Math Problem Statement

Find partial z partial x at (0,0,0) f * x ^ 3 + z ^ 3 + x * e ^ (yz) + z * cos x = 0

Solution

We are asked to find the partial derivative of zz with respect to xx at the point (0,0,0)(0, 0, 0) for the implicit function:

f(x,y,z)=x3+z3+xeyz+zcosx=0.f(x, y, z) = x^3 + z^3 + x e^{yz} + z \cos x = 0.

To solve this, we will apply implicit differentiation with respect to xx, treating zz as a function of xx, i.e., z=z(x,y)z = z(x, y). Let's go step by step.

Step 1: Differentiate implicitly with respect to xx

We differentiate both sides of the equation f(x,y,z)=0f(x, y, z) = 0 with respect to xx:

x(x3+z3+xeyz+zcosx)=x(0).\frac{\partial}{\partial x} \left( x^3 + z^3 + x e^{yz} + z \cos x \right) = \frac{\partial}{\partial x} (0).

On the left-hand side, we apply the chain rule, remembering that zz is a function of xx, so terms involving zz will require us to include zx\frac{\partial z}{\partial x}.

Step 2: Differentiate each term

  1. x(x3)=3x2\frac{\partial}{\partial x} \left( x^3 \right) = 3x^2.
  2. x(z3)=3z2zx\frac{\partial}{\partial x} \left( z^3 \right) = 3z^2 \cdot \frac{\partial z}{\partial x}.
  3. x(xeyz)\frac{\partial}{\partial x} \left( x e^{yz} \right) requires the product rule: x(xeyz)=eyz+xeyz(yzx).\frac{\partial}{\partial x} \left( x e^{yz} \right) = e^{yz} + x \cdot e^{yz} \cdot \left( y \cdot \frac{\partial z}{\partial x} \right).
  4. x(zcosx)\frac{\partial}{\partial x} \left( z \cos x \right) also requires the product rule: x(zcosx)=zxcosxzsinx.\frac{\partial}{\partial x} \left( z \cos x \right) = \frac{\partial z}{\partial x} \cdot \cos x - z \cdot \sin x.

Step 3: Combine the derivatives

Putting everything together, we get the following equation:

3x2+3z2zx+eyz+xeyz(yzx)+zxcosxzsinx=0.3x^2 + 3z^2 \cdot \frac{\partial z}{\partial x} + e^{yz} + x \cdot e^{yz} \cdot \left( y \cdot \frac{\partial z}{\partial x} \right) + \frac{\partial z}{\partial x} \cdot \cos x - z \cdot \sin x = 0.

Step 4: Evaluate at (0,0,0)(0, 0, 0)

Now, substitute x=0x = 0, y=0y = 0, and z=0z = 0 into the equation:

  1. 3x2=3(0)2=03x^2 = 3(0)^2 = 0,
  2. 3z2zx=0zx=03z^2 \cdot \frac{\partial z}{\partial x} = 0 \cdot \frac{\partial z}{\partial x} = 0,
  3. eyz=e00=1e^{yz} = e^{0 \cdot 0} = 1,
  4. xeyz(yzx)=01(0zx)=0x \cdot e^{yz} \cdot ( y \cdot \frac{\partial z}{\partial x} ) = 0 \cdot 1 \cdot ( 0 \cdot \frac{\partial z}{\partial x} ) = 0,
  5. zxcosx=zxcos(0)=zx1\frac{\partial z}{\partial x} \cdot \cos x = \frac{\partial z}{\partial x} \cdot \cos(0) = \frac{\partial z}{\partial x} \cdot 1,
  6. zsinx=0sin(0)=0- z \cdot \sin x = - 0 \cdot \sin(0) = 0.

Thus, the equation simplifies to:

1+zx=0.1 + \frac{\partial z}{\partial x} = 0.

Step 5: Solve for zx\frac{\partial z}{\partial x}

From the simplified equation, we find:

zx=1.\frac{\partial z}{\partial x} = -1.

Final Answer:

The value of zx\frac{\partial z}{\partial x} at the point (0,0,0)(0, 0, 0) is 1\boxed{-1}.

Let me know if you'd like further details or have any questions.

Here are some follow-up questions:

  1. How does the chain rule apply in implicit differentiation?
  2. What happens when yy is not 0 in this problem?
  3. Can we generalize this method to find zy\frac{\partial z}{\partial y}?
  4. How would the solution change if the equation involved trigonometric functions of yy?
  5. Can we use this process to find second-order partial derivatives?

Tip: When differentiating implicitly, remember to treat the dependent variable (in this case, zz) as a function of the independent variables and apply the chain rule accordingly.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Partial Derivatives
Multivariable Calculus

Formulas

Chain rule for partial derivatives
Product rule: d(uv)/dx = u'v + uv'
Implicit differentiation: d/dx(f(x, z(x)) = 0

Theorems

Chain Rule for Partial Derivatives
Product Rule

Suitable Grade Level

Undergraduate Calculus (Advanced Placement or Early University Level)