Implicit Definition and 520 Threads

  1. P

    Implicit differentation problem

    Homework Statement find the lines that are (a)tangent and (b)normal to the curve at the given point: x2 - √(3)xy + 2y2 = 5, (√3, 2) Homework Equations dy/dx The Attempt at a Solution i am completely confused about implicit differentiation and the chain rule. I've learned...
  2. V

    Doubt about Implicit differentiation

    Hi all, I was reading a paper in which implicit differentiation was used as follows x \in R, \lambda \in R Given G(x,\lambda) = 0 \frac{\partial G(x,\lambda)}{\partial x} \frac{\partial x}{\partial \lambda} + \frac{\partial G(x,\lambda)}{\partial \lambda} = 0 My doubt is...
  3. L

    Implicit Differentiation and product rule

    Hi, So, I am reviewing Cal III, and I have come across something that I do not understand regarding implicit differentiation with partial derivatives: x^3 + y^3 + z^3 + 6xyz = 1 implicit differentiation of z with respect to x: 3x^2 + 3z^2(dz/dx) + 6yz + 6xy(dz/dx) = 0 *notive the...
  4. K

    Second Derivative of an Implicit function

    How would you find the second derivative of an implicit function? y^2-x^2=16 Heres my attempt: 2y(dy/dx)-2x=0 2y(dy/dx)=2x 2y(dy/dx)/2y=2x/2y dy/dx= x/y This is only the first derivative. I think I'm suppose to plug in dy/dx back into the original equation. Am I on the right track?
  5. P

    Implicit vs explicit finite element solvers

    Hello, I was just reading about implicit vs explicit finite element solvers and have a question about the difference between them. I understand that the implicit solver has a linear approximation step that is used to force equilibrium. My question is does that make the explicit solver...
  6. K

    Finding Partial Derivatives with Implicit Differentiation

    Homework Statement Use implicit differentiation to find ∂z/∂x and ∂z/∂y yz = ln(x + z) The Attempt at a Solution I came up with (x+2)/(x+2)(1-xy-yz) Could someone please help me solve this. I know to treat y as a constant and to multiply all the derivatives of z by ∂z/∂x
  7. H

    Help: Implicit differentiation with initial values

    Homework Statement 2*y + sin(y) = x^4 + 4(x)^3 + (2(Pi) - 5), show that dy/dx = 16, when x = 1. Homework Equations The Attempt at a Solution So I implicitly differentiated it to be dy/dx(2 + cos(y)) = 4(x)^3 + 12(x)^2, and I end up with dy/dx = 16 / (2 + cos (y)) which means that...
  8. S

    Show that for the implicit midpoint rule?

    ||e_i+1|| <= ||e_i||+h||f( (t_i+t_i+1)/2, y_i+y_i+1)/2)-f((t_i+t_i+1)/2, y(t_i+t_i+1)/2))||+O(h^3). I need help about this question.if anybody able to guide me , I be thankful .
  9. M

    Implicit Differentiation: Finding Derivatives of an Implicit Function

    Homework Statement Assume that the following equation define the implicit function y=(x). Find the its derivative: x2 + 2xy - y2 = a2 y'=? y''=? Homework Equations \frac{dy}{dx} = -\frac{F_x}{F_y} The Attempt at a Solution so for the first derivative I express that equation as...
  10. K

    Implicit Differentiation and understanding the question?

    Hi, I am working on my differential equations excercises and I encountered 2 problems. First one is, I just wanted to check if I did this implicit differenriation right Homework Statement t^{2} \bullet y +y^{2} = C where is is a constant The Attempt at a Solution My solution is y...
  11. J

    Is the natural numbers implicit in the statement?

    In class we defined convergence as \forall\varepsilon>0\;\;\;\exists\mathrm{N}\epsilon\mathbf{N}\;\;\;\forall\mathrm{n}\geq\mathrm{N}\;\;\;\left|a_{n} \right|<\varepsilon So if a sequence {a_n} of real numbers converge to 0 if for every ε > 0 there is N s.t. |x_n| < ε for n ≥ N... Is the...
  12. A

    How could you use the implicit function theorem to prove something like this?

