For the function f(x) = sin(x) + cos(x), find the x-coordinate of the maximum po

Practice Questions

Q1
For the function f(x) = sin(x) + cos(x), find the x-coordinate of the maximum point in the interval [0, 2π].
  1. π/4
  2. 3π/4
  3. 5π/4
  4. 7π/4

Questions & Step-by-Step Solutions

For the function f(x) = sin(x) + cos(x), find the x-coordinate of the maximum point in the interval [0, 2π].
Correct Answer: 3π/4
  • Step 1: Identify the function we are working with, which is f(x) = sin(x) + cos(x).
  • Step 2: Find the derivative of the function, f'(x). The derivative is f'(x) = cos(x) - sin(x).
  • Step 3: Set the derivative equal to zero to find critical points: cos(x) - sin(x) = 0.
  • Step 4: Rearrange the equation to get tan(x) = 1.
  • Step 5: Solve for x. The general solution for tan(x) = 1 is x = π/4 + nπ, where n is any integer.
  • Step 6: Determine the specific solutions in the interval [0, 2π]. For n = 0, x = π/4; for n = 1, x = π/4 + π = 5π/4.
  • Step 7: Evaluate the function f(x) at the critical points x = π/4 and x = 5π/4 to find which gives the maximum value.
  • Step 8: Calculate f(π/4) and f(5π/4). Compare the values to find the maximum.
  • Step 9: Identify that the maximum occurs at x = 3π/4, which is the x-coordinate of the maximum point in the interval [0, 2π].
  • Differentiation – Understanding how to find the derivative of a function to locate critical points.
  • Critical Points – Identifying where the derivative equals zero to find potential maximum or minimum points.
  • Interval Testing – Evaluating the function within a specified interval to determine maximum and minimum values.
  • Trigonometric Functions – Applying knowledge of sine and cosine functions and their properties.
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