Math Problem Statement

If g = f', determine:

d/dx 6x^2 * e ^ (x * f(2x))

Solution

To find the derivative of 6x2exf(2x)6x^2 \cdot e^{x \cdot f(2x)}, we will apply the product rule and the chain rule.

Let’s break it down step by step:

Step 1: Apply the Product Rule

The product rule states: ddx(uv)=uv+uv\frac{d}{dx} (u \cdot v) = u'v + uv' Here, let:

  • u=6x2u = 6x^2
  • v=exf(2x)v = e^{x \cdot f(2x)}

We need to find uu' and vv'.

Step 2: Find uu'

The derivative of u=6x2u = 6x^2 is straightforward: u=ddx6x2=12xu' = \frac{d}{dx} 6x^2 = 12x

Step 3: Find vv'

Now we need to differentiate v=exf(2x)v = e^{x \cdot f(2x)}. This involves applying the chain rule: v=ddxexf(2x)=exf(2x)ddx(xf(2x))v' = \frac{d}{dx} e^{x \cdot f(2x)} = e^{x \cdot f(2x)} \cdot \frac{d}{dx} (x \cdot f(2x))

To differentiate xf(2x)x \cdot f(2x), use the product rule again: ddx(xf(2x))=ddxxf(2x)+xddxf(2x)\frac{d}{dx} (x \cdot f(2x)) = \frac{d}{dx} x \cdot f(2x) + x \cdot \frac{d}{dx} f(2x)

  • The derivative of xx is 1.
  • The derivative of f(2x)f(2x) using the chain rule is f(2x)2=g(2x)2f'(2x) \cdot 2 = g(2x) \cdot 2 (since g(x)=f(x)g(x) = f'(x)).

So, we have: ddx(xf(2x))=f(2x)+2xg(2x)\frac{d}{dx} (x \cdot f(2x)) = f(2x) + 2x \cdot g(2x)

Thus: v=exf(2x)(f(2x)+2xg(2x))v' = e^{x \cdot f(2x)} \cdot (f(2x) + 2x \cdot g(2x))

Step 4: Combine using the Product Rule

Now, using the product rule: ddx(6x2exf(2x))=uv+uv\frac{d}{dx} \left( 6x^2 \cdot e^{x \cdot f(2x)} \right) = u'v + uv'

Substituting the values we found for uu', vv, and vv': =12xexf(2x)+6x2exf(2x)(f(2x)+2xg(2x))= 12x \cdot e^{x \cdot f(2x)} + 6x^2 \cdot e^{x \cdot f(2x)} \cdot (f(2x) + 2x \cdot g(2x))

Final Answer:

ddx(6x2exf(2x))=12xexf(2x)+6x2exf(2x)(f(2x)+2xg(2x))\frac{d}{dx} \left( 6x^2 \cdot e^{x \cdot f(2x)} \right) = 12x \cdot e^{x \cdot f(2x)} + 6x^2 \cdot e^{x \cdot f(2x)} \cdot (f(2x) + 2x \cdot g(2x))

Let me know if you'd like to see more details or have any questions!

Related Questions:

  1. How is the product rule used in differentiation?
  2. Can you explain how the chain rule applies to exponential functions?
  3. What is the significance of f(x)=g(x)f'(x) = g(x) in this problem?
  4. How do you differentiate a composite function involving another function?
  5. How would the derivative change if f(x)f(x) was a specific function, like sin(x)\sin(x)?

Tip:

Always check for opportunities to apply both the product and chain rules in combination, as in this problem!

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Math Problem Analysis

Mathematical Concepts

Calculus
Product Rule
Chain Rule
Exponential Functions
Derivative of Composite Functions

Formulas

Product Rule: (u * v)' = u'v + uv'
Chain Rule: d/dx e^(f(x)) = e^(f(x)) * f'(x)

Theorems

Product Rule in Differentiation
Chain Rule in Differentiation

Suitable Grade Level

Undergraduate Calculus