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kandsbbf
 3 years ago
You live near a bridge that goes over a river. The underside of the bridge is an arch that can be modeled with the function y = –0.000471x² + .837x where x and y are measured in feet. How high above the river is the bridge (the top of the arch)? How long is the section of bridge above the arch?
The bridge is about 1,777.07 ft. above the river, and the length of the bridge above the arch is about 888.54 ft.
The bridge is about 371.85 ft. above the river, and the length of the bridge above the arch is about 1,777.07 ft.
The bridge is about 371.85 ft. above the river, and the length of the bri
kandsbbf
 3 years ago
You live near a bridge that goes over a river. The underside of the bridge is an arch that can be modeled with the function y = –0.000471x² + .837x where x and y are measured in feet. How high above the river is the bridge (the top of the arch)? How long is the section of bridge above the arch? The bridge is about 1,777.07 ft. above the river, and the length of the bridge above the arch is about 888.54 ft. The bridge is about 371.85 ft. above the river, and the length of the bridge above the arch is about 1,777.07 ft. The bridge is about 371.85 ft. above the river, and the length of the bri

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kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0The bridge is about 1,777.07 ft. above the river, and the length of the bridge above the arch is about 888.54 ft. The bridge is about 371.85 ft. above the river, and the length of the bridge above the arch is about 1,777.07 ft. The bridge is about 371.85 ft. above the river, and the length of the bridge above the arch is about 888.54 ft. The bridge is about 1,777.07 ft. above the river, and the length of the bridge above the arch is about 371.85 ft.

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok... to find the distance spanned by the arch you need to solve it so \[0.00047x^2 + 0.837x = 0... or... x(0.00047x  0.837)\] so x = 0 or 0.837/0.00047 the distance between the points will be the distance spanned. dw:1358113884987:dw

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok... do you know to differentiate..?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok... do you know how to find the line of symmetry of the curve...?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1what answer did you get got the distance spanned by the bridge..?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1oops missed a digit it should be 0.837/0.000471 and you should get 1777.07

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok so the parabola is symmetric and the highest point of the arch is on the line of symmetry... do you know how to find the line of symmetry..?

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0is it the line that goes down the middle?

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0so how do i figure it out?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok... so find half the distance spanned by the arch... then substitute that value into the equation for the bridge... that will give the height does that make sense..

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0soooo divide 1777.07 by 2?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1yep... then substitute it... the highest point is at the centre of the acrch

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1the original equation 0.000471x^2 + 0.837x

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0okay so when i divided it by 2 i got 888.535..... which number do i sub that for in the equation?

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0so do i sub that in for x?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1yes so its \[0.000471\times(888.535)^2 + 0.837\times888.535\]

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1what did you get for the height..? the length is 1777.07

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1ok... which answer has height 371.85 and length 1777.07

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1thats it.. well done

kandsbbf
 3 years ago
Best ResponseYou've already chosen the best response.0did we answer the last part of the question? How high above the river is the bridge (the top of the arch)? How long is the section of bridge above the arch?

campbell_st
 3 years ago
Best ResponseYou've already chosen the best response.1yes... you have all the answers you need height = 371.85 and length 1777.07
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