Question

vertex and roots of f(t)-16t^2+70t+4

Answer 1

f(t)=-16^2+70t+4
sorry

Answer 2

f'(t) should be -32t + 70
to find vertex set equal to 0

Answer 3

ahhh sorry it's -16t^2+70+4
we're supposed to find -b/2a to find t, then plug that in the find vertex, and then the roots i came up with were 35+or-sqrt1097 divided by 16

Answer 4

sorry about that, vertex looks good check the sqare root part in the quadratic formula

Answer 5

i get 35 +- sqrt(1289) divided by 16

Answer 6

b^2=35*35=1225
4ac=4(8)(4)=128
1225-128=1097? I think thats right, its asking for x-intercepts to graph it. how do i graph this?

Answer 7

redo the problem, this time looking closely at the signs.

Answer 8

-4 got it. thank you!!!!!!!

Answer 9

4ac = 4(-8)(2)

Answer 10

ooooh yeah. haha. thank you so much. but that means there are no x-intercepts right?

Answer 11

ok so now x = (35+- sqrt(1289))/16
those two x values are your x-intercepts
graph them as 2 points. (x1,0) and (x2,0)

Answer 12

get a graphing calculator to check your answers

Answer 13

but you can't graph that what we got for x

Answer 14

do you mean on a graphing calculator or by hand

Answer 15

so like the question is about baseball and how long it takes for the ball to hit the ground and after how many seconds. when i graph it, (0,4) is the y-int, (35/16, 1289/16) is the vertex (or the highest point the ball gets to) and then to figure out when the ball lands on the ground would be the x-int

Answer 16

the x-int would be one of the answers derived from the quadratic formula.

Answer 17

even if its like never ending full of decimals? would i just round it up?

Answer 18

yes round to two or three decimal places depending on what your teacher prefers.

Answer 19

oh ok. i think i got it this time then. thanks for all your help! =]

Answer 20

you're welcome. next time you ask for help it would be beneficial to state the entire problem not just the part you're stuck on. it gives me context. Thanks!