    Suppose you know that a function g(x,y,z) has a unique, non-degenerate minimum at some point (x_0,y_0,z_0). How could you go about using the implicit function theorem to prove that f(x,y,z) = g(x,y,z) + C h(x,y,z), where C is some constant, has a minimum at some point (x_c,y_c,z_c)? Could we...
  13. M

    Explicit Equations for Implicit Set at (0,0): First Partial Derivatives

    Homework Statement Show that the set defined by the equations x + y + z + w = sin(xyzw) x - y + z + w^2 = cos(xyzw) - 1 can be described explicitly by equation of the form (z, w) = f(x, y) near the point (0,0,0,0); find the first partial derivatives of f(x,y) at the point (0,0)...
  14. M

    Can the Implicit Function Theorem be Applied to Solve this System of Equations?

    Homework Statement Can the equation x^2 + y^2 + z^2 = 3, xy + tz = 2, xz + ty + e^t = 0 be solved for x, y, z as C^1 functions of t near (x, y, z, t) = (-1, -2, 1, 0)? Homework Equations The Attempt at a Solution The mixed-partial derivatives matrix I got was: [2x, 2y, 2z, 0]...
  15. H

    Find the derivative (Implicit)

    Homework Statement Find \frac{\partial\theta}{\partial y} z=rcos\theta x=rsin\theta\cos\phi y=rsin\theta\sin\phi r^2=x^2 + y^2 + z^2 The Attempt at a Solution We know cos\theta=\frac{z}{r}=\frac{z}{\sqrt{x^2 + y^2 + z^2}} So implicit differentiation says to differentiate...
  16. P

    What Is the Correct Approach to Solve These Implicit Differentiation Problems?

    Homework Statement 8x^2-10xy+3y^2=26 2. The attempt at a solution (8)(2x)-(-10x)y'+(y)(-10)+(3)(2y)y'=0 16x+10x(y')-10y+6y(y')=0 y'(10x+6y)+16x-10y=0 y'(10x+6y)=10y-16x y'=(10y-16x)/(10x+6y) y'=(5y-8x)/(5x+3y) I know I'm doing something wrong but I can't see it for...
  17. E

    Derivative of x^2+y^2=2y at (1,1) & Tangent Line

    Homework Statement What is the derivative of x^2 + y^2 = 2y, and find the tangent line to this equation at (1,1) Homework Equations The Attempt at a Solution I get y' = x / (1-y). However, how do I find the tangent line to this? When I plug in the values it divides by zero! (1 /...
  18. S

    How do I find f'(1) using implicit differentiation?

    "implicit differentiation" if [x][3] * f(x) + [(f(x))][3] + f([x][3]) = 3 and f(1)= 2 find f'(1) NEED HELP REVIEW QUESTION FROM EXAM REVIEW DONT KNOW WHAT TO DO
  19. M

    A run of the mill Implicit Differentiation

    Homework Statement Use Implicit Differentiation to find y' of the equation 5x^2+ 3xy+y^2=152. The attempt at a solution y'= (-10x-5y)/3x I would like to know if I did this right. I am not very confident in my math sometimes that why I came here. If i did this wrong will you please steer me...
  20. L

    Solve by Implicit Differentiation or Partial Differentiation?

    Homework Statement I've got a question more with the structure of how this problem is presented: If x^(sin y) = y^(cos x) Find \frac{dx}{dy}(\frac{pi}{4},\frac{pi}{4}) Homework Equations We have been taught to solve by implicit...
  21. I

    Implicit Differentiation: Finding dy/dt for x^2+3y^2+2y=10

    I've been working on this problem for a while and can't see my mistake, in the book the answer is stated as being 3, but I end up getting 13.5. Homework Statement If x^2+3y^2+2y = 10; dx/dt = 2, x=3 and y = -1 find dy/dt The Attempt at a Solution d/dt[x^2+3y^2+2y] = d/dt[10] 3x^2 (dx/dt) +...
  22. B

    How to Show Partial Derivative ∂z/∂x for Implicit Functions?

    Homework Statement Assume the F(x,y,z) = 0 defines z implicitly as a function of x anf y. Show that Homework Equations ∂z/∂x = -(∂F/∂x)/(∂F/∂z) The Attempt at a Solution I know this question is asking about the Implicit function theorem So I start with F(x,y,z) =0 define...
  23. D

    Should I use 2D or 3D graphs for Implicit Functions?

