Math Problem Statement

find boundaries for function f(x)=4sin(x)+cos(2x)

Solution

To find the boundaries (or range) of the function f(x)=4sin(x)+cos(2x)f(x) = 4\sin(x) + \cos(2x), let's break it down step by step:

  1. Rewriting the terms:

    • sin(x)\sin(x) oscillates between -1 and 1.
    • cos(2x)\cos(2x) also oscillates between -1 and 1, but with a double frequency.
  2. Analyze the range of individual terms:

    • The term 4sin(x)4\sin(x) ranges between 4(1)=44(-1) = -4 and 4(1)=44(1) = 4.
    • The term cos(2x)\cos(2x) ranges between -1 and 1.
  3. Considering their sum: The function is a sum of 4sin(x)4\sin(x) and cos(2x)\cos(2x). To find the overall range, we analyze the maximum and minimum values of their sum by considering different combinations of their individual maxima and minima.

  4. Maximizing and minimizing the sum:

    • Maximum value: When sin(x)=1\sin(x) = 1 and cos(2x)=1\cos(2x) = 1, the function is 4(1)+1=54(1) + 1 = 5.
    • Minimum value: When sin(x)=1\sin(x) = -1 and cos(2x)=1\cos(2x) = -1, the function is 4(1)+(1)=54(-1) + (-1) = -5.

Thus, the function f(x)=4sin(x)+cos(2x)f(x) = 4\sin(x) + \cos(2x) has a range from 5-5 to 55.

Conclusion:

The boundaries (range) of f(x)=4sin(x)+cos(2x)f(x) = 4\sin(x) + \cos(2x) are: [5,5][-5, 5]

Would you like further details or have any questions?

Here are 5 related questions:

  1. What is the range of g(x)=3sin(x)+2cos(x)g(x) = 3\sin(x) + 2\cos(x)?
  2. How does the range of f(x)=sin(x)+cos(2x)f(x) = \sin(x) + \cos(2x) differ from the original function?
  3. How do frequency and amplitude of trigonometric functions affect their range?
  4. What is the graphical representation of f(x)=4sin(x)+cos(2x)f(x) = 4\sin(x) + \cos(2x)?
  5. How would you find the boundaries of f(x)=asin(x)+bcos(2x)f(x) = a\sin(x) + b\cos(2x)?

Tip: The sum of sine and cosine functions often leads to periodic functions. Their maxima and minima depend on both amplitude and phase shift.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Functions
Oscillatory Behavior

Formulas

f(x) = 4sin(x) + cos(2x)
sin(x) ranges between -1 and 1
cos(2x) ranges between -1 and 1

Theorems

Range of trigonometric functions

Suitable Grade Level

Grades 10-12