Math Problem Statement

Use implicit differentiation to calculate the derivative ∂z ∂x if xyz + x2y + y4z = 0.

Solution

We are given the equation:

xyz+x2y+y4z=0xyz + x^2y + y^4z = 0

We need to find zx\frac{\partial z}{\partial x} using implicit differentiation. Here's the step-by-step process.

Step 1: Differentiate both sides of the equation with respect to xx.

Since z=z(x,y)z = z(x, y), we must apply the product rule when differentiating terms involving zz.

  1. First term: xyzxyz: Using the product rule: ddx(xyz)=ddx(x)yz+xddx(yz)\frac{d}{dx}(xyz) = \frac{d}{dx}(x) \cdot yz + x \cdot \frac{d}{dx}(yz)

    • The first part is yzyz, since ddx(x)=1\frac{d}{dx}(x) = 1.
    • For the second part, use the product rule again: ddx(yz)=yddx(z)=yzx\frac{d}{dx}(yz) = y \cdot \frac{d}{dx}(z) = y \cdot \frac{\partial z}{\partial x} So, the derivative of xyzxyz becomes: yz+xyzxyz + xy \frac{\partial z}{\partial x}
  2. Second term: x2yx^2y: Again, apply the product rule: ddx(x2y)=ddx(x2)y+x2ddx(y)\frac{d}{dx}(x^2y) = \frac{d}{dx}(x^2) \cdot y + x^2 \cdot \frac{d}{dx}(y) Since yy is independent of xx, this simplifies to: 2xy2xy

  3. Third term: y4zy^4z: Here, only zz depends on xx, so we use the chain rule: ddx(y4z)=y4zx\frac{d}{dx}(y^4z) = y^4 \frac{\partial z}{\partial x}

Step 2: Differentiate the right-hand side (constant 00).

ddx(0)=0\frac{d}{dx}(0) = 0

Step 3: Combine the results.

Putting everything together:

yz+xyzx+2xy+y4zx=0yz + xy \frac{\partial z}{\partial x} + 2xy + y^4 \frac{\partial z}{\partial x} = 0

Step 4: Solve for zx\frac{\partial z}{\partial x}.

Group the terms involving zx\frac{\partial z}{\partial x}:

xyzx+y4zx=yz2xyxy \frac{\partial z}{\partial x} + y^4 \frac{\partial z}{\partial x} = -yz - 2xy

Factor out zx\frac{\partial z}{\partial x}:

zx(xy+y4)=yz2xy\frac{\partial z}{\partial x}(xy + y^4) = -yz - 2xy

Finally, solve for zx\frac{\partial z}{\partial x}:

zx=yz2xyxy+y4\frac{\partial z}{\partial x} = \frac{-yz - 2xy}{xy + y^4}

This is the derivative zx\frac{\partial z}{\partial x} using implicit differentiation.


Would you like more details on any part of the solution?

Here are 5 related questions for further exploration:

  1. How would you calculate zy\frac{\partial z}{\partial y} for the same equation?
  2. Can you explain the product rule in more detail?
  3. What happens if we substitute specific values for xx, yy, and zz into this result?
  4. How does implicit differentiation differ from regular differentiation?
  5. What if the equation involved more complex functions like trigonometric terms?

Tip: Always apply the product rule carefully when differentiating terms that involve products of functions of different variables.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Multivariable Calculus
Partial Derivatives
Product Rule

Formulas

Product Rule: d(uv)/dx = u(dv/dx) + v(du/dx)
Chain Rule: d(f(g(x)))/dx = df/dg * dg/dx

Theorems

Implicit Differentiation
Product Rule

Suitable Grade Level

College-level Calculus