Look at the following function:
Determine for which values of the following is true:
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Look at the following function:
Determine for which values of the following is true:
To solve this problem, we'll follow these steps:
Now, let's work through each step:
Step 1: Calculate the discriminant .
For the quadratic , we have:
The discriminant is . Because , the quadratic has no real roots, meaning it never crosses the x-axis.
Step 2: Since the discriminant is negative and the coefficient is negative, the parabola opens downward.
With no x-intercepts, the vertex is the point where the maximum value occurs. However, for a downward opening parabola with , it resides above the x-axis for all .
We conclude that the entire parabola remains below the x-axis across all real , meaning the function is negative for all .
Therefore, the solution to the problem is that the function is negative for all .
The function is negative for all .
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 \( f\left(x\right) > 0 \).
A negative discriminant means the quadratic has no real roots - the parabola never touches or crosses the x-axis. It stays entirely on one side of the x-axis.
Look at the coefficient of ! If a > 0, the parabola opens upward (always positive with no roots). If a < 0, it opens downward (always negative with no roots).
While testing values helps verify, the discriminant method gives you the complete answer instantly! Testing a few points might mislead you about the function's behavior everywhere.
Double-check your arithmetic: . Remember that two negatives multiply to positive: 4(-1)(-20) = 80.
No! Since the discriminant is negative, there are no real solutions to . The function never equals zero - it's always negative.
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