Solving x²-1/4: Finding Negative Function Values and Domains

Question

Find the positive and negative domains of the function below:

y=x214 y=x^2-\frac{1}{4}

Then determine for which values of x x the following is true:

f(x) < 0

Step-by-Step Solution

To solve this problem, we will follow these steps:

  • Step 1: Solve the equation x2=14 x^2 = \frac{1}{4} to find critical points.
  • Step 2: Determine the sign of f(x)=x214 f(x) = x^2 - \frac{1}{4} in each interval between and beyond these points.
  • Step 3: Identify the interval where f(x)<0 f(x) < 0 .

Now, let's work through each step:
Step 1: Solve the equation x2=14 x^2 = \frac{1}{4} . The solutions are x=12 x = \frac{1}{2} and x=12 x = -\frac{1}{2} because solving this gives x=±14 x = \pm \sqrt{\frac{1}{4}} .
Step 2: To find where f(x)<0 f(x) < 0 , we need x2<14 x^2 < \frac{1}{4} . This is equivalent to finding where 12<x<12 -\frac{1}{2} < x < \frac{1}{2} . In this interval, f(x) f(x) is negative.
Step 3: The function y=x214 y = x^2 - \frac{1}{4} is negative for values of x x between these roots, i.e., for 12<x<12 -\frac{1}{2} < x < \frac{1}{2} .

Therefore, the solution is that the function is negative for 12<x<12-\frac{1}{2} < x < \frac{1}{2}.

Answer

-\frac{1}{2} < x < \frac{1}{2}