Math Problem Statement

Suppose that f(x) = x^7 e^x. Find f'(1).

Solution

The function given in the image is f(x)=x7exf(x) = x^7 e^x, and you're asked to find f(1)f'(1), which means we need to compute the derivative of the function f(x)f(x) and then evaluate it at x=1x = 1.

Step 1: Differentiate the function

We use the product rule because f(x)=x7exf(x) = x^7 e^x is the product of two functions: f(x)=u(x)v(x)f(x) = u(x) \cdot v(x) where:

  • u(x)=x7u(x) = x^7
  • v(x)=exv(x) = e^x

The product rule states: (fg)=fg+fg(f \cdot g)' = f' g + f g'

First, differentiate u(x)=x7u(x) = x^7:

u(x)=7x6u'(x) = 7x^6

Then, differentiate v(x)=exv(x) = e^x:

v(x)=exv'(x) = e^x

Now, apply the product rule: f(x)=u(x)v(x)+u(x)v(x)f'(x) = u'(x)v(x) + u(x)v'(x) f(x)=7x6ex+x7exf'(x) = 7x^6 e^x + x^7 e^x

Step 2: Evaluate f(x)f'(x) at x=1x = 1

Now, substitute x=1x = 1 into the derivative: f(1)=7(1)6e1+(1)7e1f'(1) = 7(1)^6 e^1 + (1)^7 e^1 f(1)=7e+ef'(1) = 7e + e f(1)=8ef'(1) = 8e

So, the answer is: f(1)=8ef'(1) = 8e

Would you like more details or have any questions about this process?

Here are 5 related questions to expand your understanding:

  1. How is the product rule used to differentiate functions?
  2. What is the derivative of exe^x, and why is it the same?
  3. Can the chain rule be combined with the product rule in similar problems?
  4. What is the second derivative f(x)f''(x) for this function?
  5. How would you compute the derivative if the power of xx was a function of xx?

Tip: Always check whether a function is a product of two functions when differentiating—it can simplify the problem using the product rule.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Product Rule

Formulas

Product rule: (f ⋅ g)' = f' g + f g'
Derivative of x^n = n x^(n-1)
Derivative of e^x = e^x

Theorems

Product Rule
Power Rule

Suitable Grade Level

Grades 11-12 or College Calculus