Chapter 4: Problem 60
\(59-60 .\) Find the second derivative of each function. $$ f(x)=e^{-x^{6} / 6} $$
Short Answer
Expert verified
The second derivative is \( f''(x) = (-5x^4 + x^{10}) e^{-x^6/6} \).
Step by step solution
01
Find the First Derivative
Given the function \( f(x) = e^{-x^6/6} \), we first need to find its first derivative \( f'(x) \). Use the chain rule for finding the derivative of the exponential function. Let \( u = -x^6/6 \), then \( f(x) = e^u \). The derivative of \( e^u \) with respect to \( x \) is \( e^u \cdot \frac{du}{dx} \). So, find \( \frac{du}{dx} = -x^5 \) using the power rule. Thus, \( f'(x) = e^{-x^6/6} \cdot (-x^5) = -x^5 e^{-x^6/6} \).
02
Find the Second Derivative
Now, we need to find the second derivative \( f''(x) \). Start by differentiating the first derivative \( f'(x) = -x^5 e^{-x^6/6} \) again using the product rule. Let \( u = -x^5 \) and \( v = e^{-x^6/6} \), where \( f'(x) = u \cdot v \). The product rule states \( (uv)' = u'v + uv' \). Differentiating \( u = -x^5 \) gives \( u' = -5x^4 \). For \( v = e^{-x^6/6} \), \( v' = e^{-x^6/6} \cdot (-x^5) \). Applying the product rule: \[ f''(x) = (-5x^4) e^{-x^6/6} + (-x^5) (-x^5 e^{-x^6/6}) = (-5x^4 + x^{10}) e^{-x^6/6} \]
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Exponential Function Derivative
The derivative of an exponential function is a vital part of calculus. When dealing with exponential functions like \( f(x) = e^{u}\), the derivative can be found using a simple rule. The function \( e^{u} \) is unique because its derivative is itself, \( e^{u} \), times the derivative of the exponent \( u \).
This rule can be stated as follows:
This rule can be stated as follows:
- Identify \( u \), the exponent in the exponential function.
- Compute \( \frac{du}{dx} \), the derivative of \( u \) with respect to \( x \).
- The derivative of \( e^{u} \) is \( e^{u} \cdot \frac{du}{dx} \).
Chain Rule
The chain rule is a powerful tool for finding the derivative of composite functions. Whenever you differentiate a function within another function, it's time to use the chain rule.
To use the chain rule:
To use the chain rule:
- First, determine the outer function and the inner function. In our case, \( f(x) = e^{-x^6/6} \), where \( e^u \) is the outer function and \( -\frac{x^6}{6} \) is the inner function \( u \).
- Differentiate the outer function with respect to \( u \) and the inner function \( u \) with respect to \( x \).
- Multiply the two derivatives to get the derivative of the original function.
Power Rule
The power rule is a foundational principle in calculus when differentiating expressions with exponents. This rule is straightforward and highly effective for finding derivatives quickly.
To apply the power rule, simply:
To apply the power rule, simply:
- If you have \( x^n \), multiply by the exponent \( n \), and reduce the power by one.
- This yields \( \frac{d}{dx}x^n = n \cdot x^{n-1} \).
Product Rule
The product rule is essential for differentiating expressions where two functions are multiplied together. It helps us when the derivative involves a product of two functions, say \( u(x) \) and \( v(x) \).
According to the product rule:
According to the product rule:
- If \( y = uv \), then the derivative is \( y' = u'v + uv' \).
- First, find the individual derivatives, \( u' \) and \( v' \).
- Use these derivatives to apply the formula.