    I've began learning some Implicit Functions but graphing them seems to be a problem. I'm using MathGV for graphing. Should I choose 2D or 3D graphs? It's not graphing with 2D, and solving for x or y would be an even bigger problem. For instance, 3(x^2+y^2)^2 = 100xy will graph in 3D but is...
  24. M

    Find dy/dx by Substituting r for y and Theta for x | Simple Implicit Problem

    Homework Statement substituting r for y and theta for x as it will be easier to read find dy/dx if r=x^2 tan(2x) I don't know the answer Homework Equations The Attempt at a Solution d/dx (y) = d/dx [x^2 tan(2x)] dy/dx = dx/dx [2x] d/dx [tan (2x)] dy/dx = 2x sec^2...
  25. O

    Implicit Differentiation: Find Y

    Homework Statement Find y' Homework Equations The Attempt at a Solution My solution: it's correct?
  26. P

    Implicit Differentiation - Tangent Line & Horizontal Tangents

    Homework Statement Find an equation of the tangent line to this curve at the point (1, -2). Homework Equations The Attempt at a Solution 2y' = 3x^2+6x y' = 3x^2+6x y'=3/2x^2+3x y+2=3(x-1) y+2=3x-3 y=3x-5
  27. P

    Implicit Differentiation with Sin

    Homework Statement Homework Equations The Attempt at a Solution
  28. S

    What is the Second Derivative Using Implicit Differentiation?

    Use Implicit Differentiation to find y" if xy + y - x = 1 so far i got 1y + dy/dx - dx/dx = 1/dx then i did y + y' - 1 = 0 y' = 1-y i don't understand how to get the y" . i don't think i even have y' done right!
  29. H

    Implicit Differentiation Question

    Homework Statement Prove that \frac{dy}{dx}=\frac{y}{x} for \sqrt{\frac{x}{y}}+\sqrt{\frac{y}{x}}=10 x is not equal to y which is not equal to 0 The Attempt at a Solution Tried all the normal methods but none seem to work...anyone have any ideas?
  30. P

    How do I solve for y' in implicit differentiation problems?

    Homework Statement Find derivative of y with respect to x. Sin(xy) = Sinx Siny Homework Equations The Attempt at a Solution Use chain rule (product rule for inner function) to differentiate the left. Use product rule to differentiate the right and I get the following...
  31. Mentallic

    How to take the derivative of implicit functions

    I have been able to follow how to take the derivative of implicit functions, such as: x^2+y^2-1=0 Differentiating with respect to x 2x+2y\frac{dy}{dx}=0 \frac{dy}{dx}=\frac{-x}{y} Sure it's simple to follow, but I don't understand why the \frac{dy}{dx} is tacked onto the end of...
  32. J

    How do I find dy/dx for x2y+xy2=6 using implicit differentiation?

    Homework Statement find dy/dx for x2y+xy2=6 Homework Equations The Attempt at a Solution d/dx (x2y+xy2) = d/dx (6) x2*(dy/dx)+y*2x+x*2y(dy/dx)+2y=0 x2*(dy/dx)+y*2x+x*2y(dy/dx)=-2y (dy/dx)+y*2x+x*2y(dy/dx)=(-2y/x2) (dy/dx)+y*2x+(dy/dx)=(-2y/x2+2xy) I'm not sure what to do...
  33. D

    Implicit and Inverse Function Theorems

    What is a good book that gives a clear idea of what these theorems are? I am taking differential geometry, and I would like to try and get a better understanding of them. To be honest, my calculus sequence NEVER went over them, so I need to get these ideas under my belt.
  34. M

    Defining implicit function given a parametric function

    Homework Statement Given a continuous parametric function f : R2 -> R3 specifying a 2D surface in 3D space, define a continuous implicit function g : R3 -> R corresponding to the same surface. Homework Equations You’ll likely want to use the infimum function. You can ignore the...
  35. T

    How to Isolate Implicit Equations Involving Logs, Sines, and More?

    I was working on double integrals when I came across the equation: x^(3/2)=sin(x). There was no noticeable way to isolate the equation for x without having a function of x equal to x. I am wondering how to isolate equations involving logs, sines, etc when it is given in an implicit form. Using...
  36. T

    Unraveling the Implicit Differentiation of y=vx

    Homework Statement Consider y = 2a + ax find dy/dx dy/dx = a That is right is it not, as a is treated merly as a constantNow consider this question: Use the substitution y = vx to transform the equation: dy/dx = (4x+y)(x+y)/x² into x(dv/dx) = (2+v)² According to the mark scheme they...
  37. S

    Integration after implicit differentiation

    Homework Statement What is the integral of: y + x \frac{dy}{dx} The Attempt at a Solution I know that it is xy, after implicit differentiation. However, I cannot get it without prior knowledge of implicit differentiation.
  38. B

    Implicit differentitaion and finding coordinates

    Homework Statement dy/dx = [3(x^2)y - y^2] / [2xy - x^3] Find the x-coordinate of each point on the curve where the tangent line is vertical. Homework Equations original equation is x(y^2) - (x^3)y = 6 The Attempt at a Solution i set the denominator of the deriv. to 0, but i...
  39. S

    Chain rule for several variables: Implicit diff.

