#help-39

1 messages · Page 113 of 1

sharp smelt
#

x is prime.

trying to express this using logical quantifiers

sharp smelt
#

This essentially means $x= 1 \cdot x$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

sharp smelt
#

and that's the only prime factorisation of the same

#

no?

#

Hello charbit

grizzled dust
sharp smelt
#

hmm

#

yeah

#

makes sense

#

thanks

#

$\exists x( d|x \implies d=x \vee d=1)$$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

sharp smelt
#

like this?

merry carbon
#

Remember you're making a claim about x (that it's prime), rather than [trying to/] say[/ing] "primes exist"

sharp smelt
#

mhm

merry carbon
#

Also "what's d?" catGiggle

sharp smelt
#

right

#

a divisor

#

of x

#

hmm

#

so what exactly is wrong with my statement?

#

It's just a convolted way of saying primes exist?

rustic gate
#

it's not well formed

sharp smelt
#

mhm

#

maybe as $x = y \cdot z$ and then $y\neqz$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

sharp smelt
#

$\exist x( x= y \cdot z \land y \neq z\land ( y \vee z =1))$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

sharp smelt
#

ooh

#

yeah, I'm lost 😭

sharp smelt
#

$\exists d( d|x \implies d=x \vee d=1)$

#

like so?

rustic gate
#

the statement that "x is prime" depends on x, so you don't need to introduce x

sharp smelt
#

I see, so just there exists a d such that d|x...

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

rustic gate
#

is that how you tell a number is prime?

sharp smelt
#

no

#

a number is prime iff its prime factorisation is unique

#

sorr

#

one minute

rustic gate
#

9 is prime because there exists a number d=9 such that 9 | 9, and 9 = 9

#

that's not true is it

sharp smelt
#

no

#

a number is prime if the only d|x are 1 and x itself

#

is that right?

quiet tendon
#

yes

#

uniqueness of prime factorizations applies to all integers > 1, not just primes, as per the fundamental theorem of arithmetic

sharp smelt
#

$\exists d(d|x \land (d=x \vee d=1))$

#

is this it?

#

if not could I have another hint ? sadcat

rustic gate
#

a number x is prime if the only divisors are x and 1

sharp smelt
#

yes

rustic gate
#

here, you're only testing that fact for a single divisor d

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

rustic gate
#

this was on the right track

#

$\exists d( d|x \implies d=x \vee d=1)$

jolly parrotBOT
rustic gate
#

the problem is that you've only asked for a single d to satisfy this

sharp smelt
#

I don't follow, I just enclose the 2nd part in brackets and I'm done, right?

rustic gate
#

for x to be a prime, any divisor of x must satisfy the condition in the right

sharp smelt
#

yes

#

but here d is a free variable , right

rustic gate
#

and you've only asked for one d to exist

#

i can pick the d to be x

sharp smelt
#

so I introduce another variable similar to d

rustic gate
#

no

#

you quantify over d with a universal quantifier

#

every divisor of x must satisfy the condition

sharp smelt
#

$\exists d( d|x \implies \forall ( d=x \vee d=1))$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

rustic gate
#

no thats not well formed

#

and what i mean is

#

$\forall d( d|x \implies d=x \vee d=1)$

jolly parrotBOT
rustic gate
#

every divisor of x must satisfy the condition

sharp smelt
#

yes, I get that bit, but I'm not sure of how to write it

rustic gate
#

\forall d

sharp smelt
rustic gate
#

no that expression is not well formed

#

the forall doesn't have anything it's attached to

sharp smelt
rustic gate
#

you want to universally quantify over d

sharp smelt
#

ah, I see

rustic gate
#

because you want to make a statement about all divisors of x

#

not just some particular one of your choosing

sharp smelt
#

got it

#

thanks!

#

.close

pearl pondBOT
#
Channel closed

Closed by @sharp smelt

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

astral pebble
#

im not sure how to do this

pearl pondBOT
astral pebble
#

i do know that i have to calculate gpe and ke

#

but my topic doesnt have any formula for friction and im not sure how to minus off my friction so well kinda need some help with the friction

pearl pondBOT
#

@astral pebble Has your question been resolved?

pearl pondBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

maiden swan
pearl pondBOT
#

@maiden swan Has your question been resolved?

charred ocean
pearl pondBOT
# maiden swan
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

plucky nebula
#

how would you determine if a subset is closed under addition and multiplication comprehensively

sharp vigil
#

for addition: define two arbitrary elements of the set, noting that they satisfy the condition of the subset. find out whether their sum necessarily satisfies the condition as well

#

the specifics depend on how the subset is defined

plucky nebula
#

ah okay

#

the lecturer just did an example of this lmao

sharp vigil
#

your lecturer combined the addition and multiplication closures into one expression

plucky nebula
#

yeah he said it is an alternative subspace test

sharp vigil
#

so to show it's closed under addition, we need f1 + f2 to belong to the set, and for it to be closed under multiplication we need λf1 to belong. so λf1 + f2 is in the space if and only if the previous two conditions are met

plucky nebula
#

yeah that makes sense

#

he only also proved the non-existence of the non-empty set by showing that the 0 vector of the vector space V is also part of the subspace S

sharp vigil
#

0 is a convenient vector to check since if it is not in the space then either:

  1. the subset is empty
  2. the subset is not closed under addition and scalar multiplication
plucky nebula
#

makes sense

pearl pondBOT
#

@plucky nebula Has your question been resolved?

pearl pondBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

halcyon plank
#

The table shows three values of x and their corresponding values of y, where y = f(x) + 4 and f is a quadratic function.
What is the y-coordinate of the y-intercept of the graph = f(z) in the Y-plane?

