SOLUTION: An arch that supports a bridge is built in the shape of a downwards opening parabola. Its span is 100 ft and max height is 8 ft. Find the equation of the parabola that models the s
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-> SOLUTION: An arch that supports a bridge is built in the shape of a downwards opening parabola. Its span is 100 ft and max height is 8 ft. Find the equation of the parabola that models the s
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Question 970630: An arch that supports a bridge is built in the shape of a downwards opening parabola. Its span is 100 ft and max height is 8 ft. Find the equation of the parabola that models the situation. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! An arch that supports a bridge is built in the shape of a downwards opening parabola. Its span is 100 ft and max height is 8 ft.
Find the equation of the parabola that models the situation.
:
Using the form y = ax^2 + bx + c
:
Let axis of symmetry x=0, and the y intercept is the max height of 8 ft.
x intercept be -50 and +50; c = 8
:
x = -50, y = 0
-50^2*a - 50b + 8 = 0
2500a - 50b + 8 = 0
and x=+50; y=0
+50^2*a + 50b + 8 = 0
2500a + 50b + 8 = 0
:
use elimination
2500a - 50b + 8 = 0
2500a + 50b + 8 = 0
----------------------Adding eliminates b
5000a + 16 = 0
a =
a = -.0032
:
Equation: y = -.0032x^2 + 8
looks like this
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