Math Problem Statement

Let f(x) = √2x − 3 + 4. What is the range of f(x)?

Solution

To find the range of the function f(x)=2x3+4f(x) = \sqrt{2x - 3} + 4, we need to determine the values that f(x)f(x) can take, given the expression for f(x)f(x).

Step 1: Understand the domain of the square root function

For the square root function 2x3\sqrt{2x - 3} to be valid (i.e., real-valued), the expression under the square root must be non-negative. So, we solve the inequality: 2x302x - 3 \geq 0 Solving for xx: 2x32x \geq 3 x32x \geq \frac{3}{2} Thus, the domain of f(x)f(x) is x32x \geq \frac{3}{2}.

Step 2: Analyze the behavior of the function

Now that we know the function is defined for x32x \geq \frac{3}{2}, let's explore the range of the function.

  • When x=32x = \frac{3}{2}, the expression inside the square root becomes: 2(32)3=33=0=0\sqrt{2\left(\frac{3}{2}\right) - 3} = \sqrt{3 - 3} = \sqrt{0} = 0 Therefore, f(32)=0+4=4f\left(\frac{3}{2}\right) = 0 + 4 = 4.

  • As xx \to \infty, the expression 2x3\sqrt{2x - 3} increases without bound, so f(x)f(x) also increases without bound. Therefore, as xx \to \infty, f(x)f(x) \to \infty.

Step 3: Conclusion

The smallest value of f(x)f(x) is 4, which occurs at x=32x = \frac{3}{2}, and there is no upper bound, so f(x)f(x) can take all values greater than or equal to 4.

Thus, the range of f(x)f(x) is: [4,)[4, \infty)

Would you like further details on this problem or have any questions? Here are some related questions to explore:

  1. How does the transformation +4+4 affect the graph of 2x3\sqrt{2x - 3}?
  2. What happens to the range if the square root is replaced with a different function (e.g., quadratic)?
  3. Can we determine the domain and range of f(x)f(x) without graphing it?
  4. How would the range change if the function was f(x)=2x34f(x) = \sqrt{2x - 3} - 4?
  5. What is the effect of modifying the coefficient inside the square root (e.g., f(x)=3x3+4f(x) = \sqrt{3x - 3} + 4)?

Tip: Always consider the domain of the square root function first, as it dictates the valid input values and helps in finding the range.

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Math Problem Analysis

Mathematical Concepts

Functions
Square Roots
Range of a Function

Formulas

f(x) = √(2x - 3) + 4

Theorems

Domain and Range of Square Root Functions

Suitable Grade Level

Grades 9-11