Horizontal Natural River
Math homework help? Urgent!?
A natural bridge is a stone arch over a river or stream. The longest natural bridge in the world is Rainbow Bridge in Utah. If the origin is placed at one end of the arch can be modeled by the equation:
h=-0.0425d^2+3.57d
h= height
d= horizontal distance
a)What is the width of the arch at the base?
b)What is the maximum height of the arch, to the nearest meter?
c)At a horizontal distance of the 10m from the vertex, what is the height of the arch, to the nearest meter?
I am supposed to find it using quadratics.
ANSWERS:
a)84
b)75
c)71
QUADRATIC FUNCTIONS PLEASE. GRAPHS ARE OF NO USE.
a) graph the function and find both zeros. the distance between the two zeros is the width of the bridge--essentially, if the bridge has one end at the origin, then the width will just be the x value of the other x-intercept
b)the graph will be an exponential function reflected over the xaxis so there will be a maximum point--the maximum height of the arch is the y value of the vertex of the function(you can use calc-->max on your graphing calculator)
c)find the x value(s) for when y is equal to 10 (that's what i would do for this question part)so make a separate function in the same graph as y=10 and find the intersection
Hope i helped! Good luck!