Downward-Opening Parabola Without X-Axis Intercepts: Analyzing Monotonicity Claims

Given a decreasing parabola that does not touch the X X -axis, it can be determined that the parabola is always increasing

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1

Understand the problem

Given a decreasing parabola that does not touch the X X -axis, it can be determined that the parabola is always increasing

2

Step-by-step solution

Given any quadratic function given by f(x)=ax2+bx+c f(x) = ax^2 + bx + c , it describes a parabola. Whether it opens upwards or downwards depends on the coefficient a a .

A parabola opens upwards when a>0 a > 0 , where it reaches a minimum at the vertex. It opens downwards when a<0 a < 0 , where the vertex is a maximum point. Since the problem specifies a "decreasing parabola," we can infer that a<0 a < 0 , indicating an opening downwards.

Importantly, if a parabola does not touch the x x -axis, its discriminant b24ac b^2 - 4ac is less than zero, indicating no real roots, and the parabola never crosses or touches the x-axis.

An opening downwards parabola has segments that are increasing on the left of the vertex and decreasing on the right. Therefore, it is incorrect to claim a downwards-opening parabola is always increasing, even if it doesn't touch the x x -axis.

Therefore, the statement, "the parabola is always increasing," in this context is False.

Thus, the correct answer is:

False

3

Final Answer

False

Practice Quiz

Test your knowledge with interactive questions

Note that the graph of the function shown below does not intersect the x-axis

The parabola's vertex is A

Identify the interval where the function is decreasing:

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