Look at the function below:
Determine for which values of the following is true:
We have hundreds of course questions with personalized recommendations + Account 100% premium
Look at the function below:
Determine for which values of the following is true:
To solve this problem, we first consider the function . This is a quadratic function, and we can analyze the parabola it represents.
The standard form of a quadratic function is , where in our case , , and .
To determine if the function has any negative values, we first find the vertex of the parabola. The vertex form of a quadratic function is determined by:
Plugging in our values:
.
The -coordinate of the vertex can be found by substituting back into the equation:
.
The vertex of the parabola is , which means the minimum point of the parabola is above the x-axis at .
Next, we assess whether there are any real roots by finding the discriminant :
.
Since the discriminant is negative (), this indicates the parabola does not intersect the x-axis at any real point. Therefore, it never dips below the x-axis.
Given that the vertex is above the x-axis and the discriminant is negative, the quadratic function is never negative for any real .
The function has no negative values.
The function has no negative values.
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 \( f\left(x\right) > 0 \).
Use the discriminant test! If and , the parabola opens upward and never touches the x-axis, so it has no negative values.
A negative discriminant means the quadratic has no real roots - the parabola doesn't cross the x-axis at any point. This is key information for determining if the function can be negative!
The vertex shows the minimum point of an upward-opening parabola. If this lowest point is above the x-axis (), then the entire function stays positive.
Yes! If (parabola opens downward) and the discriminant is negative, the function is always negative. But in our case, , so it opens upward.
Look at the coefficient of ! If it's positive (like our +1), the parabola opens upward (U-shape). If negative, it opens downward (∩-shape).
Get unlimited access to all 18 The Quadratic Function questions, detailed video solutions, and personalized progress tracking.
Unlimited Video Solutions
Step-by-step explanations for every problem
Progress Analytics
Track your mastery across all topics
Ad-Free Learning
Focus on math without distractions
No credit card required • Cancel anytime