Question

College Algebra

Answer 1

do you know when ax^2+bx+c is maximum ?

Answer 2

I would just graph it to find the max.

Answer 3

graph is already given, so why do u wanto graph again :o

Answer 4

you can use that its max. when x = - b/a

Answer 5

Find the max of the function by derivating.

Answer 6

`algebra`

Answer 7

Can you explain the -b/a concept? I have heard it before and do not quite get it.

Answer 8

yeah, one way is to derivate,
but can you tell me whats the vertex of the parabola ax^2+bx +c ?

Answer 9

*b/2a concept is one way,

the other way, is as u said, find the x-intercepts first

Answer 10

The vertex is -h, k. So I guess that means completing the square. I like the x int idea too.

Answer 11

-b is -11
2a is 0.01 still right?

Answer 12

ax^2
-0.01 x^2
a= ... ?

Answer 13

Ok. Missed the -. -0.02x^2

Answer 14

so,
a = -0.01
b=11
-b/2a = ... ?

Answer 15

-11/-0.02

Answer 16

thats your 'x' when height is maximum

Answer 17

Thanks!!!!

Answer 18

to find max height
you plug this x in h(x)

Answer 19

you got the 2nd part too ?

Answer 20

Can't say I do.

Answer 21

means ?

Answer 22

I do need help with the second part.

Answer 23

ok, so the ball touches the water when h(x) = 0
right ?

Answer 24

Right

Answer 25

so,
11x-0.01x^2 = 0
solve this to get x

Answer 26

Does it have 2 answers?

Answer 27

one you will get x =0
discard it

Answer 28

1100

Answer 29

thats correct

Answer 30

Awesome.

Answer 31

Thanks.

Answer 32

welcome ^_^

Answer 33

you got 1100 as the second x-intercept,
wat do u get for max-height ?

Answer 34

Give me one sec and I will calculate it. Thanks for checking up on me ganeshie8!

Answer 35

I got 3025.

Answer 36

@ganeshie8

Answer 37

wasn't it this :
-11/-0.02
?

Answer 38

Yes, but I plugged that in for x in the original equation.

Answer 39

should be correct...

Answer 40

yeah, 3025 is correct :)

Answer 41

Thanks all!