Math Problem Statement

Verify that the IVT guarantees that there is a zero in the interval [0,1] for the function f(x)=2cox-3x. Then find the Zero

Solution

Step 1: Verify that the IVT applies

The Intermediate Value Theorem (IVT) states that if a function f(x)f(x) is continuous on a closed interval [a,b][a, b], and f(a)f(a) and f(b)f(b) have opposite signs, then there exists at least one c(a,b)c \in (a, b) such that f(c)=0f(c) = 0.

To apply the IVT for the function f(x)=2xcos(x)3xf(x) = 2x \cos(x) - 3x on the interval [0,1][0, 1], we need to:

  1. Check the continuity of f(x)f(x) on [0,1][0, 1].
  2. Evaluate f(0)f(0) and f(1)f(1).
  3. Confirm that f(0)f(0) and f(1)f(1) have opposite signs.

Step 2: Check the continuity of f(x)f(x)

The function f(x)=2xcos(x)3xf(x) = 2x \cos(x) - 3x involves basic operations (multiplication, subtraction) of continuous functions (since both xx and cos(x)\cos(x) are continuous everywhere). Therefore, f(x)f(x) is continuous on the interval [0,1][0, 1].

Step 3: Evaluate f(0)f(0) and f(1)f(1)

  • At x=0x = 0: f(0)=2(0)cos(0)3(0)=0f(0) = 2(0) \cos(0) - 3(0) = 0

  • At x=1x = 1: f(1)=2(1)cos(1)3(1)=2cos(1)32(0.5403)31.08063=1.9194f(1) = 2(1) \cos(1) - 3(1) = 2 \cos(1) - 3 \approx 2(0.5403) - 3 \approx 1.0806 - 3 = -1.9194

Step 4: Apply the IVT

  • f(0)=0f(0) = 0
  • f(1)1.9194f(1) \approx -1.9194

Since f(0)=0f(0) = 0, we already know that the function has a zero at x=0x = 0. Therefore, the IVT does not give us additional information on this particular interval, but since f(0)=0f(0) = 0, we can confidently say that x=0x = 0 is the zero of the function.

Conclusion:

By the Intermediate Value Theorem, the function does have a zero in the interval [0,1][0, 1], specifically at x=0x = 0.

Would you like further details or have additional questions? Here are some related questions to explore:

  1. What is the behavior of the function as xx increases from 0 to 1?
  2. How can you approximate zeros using numerical methods, like the bisection method?
  3. How would the IVT apply if the signs of f(0)f(0) and f(1)f(1) were different?
  4. What would happen if the function had a discontinuity at some point in the interval?
  5. How does the IVT work when dealing with more complex functions, such as trigonometric polynomials?

Tip: Always check whether the function is continuous on the interval in question when applying the IVT!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Intermediate Value Theorem
Continuity
Trigonometric Functions
Zero of a Function

Formulas

f(x) = 2xcos(x) - 3x

Theorems

Intermediate Value Theorem (IVT)

Suitable Grade Level

Grades 11-12