3.1c Applications of Quadratic Functions
Ex. If the point (-3,9) is on the graph y = x2, determine where the point is after the
parabola undergoes:
1. a translation 5 units up
2. a translation 2 units right and 3 units down
3. a reflection in the x-axis and a vertical compression by a factor 1/4.
4. A vertical compression of y values by a factor 2/3, a reflection in the x-axis, then a
horizontal translation 12 units to the right.
Note: a horizontal reflection(across y-axis) changes sign of the x-value
a vertical reflection(across x-axis) changes the sign of the y-value
Ex. An archway has a width of 300 cm and a height of 220 cm.
a) Determine the quadratic function. Assume the origin is the center of the doorway.
b) How high is the arch 40 cm from the outer edge of the doorway?
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c) How would the quadratic function be different if the outer edge of the doorway
were considered the origin?
Ex. A small rocket is launched and reaches a maximum height of 3.2 m. It lands 10 m from the
launch pad. If it follows a parabolic path determine its equation. Use h for height and d
for distance from the launch pad.
Ex. Two towers 120 m tall and 500 m apart hold up a bridge. If the lowest part of the cable
is 70 m above the water, determine its equation.
Assignment: Sec. 3.1c p158 # 10-15, 16ab,17,20*
QUIZ NEXT CLASS!!!!
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