec{v}} f(x,y,z)$ at $\vec{a} = (-1, -1, 4)$ and $\vec{v} = (\frac{\sqrt 2}{2}, \frac{1}{2}, \frac{1}{2})$ problem

I want to find gradient of $f(x,y,z) = \sqrt{xyz}$ in the direction of $\vec{v}$ at a point $\vec{a}$. That is, $\nabla_{\vec{v}} f(x,y,z)$ at $\vec{a} = (-1, -1, 4)$ and $\vec{v} = (\frac{\sqrt 2}{2},... user avatar Anand V
  • 33
0 votes 0 answers 22 views

Is the following vector expression true?

Suppose I have the following equation involving two vectors $\vec{A}$ and $\vec{B}$ that satisfy the following relation : $$\vec{\nabla}\times\frac{d\vec{A}}{dt}=k\frac{\partial \vec{B}}{\partial t}$$ ... user avatar Nakshatra Gangopadhay
  • 415
0 votes 0 answers 11 views

What is the partial derivative of a section?

I made an attempt to understand the jet bundle after reading up on fiber bundles but I got stuck at the first definition, how is the partial derivative of a section defined? The total space contains ... user avatar Emil
  • 637
0 votes 1 answer 55 views

Derivatives are not matching textbook. Are my assumptions or calculations wrong?

I am trying to follow a derivation in a book, but I get a different result and can't figure out what I'm missing. I have a system of equations like this: \begin{align} \dot{r} &= v \\ 0 &= g(r)... user avatar Tue
  • 147
0 votes 0 answers 37 views

What is $\nabla f$ where $f: \mathbb{R} \rightarrow \mathbb{R}$ (real to real)

Let's say $f$ is a function that converts a real number to a different real number. In other words, $f: \mathbb{R} \rightarrow \mathbb{R}$. What is the gradient $\nabla f$? In this case, is $\nabla f(... user avatar Intrastellar Explorer
  • 121
2 votes 2 answers 63 views

Trying to understand a solution to a problem regarding chain rule and partial derivatives

I'm trying to understand the provided solution yet something doesnt seem right, I'll share the problem, my solution (Which is incorrect according to my lecturer), and the lecturer's solution. The ... user avatar Aishgadol
  • 163
1 vote 0 answers 44 views

How to find partial derivative function $ P_i = \frac{b_iz_i^k}{z_i^k+\theta_i^k} $

I have a function that converts a vector of real-valued variables $\vec z$ to a probability $\vec P$. In the elementwise version of this function, $i = 1, 2, ..., K$ and $b_i = \frac{z_i}{\sum_{v=1}^... user avatar Colin M. Lynch
  • 37
1 vote 0 answers 21 views

How a gradient gives direction of steepest ascent in gradient decent algorithm to find direction of minima

I have read about Directional derivatives and know that to maximize the dot product of gradient vector and u(vector) we have to make cosine 0 deg as its 1. But after we do this we are only left with ... user avatar Sid Dhawan
  • 11

15 30 50 per page12345422