Math Problem Statement

Find f''(x) at x = 1, if f(x) = 2e - cos(x - 1) + 1/e^x - ∛x.

Solution

To solve this problem, let's find f(x)f''(x) at x=1x = 1, given:

f(x)=2ecos(x1)+1exx3.f(x) = 2e - \cos(x - 1) + \frac{1}{e^x} - \sqrt[3]{x}.

Step 1: Compute the first derivative, f(x)f'(x)

The function is a sum of four terms, so we differentiate each term separately:

  1. 2e2e: This is a constant, so its derivative is 00.
  2. cos(x1)-\cos(x - 1): The derivative is sin(x1)\sin(x - 1).
  3. 1ex\frac{1}{e^x}: Rewrite as exe^{-x}, and the derivative is ex-e^{-x}.
  4. x3-\sqrt[3]{x}: Rewrite as x1/3-x^{1/3}, and the derivative is 13x2/3-\frac{1}{3}x^{-2/3}.

Thus: f(x)=sin(x1)ex13x2/3.f'(x) = \sin(x - 1) - e^{-x} - \frac{1}{3}x^{-2/3}.

Step 2: Compute the second derivative, f(x)f''(x)

Now, differentiate f(x)f'(x) term by term:

  1. sin(x1)\sin(x - 1): The derivative is cos(x1)\cos(x - 1).
  2. ex-e^{-x}: The derivative is exe^{-x}.
  3. 13x2/3-\frac{1}{3}x^{-2/3}: The derivative is 29x5/3\frac{2}{9}x^{-5/3}.

Thus: f(x)=cos(x1)+ex+29x5/3.f''(x) = \cos(x - 1) + e^{-x} + \frac{2}{9}x^{-5/3}.

Step 3: Evaluate f(x)f''(x) at x=1x = 1

Substitute x=1x = 1 into f(x)f''(x):

  1. cos(11)=cos(0)=1\cos(1 - 1) = \cos(0) = 1,
  2. e1=1ee^{-1} = \frac{1}{e},
  3. 2915/3=29\frac{2}{9} \cdot 1^{-5/3} = \frac{2}{9}.

Thus: f(1)=1+1e+29.f''(1) = 1 + \frac{1}{e} + \frac{2}{9}.

Final Answer:

f(1)=1+1e+29.f''(1) = 1 + \frac{1}{e} + \frac{2}{9}.

Would you like further simplification or explanations? Here are some related questions to deepen your understanding:

  1. How do we find higher-order derivatives for composite functions like cos(x1)\cos(x - 1)?
  2. What role does ee play in differentiation?
  3. Can the cube root term x3\sqrt[3]{x} create undefined derivatives for x0x \leq 0?
  4. Why is exe^x unique among exponential functions in calculus?
  5. How do we handle fractional powers when computing derivatives?

Tip: Always simplify the function before differentiating to minimize errors!

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Math Problem Analysis

Mathematical Concepts

Differentiation
Second Derivatives
Exponential Functions
Trigonometric Functions

Formulas

Derivative of e^x: d/dx(e^x) = e^x
Derivative of cos(x): d/dx(cos(x)) = -sin(x)
Derivative of x^n: d/dx(x^n) = n*x^(n-1)

Theorems

Basic Rules of Differentiation

Suitable Grade Level

Undergraduate (Calculus I)