Question

I need help understanding this, its about ax^2 + bx + c

Answer 1

A Labrador leaps over a hurdle. The function f(t) represents the height of the Labrador above the ground, in inches, at t seconds:

f(t) = -16t2 + 20t

A foxhound jumps over the same hurdle. The table shows the height of the foxhound above the ground g(t), in inches, at t seconds:
Time (t) g(t)
0 0
0.4 7.44
0.6 9.24
0.75 9.76
1.0 9
1.50 0

Part A: Compare and interpret the maximum of f(t) and g(t)? (4 points)

Part B: Which function has a greater x-intercept? What do the x-intercepts of the graphs of f(t) and g(t) represent? (4 points)

Part C: Determine the y-intercepts of both functions, and explain what this means in the context of the problem. (2 points)

Answer 2

How do i solve this i understand how to do quadratics and how to use the formula but i dont know where to start

Answer 3

@kropot72

Answer 4

Do you know how to get the max of f(x)?

Answer 5

yes

Answer 6

is there another formula to it?

Answer 7

ok, show me!!

Answer 8

just take derivative and let it =0 to get t, then , plug back to get f(t)

Answer 9

so i plug 0.75 into f(t)=-16t^2+20t?

Answer 10

to get the maximum?

Answer 11

it's not 0.75!!

Answer 12

i was thinking it was either that or 9.76

Answer 13

redo!!
f'(t) = -32t+20
f'(t) =0 --> -32t+20=0--> t =0.625

Answer 14

how can you get 0.75?

Answer 15

ohhh i see what you did but how did you get the .625 part?

Answer 16

I said it above!! or you can get it by: the maximum value is the vertex of the parabola, right? and it is defined by x = -b/2a = -20/(2*(-16) = 0.625

Answer 17

honestly it was something i saw while trying to get the answers online >.<

Answer 18

oh, you are not calculus student, right? just algebra one, right?

Answer 19

thank you so much can i do the same with g(t)

Answer 20

yes

Answer 21

no, no!!! for g(t), you already have it, they give you the highest point is at t =0.75 and g(t) =9.76

Answer 22

woudnt 1.0 and 1.5 be the highest point ?

Answer 23

so, you just find out the highest point of f(t) by plugging 0.625 back to f(t) to find the highest point of f(t), then compare them

Answer 24

so f(t) is needed to figure out g(t)

Answer 25

so g(t) has the higher x intercept

Answer 26

They give you 2 different formats of quadratic. Actually, they are the same, just represented in different ways.
for f(t), they give you standard formula
for (gt), they give you the specific time and specific altitude. It's kind of the step to graph the function
And they ask you to compare them
Their goal is to make sure you can master both types

Answer 27

H ow do i know if its a maximum or a minimum and how would i compare it?

Answer 28

how*

Answer 29

.625 is the maximum but can the other be a maximum too?