Math Problem Statement

Write the function in the form y = f(u) and u = g(x). Then find dy/dx as a function of x. Given y = e^(2/7 * x).

Solution

Let's solve the problem step-by-step!

Problem Setup:

We are asked to rewrite the function y=e27xy = e^{\frac{2}{7}x} in the form: y=f(u)andu=g(x),y = f(u) \quad \text{and} \quad u = g(x), and then find the derivative dydx\frac{dy}{dx} using the chain rule.


Step 1: Rewrite the function in terms of uu.

We let: u=27x.u = \frac{2}{7}x. Then, the original function becomes: y=eu.y = e^u.

Now we have:

  • y=f(u)=euy = f(u) = e^u,
  • u=g(x)=27xu = g(x) = \frac{2}{7}x.

Step 2: Apply the Chain Rule to find dydx\frac{dy}{dx}.

Using the chain rule: dydx=dydududx.\frac{dy}{dx} = \frac{dy}{du} \cdot \frac{du}{dx}.

First, compute the individual derivatives:

  1. dydu=eu\frac{dy}{du} = e^u.
  2. dudx=27\frac{du}{dx} = \frac{2}{7}.

So: dydx=eu27.\frac{dy}{dx} = e^u \cdot \frac{2}{7}.


Step 3: Substitute u=27xu = \frac{2}{7}x back.

dydx=e27x27.\frac{dy}{dx} = e^{\frac{2}{7}x} \cdot \frac{2}{7}.


Final Answer:

The derivative is: dydx=27e27x.\frac{dy}{dx} = \frac{2}{7} e^{\frac{2}{7}x}.


Let me know if you have any questions about the steps! Below are five related questions that may interest you:

  1. How do you apply the chain rule to other exponential functions?
  2. What are the properties of the exponential function exe^x?
  3. How do you compute higher-order derivatives of exponential functions?
  4. How does the chain rule apply to logarithmic functions?
  5. What happens to the derivative if the base is not ee (e.g., axa^x)?

Tip: Always rewrite your function carefully when using the chain rule to avoid mixing variables.

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Math Problem Analysis

Mathematical Concepts

Calculus
Chain Rule
Exponential Functions

Formulas

Chain Rule: dy/dx = (dy/du) * (du/dx)
Derivative of an exponential function: d/dx(e^u) = e^u * (du/dx)

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12