Parabola Analysis: Relationship Between Vertex Position and Function Values

Question

If the parabola is smiling and its vertex is above the x-axis, then it is always negative.

Step-by-Step Solution

To solve this problem, we'll analyze what is implied if the parabola is smiling (opening upwards) and if its vertex is located above the x-axis:

  • Step 1: Identify properties of the quadratic function. A "smiling" parabola in the form y=a(xh)2+ky = a(x-h)^2 + k with a>0a > 0 means the parabola opens upwards. The vertex (h,k)(h, k) will determine its intersection with the x-axis.
  • Step 2: Evaluate the impact of the vertex's location. If the vertex is above the x-axis, then k>0k > 0, indicating the vertex point itself is positive.
  • Step 3: Assess when the function is negative. For an upwards-facing parabola, yy takes on positive values when above the x-axis and negative values when below. If the vertex is above the x-axis, the quadratic will indeed become positive as xx moves away from the vertex, indicating that it cannot always be negative.
  • Step 4: Interpretation of statement: Given that the parabola could cross the x-axis in some regions other than the vertex and will achieve positive yy-values whenever the vertex is above the x-axis, the statement "the parabola is always negative" is incorrect.

Therefore, the given statement is Incorrect.

Answer

Incorrect