Determine X Values for y = -x² - 4 Less than Zero

Question

Given the function:

y=x24 y=-x^2-4

Determine for which values of x the following is true:

f\left(x\right) < 0

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Analyze the quadratic function given: y=x24 y = -x^2 - 4 .
  • Step 2: Analyze what y<0 y < 0 implies for the values of x x .

Now, let's solve it:

Step 1: Consider the given quadratic function y=x24 y = -x^2 - 4 . The function y=x2 y = -x^2 represents a downward-opening parabola due to the negative sign before x2 x^2 . The entire graph of the parabola, being shifted downward by 4 units with the term 4-4, will be wholly beneath the x-axis since there's no positive vertex or value. The vertex of the parabola is at (0,4) (0, -4) , which is already below zero.

Step 2: Because the quadratic term causes the graph to be a parabola opening downwards, it means that for any x x , y=x244 y = -x^2 - 4 \leq -4 , which is always less than zero. Thus, the inequality f(x)=x24<0 f(x) = -x^2 - 4 < 0 is satisfied for all real numbers x x .

Therefore, the solution is that the inequality is true for all x x .

Answer

All x