Implicit Definition and 537 Threads

Hi, I'm not sure if I've solved the problem correctly In order for the Implicit function theorem to be applied, the following two properties must hold ##F(x_0,z_0)=0## and ##\frac{\partial F(x_0,z_0)}{\partial z} \neq 0##. ##(x_0,z_0)=(1,2)## is a zero and ##\frac{\partial...

Hi, I'm not sure if I've understood the task here correctly For the Implicit function theorem, ##F(x,y)=0## must hold for all ##(x,y)## for which ##f(x,y)=f(x_0,y_0)## it follows that ##f(x,y)-f(x_0,y_0)=0## so I can apply the Implicit function theorem for these ##(x,y)##. Then I can write...

This is a text book example- i noted that we may have a different way of doing it hence my post. Alternative approach (using implicit differentiation); ##\dfrac{x}{y}=t## on substituting on ##y=t^2## we get, ##y^3-x^2=0## ##3y^2\dfrac{dy}{dx}-2x=0## ##\dfrac{dy}{dx}=\dfrac{2x}{3y^2}##...

The implicit curve in question is ##y=\operatorname{arccoth}\left(\sec\left(x\right)+xy\right)##; a portion of the equations graph can be seen below: In particular, I'm interested in the area bound by the curve, the ##x##-axis and the ##y##-axis. As such, we can restrict the domain to ##[0...

My take; ##6x^2+6y+6x\dfrac{dy}{dx}-6y\dfrac{dy}{dx}=0## ##\dfrac{dy}{dx}=\dfrac{-6x^2-6y}{6x-6y}## ##\dfrac{dy}{dx}=\dfrac{-x^2-y}{x-y}## Now considering the line ##y=x##, for the curve to be parallel to this line then it means that their gradients are the same at the point##(1,1)##...

The question and ms guide is pretty much clear to me. I am attempting to use a non-implicit approach. ##\tan y=x, ⇒y=\tan^{-1} x## We know that ##1+ \tan^2 x= \sec^2 x## ##\dfrac{dx}{dy}=sec^2 y## ##\dfrac{dx}{dy}=1+\tan^2 y## ##\dfrac{dy}{dx}=\dfrac{1}{1+x^2}##...

Hi PF A personal translation of a quote from Spanish "Calculus", by Robert A. Adams: It's about advice on Lebniz's notation1=(sec2⁡y)dydx means dxdx=(sec2⁡y)dydx, I'm quite sure. Why (sec2⁡y)dydx=(1+tan2⁡y)dydx? But I'm also quite sure that the right notation for (sec2⁡y)dydx=(1+tan2⁡y)dydx...

Hi, PF ##y^2=x## is not a function, but it is possible to obtain the slope at any point ##(x,y)## of the equation without previously clearing ##y^2##. It's enough to differentiate respect to ##x## the two members, treat ##y## like a ##x## differentiable function and make use of the Chain Rule...

WARNING: Topic is very pedantic. I have used a set of different physics books over the years, and they have all had a focus on the topic of significant figures, error margins and measurement. I have never quite understood these concepts fully and the relationships between them. One aspect I...

I am confused about implicit differenciation in a few ways. The main confusion is why, in the equation ## x^2 + y^2 = 1 ##, when we are taking the derivative of the left side, ## 2x + 2yy\prime ##, are we adding a ## y\prime ## to the 2y but we aren't adding an ## x\prime ## to the 2x? I also...

$\tiny{s8.2.6.2}$ Find y' of $2x^2+x+xy=1 $\begin{array}{lll} \textit{separate variables} &xy=2x^2+x+1 \implies y=\dfrac{2x^2+x+1}{x}\implies 2x+1+x^{-1} &(1)\\ \\ \textit{differencate both sides} &y'=2-\dfrac{1}{x^2} &(2) \end{array} ok it seems we can do any implicit differentiation by...

The working I've tried is in the attachment.

$f: \mathbb{R^2} \rightarrow \mathbb{R}$, $f(x,y) = x^2+y^2-1$ $X:= f^{-1} (\{0\})=\{(x,y) \in \mathbb{R^2} | f(x,y)=0\}$ 1. Show that $f$ is continuous differentiable. 2. For which $(x,y) \in \mathbb{R^2}$ is the implicit function theorem usable to express $y$ under the condition $f(x,y)=0$...

I'm trying to compute a 2D Heat diffusion parabolic PDE: $$ \frac{\partial u}{\partial t} = \alpha \{ \frac{\partial^2 u}{\partial x^2} + \frac{\partial^2 u}{\partial y^2} \} $$ by the ADI method. I am actually trying to go over the example in this youtube video. The video is in another...

