AP Calculus AB: 1.2.3 Parabolas
This content introduces parabolas as the graphs of second-degree polynomial functions, explaining how coefficients affect their direction, width, and position. It also covers simplifying expressions, handling undefined points, and using the distance formula derived from the Pythagorean theorem to calculate distances between points.
Parabolas
The graph of a second-degree polynomial expression is a parabola. A parabola consists of the set of all points in a plane that are equidistant from a fixed line (the directrix) and a fixed point not on the line (the focus).
When graphing functions, start by looking for ways to simplify their expressions. Always promise that the denominator will not equal zero when you cancel.
The distance formula is an application of the Pythagorean theorem. d = square root (x2-x1)^2 + (y2-y1)^2
Key Terms
Parabolas
The graph of a second-degree polynomial expression is a parabola. A parabola consists of the set of all points in a plane that are equidist...
note
In general, a parabola can be expressed by
f(x) = ax2 + bx + c. Each of the constants a, b, and c has a
different effect on the appea...
Does the parabola described by the
function
f(x)= -2(x^2+7) -4x^2 -9(5-x^2) open upwards or downwards?
upwards
A line intersects a parabola at the points (−2, 3) and (4, 11). What is the distance between the two points of intersection?
d = 10
Which of the following is the quadratic function whose graph is the parabola shown?
f(x) = x^2 -2x+2
Amanda and Laura are in the middle of a hiking trip and had a disagreement as to which direction to travel. Laura decides to hike due east in search of civilization and Amanda begins moving due south. In two hours Laura has moved 4 miles and Amanda has moved 5 miles. How far apart are the hikers at this time?
d = √41
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| Term | Definition |
|---|---|
Parabolas |
|
note |
|
Does the parabola described by the function f(x)= -2(x^2+7) -4x^2 -9(5-x^2) open upwards or downwards? | upwards |
A line intersects a parabola at the points (−2, 3) and (4, 11). What is the distance between the two points of intersection? | d = 10 |
Which of the following is the quadratic function whose graph is the parabola shown? | f(x) = x^2 -2x+2 |
Amanda and Laura are in the middle of a hiking trip and had a disagreement as to which direction to travel. Laura decides to hike due east in search of civilization and Amanda begins moving due south. In two hours Laura has moved 4 miles and Amanda has moved 5 miles. How far apart are the hikers at this time? | d = √41 |
What is the y-intercept of the graph of f(x) = -(x-2)^2 +3x +1 | -3 |
Does the parabola described by the | downwards |
What is the distance between the two points depicted in this graph? | d=√52 |
Which of the following is the graph of the parabola y = −2x ^2 + 4x ? | right side of y-axis, opens down 0,0), (1,2), (2,0 |
What is the distance between the two points (−1, 4) and (2, 5)? | √10 |
Find the distance between the two points -2,5) and (-3,7 | √5 |
Which of the following is the quadratic function whose graph is the parabola shown? | None of the above actual answer -4x^2-8x-4 |
What is the distance between the two points (1, 5) and (−3, 10)? | √41 |
Does the parabola described by the function | Upwards |