Problem 33 - Calculus of a Single Variable

Question

Finding a Derivative In Exercises \(33-54,\) find the derivative. $$ f(x)=e^{2 x} $$

Step-by-Step Solution

Answer

The derivative of the function \(f(x)=e^{2x}\) is \(f'(x)=2e^{2x}\).

Step 1 - Identify the inner and outer functions

Firstly, identify the inner and outer functions. In this case, the outer function is \(e^x\) and the inner function is \(2x\).

Step 2 - Apply the chain rule

Next, apply the chain rule given by [\(\frac{d}{dx}f(g(x)) = f'(g(x)) \cdot g'(x)\)]. The derivative of the outer function evaluated at the inner function (\(f'(g(x))\)) is \(e^{2x}\) (since the derivative of \(e^x\) is \(e^x\)). The derivative of the inner function (\(g'(x)\)) is \(2\).

Step 3 - Calculation

Multiply the result from step 2. So, \(\frac{df}{dx} = 2e^{2x}\).

Key Concepts

Chain Rule

The chain rule is a fundamental tool used in calculus to find the derivative of composite functions. It connects the rates of change of two functions that are composed together. When you have a function nested within another, like in our example, the chain rule helps you unravel them to find the derivative.

Here's a simplified way of understanding how the chain rule works:

• Identify the outer function and the inner function. The outer function is the main operation, while the inner function is the one embedded inside.
• Differentiate the outer function, keeping the inner function as it is initially.
• Multiply this by the derivative of the inner function.

In our case, we have an exponential function with an inner function of a simple linear form. Each of these components has its differentiation steps, making the chain rule imperative to use. It ensures that even when functions are layered, you can efficiently find their derivatives.

Exponential Function

Exponential functions are pervasive in mathematics and represent equations where a constant is raised to a variable exponent. The most common exponential function you encounter is the natural exponential function, denoted as \(e^x\).

The interesting property of the function \(e^x\) is that its derivative is itself, \(e^x\). This unique characteristic makes deriving exponential functions particularly straightforward. However, when you have an exponent that is not just \(x\), such as \(2x\) in \(e^{2x}\), the chain rule is necessary.

• The natural exponential base \(e\) is approximately equal to 2.718, but it's preferred to keep it as \(e\) for accuracy.
• Exponential growth and decay can be modeled effectively using these functions.

They arise naturally in various real-world phenomena, especially those involving continuous growth or decay, such as populations, investments, and radioactive decay.

Inner and Outer Functions

In many complex functions, you will find that they are made up of compositions of different types of functions. This is where the concepts of inner and outer functions come into play.

An outer function might be something very familiar, like \(f(x) = e^x\), a simple exponential function. The inner function is what you plug into the outer function, and it can be as simple as a linear function like \(2x\). The outer function dictates the overarching behavior of the equation, while the inner function modifies inputs before the outer function acts on them.

• For the function \(f(x)=e^{2x}\), \(e^x\) acts as the outer function.
• The expression within, \(2x\), is considered the inner function.
• Identifying these correctly is crucial for applying the chain rule.

Using the concept of inner and outer functions helps structure the process of differentiation, making the solution more methodical and understandable.