Parabola Analysis: Finding Positive Values Where f(x) > 0 at Vertex Point

Parabola Analysis with Downward Opening

The graph of the function below intersects the X-axis at one point A (the vertex of the parabola).

Find all values of x x

where f(x)>0 f\left(x\right) > 0 .

AAAX

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Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

The graph of the function below intersects the X-axis at one point A (the vertex of the parabola).

Find all values of x x

where f(x)>0 f\left(x\right) > 0 .

AAAX

2

Step-by-step solution

To identify the conditions where f(x)>0 f(x) > 0 , we need to analyze the nature of the quadratic function as represented on the provided graph.

Based on the problem, the graph intersects the x-axis exactly at one point, recognized as point A, the vertex. In a quadratic function ax2+bx+c ax^2 + bx + c , if the vertex intersects at the x-axis and nowhere else, it means the graph is tangent to the x-axis at that vertex.

To determine if the function is positive, examine the orientation: - If a>0 a > 0 , the parabola opens upwards, making it have a minimum at the vertex. - If a<0 a < 0 , the parabola opens downwards, making it have a maximum at the vertex. Given that the problem states the parabola intersects the x-axis only at the vertex, the parabola opens downward. This is inferred from the phrased graph where no areas reach above the x-axis.

Therefore, the function never reaches a value greater than zero, as the parabola is concave down, and the vertex sits on the x-axis.

Conclusively, the range where f(x)>0 f(x) > 0 is nonexistent given the parameters of the problem.

Therefore, the solution is that there are no such values.

3

Final Answer

No such values

Key Points to Remember

Essential concepts to master this topic
  • Rule: Downward parabola touching x-axis never goes above zero
  • Technique: When vertex is on x-axis, f(x) ≤ 0 for all x values
  • Check: Maximum value at vertex A equals zero, so f(x) > 0 is impossible ✓

Common Mistakes

Avoid these frequent errors
  • Assuming parabola has positive values near vertex
    Don't think that points near the vertex will be positive just because it's the 'special point' = wrong conclusion! A downward parabola with vertex on x-axis has its maximum value at zero. Always remember that downward parabolas decrease as you move away from the vertex.

Practice Quiz

Test your knowledge with interactive questions

The graph of the function below intersects the X-axis at points A and B.

The vertex of the parabola is marked at point C.

Find all values of \( x \) where \( f\left(x\right) > 0 \).

AAABBBCCCX

FAQ

Everything you need to know about this question

How can I tell if a parabola opens upward or downward from the graph?

+

Look at the direction of the curve! If the parabola looks like a smile (∪), it opens upward. If it looks like a frown (∩), it opens downward. In this problem, the parabola opens downward.

Why does touching the x-axis at one point mean f(x) is never positive?

+

When a parabola touches the x-axis at exactly one point, that point is the vertex. For a downward-opening parabola, the vertex is the highest point. If the highest point is on the x-axis (where y = 0), then all other points are below it!

What's the difference between f(x) > 0 and f(x) ≥ 0 for this problem?

+

f(x) > 0 means strictly greater than zero (positive values only). f(x) ≥ 0 includes zero itself. In this problem, f(x) = 0 at point A, but f(x) is never greater than zero.

Could this parabola have any positive values if I can't see the whole graph?

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No! The problem states the parabola intersects the x-axis at one point only. This mathematical fact tells us the complete behavior: it's a downward parabola with vertex on the x-axis, so no positive values exist anywhere.

How do I know this isn't an upward parabola that just looks downward in the picture?

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The key clue is that it intersects the x-axis at exactly one point. If it were upward-opening, the vertex would be the minimum, and the parabola would have positive values everywhere else. Since we see it touches only once, it must open downward.

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