$\tiny{166.2.6.5}$ Find y' $$x^2-4xy+y^2=4$$ dy/dx $$2x-4(y+xy')+2yy'=2x-4y-4xy'+2yy'=0$$ factor $$y'(-4x+2y)=-2x+4y=$$ isolate $$y'=\dfrac{-2x+4y}{-4x+2y} =\dfrac{-x+2y}{-2x+y}$$ typo maybe not sure if sure if factoring out 4 helped

My attempt: According to the implicit function theorem as long as the determinant of the jacobian given by ∂(F,G)/∂(y,z) is not equal to 0, the parametrization is possible. ∂(F,G)/∂(y,z)=4yzMeaning that all points where z and y are not equal to 0 are possible parametrizations. My friend's...

Summary:: van der waals I have a pretty good understanding of implicit differentiation. However I'm stuck on a homework problem and could use some help. [P + (an^2)/V^2][V - nb] = nRT a,n,b,R are constants My professor wants me to take the implicit differentiation of P wrt...

I am new to calculus. I am doing well in my class. I just have a few questions about implicit differentiation. First, why do we call it "implicit" differentiation? Also, when we do it, why when we differentiate a term with a "y" in it, why do we have to multiply it by a dY/dX? What does that...

Homework Statement: Let ##\frac{1}{a}=\frac{1}{b}+\frac{1}{c}## If ##\frac{db}{dt}=0.2## ,## \frac{dc}{dt}=0.3## , Find ##\frac{da}{dt}## when a=80 , b=100 Homework Equations: - Since we are supposed to find ##\frac{da}{dt}##, I can deduce that: ## \frac{da}{dt}...

Help! Keep running this and getting different answers, and none are right. 2xy^8 + 7xy = 27 at the point (3,1)

Okay so I'm really not sure where I went wrong here; here's how I worked through it: $$\ln\left(y+x\right)=x$$ $$\frac{\frac{dy}{dx}+1}{y+x}=1$$ $$\frac{dy}{dx}+1=y+x$$ If ##\ln\left(y+x\right)=x## then ##y+x=e^x## and ##y=e^x-x## $$\frac{dy}{dx}=y+x-1$$ $$\frac{dy}{dx}=e^x-x+x-1$$...

Section ##3.8## talks about the gradient and smooth surfaces, defining when the directional derivative ##(\partial f/\partial\mathbf{u})(\mathbf{p})## takes maximum value and that when it equals ##0##, then ##\mathbf{u}## is a unit vector orthogonal to ##(grad\ f)(\mathbf{p})##.It also says that...

For Initial Value problems I want to implement an ODE solver for implicit Euler method with adaptive time step and use step doubling to estimate error. I have found some reading stuff about adaptive time step and error estimation using step doubling but those are mostly related to RK methods. I...

Would you please explain what an implicit function in general is? Why ##y^2+x^2=c## is assumed as implicit even though it can be expressed in terms of ##y##? ##y^2=c-x^2## and then ##y=\sqrt |x|## Thank you.

Homework Statement Find an equation that defines IMPLICITLY the parameterized family of solutions y(x) of the differential equation: 5xy dy/dx = x2 + y2 Homework Equations y=ux dy/dx = u+xdu/dx C as a constant of integration The Attempt at a Solution I saw a similar D.E. solved using the y=ux...

Hi, I am looking into some code in Python 3.7.2 that counts the number of appearances of in a message string. We are given a string. We then define an empty dictionary to be ultimately filled with the characters as the keys and the values will be (are the ) number of appearences of the...

Find the slope of the curve at the given point} $2y^8 + 7x^5 = 3y +6x \quad (1,1)$ Separate the variables $2y^8-3y=-7x^5+6x$ d/dx $16y^7y'-3y'=-35x^4+6$ isolate y' $\displaystyle y'=\frac{-35x^4+6}{16y^7-3}$ plug in (1,1)...

find dy/dx of $$5=2x^2y+7xy^2$$ ok didn't know how to set this up with the $5=$

Homework Statement Find the value of h'(0) if: $$h(x)+xcos(h(x))=x^2+3x+2/π$$ Homework Equations Chain Rule Product Rule The Attempt at a Solution I differentiated both sides, giving h'(x)+cos(h(x))-xh'(x)sin(h(x))=2x+3 Next I factored out and isolated h'(x) giving me...

Why implicit function is a function?

Homework Statement Find the equation of the tangent line to the graph of the given equation at the indicated point. ##xy^2+sin(πy)-2x^2=10## at point ##(2,-3)## Homework EquationsThe Attempt at a Solution Please see attached image so you can see my thought process. I think it would make more...

Why the implicit function is a function?

Homework Statement If ##x\sqrt{1+y} + y\sqrt{1+x } = 0##, then prove that ##\frac {dy} {dx} = \frac {-1}{(x-1)^2}##. 2.Relevant Equations: $$ \frac {dy} {dx} = - \frac {\left (\frac {\partial f}{\partial x} \right)} {\left( \frac {\partial f} {\partial y} \right)}.$$ 3...

Hello, I explain in my class a way to take a function and change it to implict function as: y - f(x) = 0 I see that way in Wikipedia, so I used it the class. But my students ask me question that I don't know to answer: 1. Are there more ways to take a function and change it to implict function...

