polynomials answer check

[shy quiver]

please @ me

[shy quiver]

<@&286206848099549185>

[stray umbra]

jeez ur right

[shy quiver]

actually?

@stray umbra

[stray umbra]

yes u said x is approximately 2.26

[shy quiver]

how do ik ur not just saying im righ

right*

[stray umbra]

u r

do u want proof

[shy quiver]

ig that would be good

im not very trusting

[stray umbra]

ok well we start from the volume formula 𝑉
(
𝑥
)

𝑥
(
40
−
2
𝑥
)
(
30
−
2
𝑥
)$

𝑉(𝑥)=𝑥(40−2𝑥)(30−2𝑥)

[shy quiver]

umm is this how its supposed to look like?

[stray umbra]

no

then u expand the expresion

[shy quiver]

ok now i trust

[stray umbra]

first multiply the two parentheses (40−2𝑥)(30−2𝑥)

[shy quiver]

i just needed to know if yk what ur doing yk?

[stray umbra]

oh ok

[shy quiver]

ok i have another question

[stray umbra]

ok

[stray umbra]

wht it is?

[shy quiver]

so when it comes to worded problems im as dumb as a 5 year old

[stray umbra]

do u want me to solve it or explain it

[shy quiver]

explain how to get the answer

[stray umbra]

k

[shy quiver]

solving is against the rules

so idk where to start

[stray umbra]

look at where the graph hits zero it touches the horizontal axis at t = 0 and t = 700 those are the times when the barrier is not depressed at all

[shy quiver]

what does depressed mean

[shy quiver]

thats the domain of the graph

[stray umbra]

it just mean how far the barrier gets pushed inward when a car hits it if the graph says the barrier is depressed 85 nm then tht means the car pushed the barrier in by 85 millimeters

[shy quiver]

ohh ok

so now what

[stray umbra]

the formula alr has a zero multiplied in front so when t = 0 the whole expression becomes 0 tht is y the graph touches the axis at t = 0 automatically

[shy quiver]

this part is worded weird:
expression becomes 0 tht is y the graph touches the axis at t = 0 automatically

[stray umbra]

bc the formula starts with t x something plugging in t = 0 makes the whole thing 0 so the graph must hit the axis at t = 0

is tht better

@shy quiver is tht better

[shy quiver]

yes

but were trying to find a

[stray umbra]

yes tht is wht we are doing

[shy quiver]

ok

[stray umbra]

we are trying to find a and the way we can do tht is by looking at where the graph hits zero the formula alr gives us a zero at t = 0 bc of the t in front so the other zero on the graph must come from (𝑡−𝑎)2 the graph hits zero again at t = 700 so tht means a = 700

[shy quiver]

i dont get it

[stray umbra]

where dont u follow?

[shy quiver]

(𝑡−𝑎)2 the graph hits zero again at t = 700 so tht means a = 700

wait thats (t-a)^2 not (t-a)*2

[stray umbra]

yes thanks for realising my mistake

[shy quiver]

wait i think i get it

we are looking where it is the only possible time for the graph to hit 0

which is 0 and 700

but what i dont get is why is a 700

[stray umbra]

(t - a)^2 is only zero when t = a the graph hits zero at t = 700 so tht must be the value of a

[shy quiver]

ok

[stray umbra]

want me to explain b now

[shy quiver]

isnt it the same as 7d?

[stray umbra]

?

[shy quiver]

question 7d is where i asked if its right or wrong

[shy quiver]

.

[stray umbra]

so ur asking is part b the same idea is 7d

[shy quiver]

yes

[stray umbra]

well yeah its the same type of step is 7d in 7d u plug a volume into the formula and solve for x in part b we are plugging in t = 100 and f(100) = 85 into the formula and solve for k

[shy quiver]

ok simple enough

[stray umbra]

good u think u can solve it?

[shy quiver]

ill try it but i might need help

[stray umbra]

ok i'll be here

[shy quiver]

do i really have to guess where 100 ms is gonna be?

[stray umbra]

no u dont quess for part b they give u the value at t = 100 it is 85 mm u just plug t = 100 and f(100) = 85 into the formula and slove for k

[shy quiver]

ok

@stray umbra ?

that is all ik

[stray umbra]

good the only problem is u wrote it backwards its 85 = k(100)(100 - 700)^2

very good

u squared 600 wrong

u just added two zeros is all nothing to big

its 360,000

[shy quiver]

the answer is 85/36 000 000

f(t)=85/36 000 000 t(t-700)^2

[stray umbra]

good job u multiplied 360k by 100 and got 36m good job

[shy quiver]

no i looked at the answer book

[stray umbra]

y

[shy quiver]

cause u said its 360,000

[stray umbra]

typo

[shy quiver]

i got 36m by (100)(100-700)^2

[shy quiver]

lol

ok i got the first part but the second part how do i get that

[stray umbra]

wym

[shy quiver]

how do i get f(t)=85/36 000 000 t(t-700)^2

wait i get it

since k=85/36 000 000
we just sub it in

and we get the answer

[stray umbra]

good job

anything else

[shy quiver]

but why instead of t we dont right 100

since t is 100

[stray umbra]

we only plug in 100 once to solve for k after tht we go back to the original formula f(t) = k t(t−700)² we replace k not t since the final function has to work for any t not just 100

[shy quiver]

ok thanks

its 2am for me might need to sleep

[stray umbra]

ok gn yw

[shy quiver]

i finished the whole chapter

thanks

.close

[sudden crypt]

Solved

Post marked as solved by @shy quiver.

Use .unsolved if this was a mistake.