Ans: f(x)=-4(x-21)(x-25)-12. but why?

gloomy hare
#

and you were answered each time

dapper kraken
#

actually bro

#

last time i saw you you straight up refused the method lmao

dapper kraken
dapper kraken
#

meow i love cats

halcyon plank
pearl pondBOT
#

@halcyon plank Has your question been resolved?

pearl pondBOT
#

@halcyon plank Has your question been resolved?

pearl pondBOT
#

@halcyon plank Has your question been resolved?

pearl pondBOT
#

@halcyon plank Has your question been resolved?

pearl pondBOT
#

@halcyon plank Has your question been resolved?

last moth
halcyon plank
last moth
#

That didn't really answer my question. I'm trying to get enough information to help you, but I can't really help if I don't know what you're looking for and what's already been explained to you.

halcyon plank
#

I was taught the vertex form quadratic equation

#

and basically graphing points on a graphing calculator

#

i was also taught the factored form quadratic equation but surprisingly i couldn't understand it, so just like u can see lol. im trying to understand it

last moth
#

I think the answer you wrote has a typo. It should be -4(x-21)(x-25)-12.

#

Are you trying to figure out how to get from that answer into a factored form?

last moth
#

Okay

#

The first step would be to expand everything out

#

So, you want to multiply (x-21) by (x-25)

#

Do you know how to do that?

halcyon plank
#

Yes

last moth
#

Okay so then what do you get

halcyon plank
#

we dont need to expand tho

#

but ok

#

x^2-46x+525

last moth
#

We do if we want to figure out how to factor it

#

Okay good

#

Next we need to multiply by -4

#

So that gives us -4x^2 + 184x - 2100

#

And finally subtract 12 and we get

#

-4x^2 + 184x - 2112

halcyon plank
#

but why do we subtract by 12

last moth
#

do you mean why do we subtract by 12?

halcyon plank
#

yes]

last moth
#

It's because there's a - 12 in the original answer we got

halcyon plank
#

like why is there a -12

last moth
halcyon plank
#

no

#

kinda

#

im only asking why is there -12

#

i understand from where do the other terms come

#

but not "-12"

#

here's where i'm confused

last moth
#

OK so let's try seeing what we get without the -12

halcyon plank
#

okay

last moth
#

So, f(x) = -4(x-21)(x-25)

#

Our equation is y = f(x) + 4

#

So that gives us y = -4(x-21)(x-25) + 4

#

And now let's try plugging in our values of x=21, x=23, x=25

halcyon plank
#

okay

last moth
#

If we plug in x=21, the first term becomes 0, so we get that y = 4

#

Same with if we plug in x=25, we get y = 4

#

Does that make sense

halcyon plank
last moth
#

What part doesn't make sense

halcyon plank
#

okay but why did you choose to put -12

#

why not any other number?

last moth
#

We haven't gotten to that part yet

#

Does what I said so far make sense

halcyon plank
#

yes

last moth
#

Okay so

#

Also if we plug in x=23, we get 20

#

So we can make a table of our results
x y
21 4
23 20
25 4

#

If we compare that to the table that we want

#

x y
21 -8
23 8
25 -8

#

You can see that we're off by 12 each time

#

4 - 12 = -8
20 - 12 = 8
4 - 12 = -8

#

So we need to subtract f(x) by 12 in order to get the table we want

halcyon plank
#

okay

halcyon plank
last moth
#

We're just plugging in numbers and then comparing them with the numbers in the table we want

halcyon plank
#

okay

last moth
#

I explained it in detail to help you, but the actual method is pretty short

#

Once you get used to it

halcyon plank
#

tysm

last moth
#

Np

halcyon plank
#

.close

pearl pondBOT
#
Channel closed

Closed by @halcyon plank

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

steel atlas
#

hello

pearl pondBOT
steel atlas
#

i need help with this

#

I don't know what I should do in this step.

ivory swallow
#

ok

steel atlas
ivory swallow
#

i can't read that

#

let me try to latex it

steel atlas
#

this is the answer

ivory swallow
#

$$\frac{5}{7} \cdot \frac{a^{11}}{a^7} \cdot \frac{1/b^8}{1/1} \cdot \sqrt[3]{2^3 \cdot 3^3 \cdot 3^2 \cdot a^2 \cdot b^{18}}$$

jolly parrotBOT
#

Mr. Gamer 🇵🇸

ivory swallow
#

is that right

steel atlas
#

yes

ivory swallow
#

alright i'll let another helper take over because i'm gonna be hungover

pearl pondBOT
#

@steel atlas Has your question been resolved?