Hello. My problem is as follows: Suppose x^4+y^2+y-3=0. a) Compute dy/dx by implicit differentiation. b) What is dy/dx when x=1 and y=1? c) Solve for y in terms of x (by the quadratic formula) and compute dy/dx directly. Compare with your answer in part a). I solved a) and b). a)=-4x^3/2y+1, and...

1. Homework Statement Question attached 2. The attempt at a solution Time-like killing vector is associated with energy. ## \frac{d}{ds} (\frac{\mu^2\dot{t}}{R^2})=0## Let me denote this conserved quantity by the constant ##E=\frac{\mu^\dot{t}}{R^2}## where ##\mu=\mu(z)## . similarly we...

The question is very general and could belong to another topic, but here it is. Suppose one wants to solve the set of differential equations $$ \frac{\partial x}{\partial t}=\frac{\partial H(x,p)}{\partial p},$$ $$\frac{\partial p}{\partial t}=-\frac{\partial H(x,p)}{\partial x},$$ with some...

Homework Statement Write an implicit Euler code to solve the system ##c'(x) = \epsilon c''(x)-kc(x)## subject to ##1-c(0)+\epsilon c'(0) = 0## and ##c'(1)=0##. Homework Equations Nothing out of the ordinary comes to mind. The Attempt at a Solution In the following code, there is central...

I need urgent help. I have this question: Use implicit differentiation to find an equation of the tangent line to the curve at the given point. \begin{equation} {x}^{2/3}+{y}^{2/3}=4 \\ \left(-3\sqrt{3}, 1\right)\end{equation} (astroid) x^{\frac{2}{3}}+y^{\frac{2}{3}}=4 My answer is...

Hello! (Wave) Which relation do the constants $a,b$ have to satisfy so that the implicit function theorem implies that the system of two equations $$axu^2v+byv^2=-a \ \ \ \ bxyu-auv^2=-a$$ can be solved as for u and v as functions $u=u(x,y)$ and $v=v(x,y)$ with continuous partial derivatives...

Hi PF! I am trying to plot a difficult implicit function, but for ease let's pretend that function is ##y^5\sqrt{1-x}+yx+1 = 0##. I want to plot ##Re(y)## as a function of ##x:x\in[0,2]##. I am using MATLAB. Do you think the best way to plot this is to assign ##x## a value in the domain, use...

For implicit differentiation, is dy/dx of x2+y2 = 50 the same as y2 = 50 - x2 ? From what I can take it, it'd be a no since. For x2+y2 = 50, d/dx (x2+y2) = d/dx (50) --- will eventually be ---> dy/dx = -x/y Where, y2 = 50 - x2 y = sqrt(50 - x2) dy/dx = .5(-x2+50)-.5*(-2x)

Hello, I wish to verify that the following pair ofcurves meet orthogonally. \[x^{2}+y^{2}=4\] and \[x^{2}=3y^{2}\] I recognize that the first is a circle, and the second contains 2 lines (y=1/3*x and y=-1/3*x). I thought to get an implicit derivative of the circle, and to compare it to the...

(a) Differentiate both sides of the equation with respect to x: $\displaystyle \begin{align*} \frac{\mathrm{d}}{\mathrm{d}x} \left[ y^3 + y + x\,y^2 \right] &= \frac{\mathrm{d}}{\mathrm{d}x} \left[ 10 + 4\sin{(x)} \right] \\ 3\,y^2\,\frac{\mathrm{d}y}{\mathrm{d}x} +...

How do I figure whether to do implicit differentiation or just explicit?? Thanks for the answer.

Homework Statement \dfrac{x^2}{x+y}=y^2+8 Homework Equations Quotient Rule: \dfrac{g(x)\cdot f'(x)-g'(x)\cdot f(x)}{(g(x))^2} Product Rule: f(x)\cdot g'(x)+g(x)\cdot f'(x) The Attempt at a Solution \dfrac{(x+y\cdot\dfrac{dy}{dx})(2x)-(1\cdot\dfrac{dy}{dx})(x^2)}{(x+y\cdot...

Homework Statement Hi, I am trying to follow the working attached which is showing that the average energy is equal to the most probable energy, denoted by ##E*##, where ##E*## is given by the ##E=E*## such that: ##\frac{\partial}{\partial E} (\Omega (E) e^{-\beta E}) = 0 ## MY QUESTION...

Hi I've been trying to get a hang of parameterizing a function (explicit or implicit). The main view seems to be that there is no general way of doing this, but this document seems to say that you can get solutions using differential equations...

Homework Statement For the given function z to demonstrate the equality: [/B]As you see I show the solution provided by the book, but I have some questions on this. I don't understand how the partial derivative of z respect to x or y has been calculated. Do you think this is correct? I...

Homework Statement I understand the proof of the implicit function theorem up to the point in which I have included a photo. This portion serves to prove the familiar equation for the implicit solution f(x,y) of F(x,y,z)=c. My confusion arises between equations 8.1-4 and 8.1-5 when it is stated...