If the graph of the quadratic polynomial is completely above or below ...
Since, the graph is completely above or below the x-axis, hence, it has no real roots. If a polynomial has real roots only then it cuts the x-axis. If it lies above or below, the roots are complex in nature.
If the graph of the quadratic polynomial is completely above or below ...
Explanation:
When the graph of a quadratic polynomial is completely above or below the x-axis, it means that the polynomial does not intersect the x-axis. In other words, the equation of the polynomial does not have any real roots. Instead, the roots of the polynomial are complex.
Quadratic Polynomial:
A quadratic polynomial is a polynomial of degree 2. It can be written in the form:
f(x) = ax^2 + bx + c
Where a, b, and c are constants and a ≠ 0.
Graph of Quadratic Polynomial:
The graph of a quadratic polynomial is a parabola. The vertex of the parabola can be found using the formula:
x = -b/2a
The parabola opens upwards if the coefficient of the x^2 term (a) is positive, and it opens downwards if a is negative. The vertex is the lowest or highest point on the parabola, depending on the direction it opens.
Nature of Roots:
The nature of the roots of a quadratic polynomial can be determined by considering the discriminant (D) of the quadratic equation:
D = b^2 - 4ac
If the discriminant is positive (D > 0), then the quadratic equation has two distinct real roots. This means that the graph of the quadratic polynomial intersects the x-axis at two different points.
If the discriminant is zero (D = 0), then the quadratic equation has one real root. This means that the graph of the quadratic polynomial touches the x-axis at one point.
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Conclusion:
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