    Homework Statement Z is defined implicitly as a function of x,y by equation (z^2)x + 3xy^2 + e^((y^2)z) = 4. Find dz/dx Homework Equations dz/dx = -Fx/FzThe Attempt at a Solution Fx= z^2 + 3y^2 Fz=2zx+(y^2)e^((y^2)z) dz/dx= (z^2+3y^2)/[2zx+(y^2)e^((y^2)z)] I'm not sure if I used the partial...
  40. M

    Implicit differentiation - messed up somewhere

    Homework Statement find d^2y/dx^2 at (1,1) for: x^2y + x^2 -y^2 = 1 Homework Equations none The Attempt at a Solution i worked it all out but the answer I am getting is not an option. could someone show me where i made a mistake? I am not asking you to do the problem for me...
  41. T

    Why Does Rewriting an Equation Change the Implicit Derivative Result?

    when i took the derivative of X^2*Y^2-2x=6 i didn't get the same thing that i got when i took the derivative of y^2=(6+2x)/x^2 and all i did was rewrite the origional equation. why did rewriting the equation change my answer?
  42. A

    Help with 1 quick implicit differentiation problem

    Homework Statement what is the implicit differentiation ? Homework Equations 2sin(x)cos(y)=1 The Attempt at a Solution d/dx[2sin(x)cos(y)]= d/dx[1] 2cos(x)*-sin(y)*dy/dx=0 I haev a bad feeling i did this wrong...
  43. U

    Implicit differentiation homework

    hi i couldn't solve this question i think there is a mistake in it anyone can check it please ? http://img296.imageshack.us/img296/3716/13055173zr3.png
  44. madmike159

    Solve Implicit Functions: dy/dx of y^2+2y=x^3+3x-1

    Homework Statement Find dy/dx of y^2+2y = x^3+3x-1 Homework Equations The Attempt at a Solution I devided both sides by y so i got y+2 = x^3+3x-1/y then differentiating i got dy/dx = 3x^2 +3 / dy/dx I don't think this is right thanks for any help
  45. K

    Implicit Differentiation and coordinates

    Homework Statement Find the coordinates of the point in the first quadrant at which the tangent line to the curve x3-xy+y3=0 is parallel to the x-axis. SO: x= + y= + mtan=0 Homework Equations \frac{dy}{dx}=m_{tan} The Attempt at a Solution \frac{dy}{dx}=\frac{y-3x^{2}}{3y^{2}-x}=0 After I...
  46. N

    2 Problems. 1 regarding implicit differentiation

    1) A particle is moving along the curve y=3sqrt{3x+3}. As the particle passes through the point (2, 9), its x-coordinate increases at a rate of 2 units per second. Find the rate of change of the distance from the particle to the origin at this instant. 2) Use implicit differentiation to find...
  47. N

    How do I find the slope of a tangent line using implicit differentiation?

    Homework Statement Use implicit differentiation to find the slope of the tangent line to the curve 4x^2-3xy+1y^3=26 at the point (3,2) The Attempt at a Solution I attempted the problem and i came up with dy/dx= (-8x+4)/(3y^2) which is wrong. Need some help with this.
  48. D

    Implicit Differentiation w/ trig functions check

    Homework Statement Determine dy/dx when y*sin(x2)=5 The Attempt at a Solution y*2xcos(x2) dx/dx + sin(x2)*1 dy/dx = 0 2xy cos(x2)*dy/dx = -sin(x2) dy/dx = -sin(x2) / 2xy cos(x2) dy/dx = -2xy tan(x2)
  49. D

    Check request: Implicit Differentiation

    Homework Statement Find the value of dy/dx at x=2 when x2+xy=5 The Attempt at a Solution To find y: 22+2y=5 y=1/2 To find dy/dx: 2x(dx/dx)+x(dy/dx)+y(dx/dx)=0 2x+x(dy/dx)+y=0 (dy/dx)=(-2x-y) / x Plug in y and x: dy/dx=-2(2)-(1/2) / 2 dy/dx=-9/4 when x=2
  50. G

    Implicit Differentiation Check

    Homework Statement just a check, in Implicit Differentiation if you have let's say (x2+y2)2 would you get 2(x2+y2)(2x+2y(dy/dx)) or would it go out of the whole function in the chain rule and be 2(x2+y2)(2x+2y)(dy/dx) much appreciated.
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