Find the domain of $y=\sqrt{3 x-8}$.


A$x \geq \frac{8}{3}$
B$x>-\frac{8}{3}$
C$x \geq \frac{3}{8}$
D$x \geq-\frac{8}{3}$

Verified Answer :

  • Identify that the radicand of a square root must be non-negative for the function to be defined in real numbers: \(3x - 8 \geq 0\).
  • Solve the linear inequality by isolating \(x\): \(3x \geq 8\), which simplifies to \(x \geq \frac{8}{3}\).
  • Conclude that the domain of the function is \(x \geq \frac{8}{3}\).
  • The final answer is \(\boxed{x \geq \frac{8}{3}}\).

Explanation

  1. Determining the Condition for the Domain

To find the domain of the function \(y = \sqrt{3x - 8}\), we need to determine the set of all real values of \(x\) for which the function is defined. In the set of real numbers, the square root of a number is defined if and only if the expression inside the square root (the radicand) is greater than or equal to zero. Thus, we must have the radicand \(3x - 8 \geq 0\).

  1. Solving the Inequality for x

To isolate the variable \(x\), we first add 8 to both sides of the inequality:
\[3x - 8 + 8 \geq 0 + 8\]
\[3x \geq 8\]
Next, we divide both sides by 3:
\[x \geq \frac{8}{3}\]
This gives us the range of values for \(x\) that satisfy the condition for the square root function to be defined.

  1. Conclusion and Final Result

Based on our calculation, the function \(y = \sqrt{3x - 8}\) is defined for all \(x\) such that \(x \geq \frac{8}{3}\). Comparing this result with the provided options, it matches the first option. Therefore, the domain of the function is \(x \geq \frac{8}{3}\).

Examples

The concept of domain is essential in many fields. For example, if you are designing a computer program that calculates the square root of a user's input, the program must ensure that it only receives non-negative numbers to avoid errors. By defining the domain as \(x \geq \frac{8}{3}\), you establish the valid inputs that the program can process safely, preventing crashes or invalid outputs. This is a fundamental aspect of robust software development and mathematical modeling.