Math Problem Statement

Find dy dx by implicit differentiation. x5 − xy + y2 = 8

Solution

We are tasked with finding dydx\frac{dy}{dx} by implicit differentiation for the equation:

x5xy+y2=8x^5 - xy + y^2 = 8

Step 1: Differentiate both sides with respect to xx

When differentiating, apply the chain rule where necessary, especially since yy is a function of xx.

  1. Differentiate x5x^5 with respect to xx: ddx(x5)=5x4\frac{d}{dx}(x^5) = 5x^4

  2. Differentiate xy-xy with respect to xx (using the product rule): ddx(xy)=(ddx(x)y+xdydx)=(y+xdydx)\frac{d}{dx}(-xy) = -\left(\frac{d}{dx}(x) \cdot y + x \cdot \frac{dy}{dx}\right) = -\left(y + x\frac{dy}{dx}\right)

  3. Differentiate y2y^2 with respect to xx (using the chain rule): ddx(y2)=2ydydx\frac{d}{dx}(y^2) = 2y \cdot \frac{dy}{dx}

  4. Differentiate the constant 8 with respect to xx: ddx(8)=0\frac{d}{dx}(8) = 0

Step 2: Combine the results

Now, substitute all the differentiated terms back into the equation:

5x4(y+xdydx)+2ydydx=05x^4 - (y + x\frac{dy}{dx}) + 2y \cdot \frac{dy}{dx} = 0

Step 3: Group terms involving dydx\frac{dy}{dx}

To isolate dydx\frac{dy}{dx}, first rearrange the terms:

5x4yxdydx+2ydydx=05x^4 - y - x\frac{dy}{dx} + 2y \frac{dy}{dx} = 0

Move the terms without dydx\frac{dy}{dx} to the other side:

xdydx+2ydydx=y5x4-x\frac{dy}{dx} + 2y\frac{dy}{dx} = y - 5x^4

Step 4: Factor out dydx\frac{dy}{dx}

Factor out dydx\frac{dy}{dx} from the left-hand side:

dydx(x+2y)=y5x4\frac{dy}{dx}(-x + 2y) = y - 5x^4

Step 5: Solve for dydx\frac{dy}{dx}

Finally, solve for dydx\frac{dy}{dx}:

dydx=y5x42yx\frac{dy}{dx} = \frac{y - 5x^4}{2y - x}

Thus, the derivative is:

dydx=y5x42yx\frac{dy}{dx} = \frac{y - 5x^4}{2y - x}

Would you like further clarification or any additional details?

Related Questions:

  1. How is implicit differentiation used in higher dimensions?
  2. Can you explain the product rule in detail?
  3. How do we apply the chain rule in implicit differentiation?
  4. What happens if yy is a function of more than one variable?
  5. How do you find the second derivative using implicit differentiation?

Tip:

When solving implicit differentiation problems, always remember to use the chain rule for terms involving yy.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Calculus
Product Rule
Chain Rule

Formulas

d/dx(f(x)g(x)) = f'(x)g(x) + f(x)g'(x) (Product Rule)
d/dx(y^n) = n * y^(n-1) * dy/dx (Chain Rule)

Theorems

Implicit Differentiation Theorem
Product Rule for Derivatives
Chain Rule for Differentiation

Suitable Grade Level

Grades 11-12 or Early College (Calculus)