pearl pondBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

stoic imp
#

let $f(x) = \frac{24e^{x}}{3e^{x} + 1}$ find the range of f

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

stoic imp
#

,, \lim_{x \to +\infty} \frac{24e^{x}}{3e^{x} + 1} \= \frac{24}{3}\lim_{x \to +\infty} \frac{e^{x}}{e^{x} + \frac{1}{3}} \= \frac{24}{3}\lim_{x \to +\infty} \frac{1}{1 + \frac{1}{3e^{x}}} = 8

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

stoic imp
#

,, \lim_{x \to -\infty} \frac{24e^x}{3e^x + 1}

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

tulip ore
#

are you sure the question is to find the range of that function

#

right now all youre calculating are limits

#

you dont use limits to find the rnage

stoic imp
#

well

#

its the image, not range

tulip ore
#

from?

#

R?

stoic imp
#

idk the translation omg

#

can u google translate real quick=?

meager trellis
#

yeah that sounds like they're probably asking for the range

tulip ore
#

the english word image and range are interchangeable

stoic imp
#

okay

tulip ore
#

when you get to higher portions where the preimage or domain no longer mean the same thing, a distinction appears

stoic imp
#

okay

tulip ore
#

you can start at the range of e^x being (0, inf) and build up the function

#

that can be used if you only have one e^x in the function

stoic imp
#

0, inf?

#

how so?

#

can you elaborate in detail

tulip ore
#

the range of $y=e^x$ is $(0,\infty)$

meager trellis
#

not "0, inf", (0, inf)

stoic imp
#

why doe

jolly parrotBOT
stoic imp
#

,w range e^x

tulip ore
#

the (0, inf) is interval notation

jolly parrotBOT
meager trellis
#

the open interval, "all numbers strictly greater than 0" ("up to infinity" meaning no upper bound)

tulip ore
#

it is short for "0 < something < infinity"

stoic imp
#

but why

#

is only positive

#

i dont get it

tulip ore
#

can you raise e to a power

#

and get 0?

#

remember youre only working with real numbers

stoic imp
#

never no

tulip ore
#

can you raise e to a power

stoic imp
#

u cannot

tulip ore
#

and get a negative number?

stoic imp
#

okay I feel u

#

but

tulip ore
#

that is what range means

#

remember youre only working with real numbers

#

ln(-1) is ambiguous and is also not real

#

please pay attention

#

are you paying attention right now?

#

I need a yes

stoic imp
#

yes

tulip ore
#

the range of e^x is believably (0, inf), right?

stoic imp
#

sure

tulip ore
#

can you elaborate on whats holding you back from completely believing it

stoic imp
#

nothing

tulip ore
#

using "sure" instead of "yes" is usually meant to mean "I see that you want me to believe that" and doesnt actually show whether you understand or not

stoic imp
#

yes

#

y

tulip ore
#

yea dw

stoic imp
#

so what?

tulip ore
#

you can start at the range of e^x being (0, inf) and build up the function
that can be used if you only have one e^x in the function

#

right now theres two e^xs so its not immediately useful

#

but theres an easy way to reduce the number of e^xs there are in the function to one

stoic imp
#

,, f(x) = \frac{24e^x}{3e^x + 1}

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

stoic imp
#

well

#

$\frac{24e^x}{3e^x + 1} = \frac{24e^x}{3e^x + 1} + \frac{24e^x}{3e^x + 1}$ is this legal

tulip ore
#

is $\frac32=\frac31+\frac31$?

jolly parrotBOT
stoic imp
#

nope

tulip ore
#

then no its not legal

stoic imp
#

I messed up

tulip ore
#

if you want to split the fraction into something that cancels out nicely, you need to consider the entire denominator

#

see if you can get some version of a 3e^x + 1 in the numerator

#

right now it says 24e^x

stoic imp
#

omg

#

8(3e^x + 1) = 24e^x - 8

tulip ore
#

8(3e^x + 1) - 8 = 24e^x you mean

stoic imp
#

yeah that

#

sirry

tulip ore
#

its alr

stoic imp
#

now what

tulip ore
#

put that in the numeraotr

stoic imp
#

okay

tulip ore
#

then see if you can simplify f

stoic imp
#

,, \frac{8(3e^x + 1)-8}{3e^x + 1}

tulip ore
#

no not like that

#

youre forgetting the - 8 again

stoic imp
#

mb

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

tulip ore
#

yea

#

try simplifying f

stoic imp
#

okay

#

,, \frac{8(3e^x + 1)-8}{3e^x + 1}=8-\frac{8}{3e^x + 1}

jolly parrotBOT
#

938c2cc0dcc05f2b68c4287040cfcf71

tulip ore
#

thats correct

stoic imp
#

😎

tulip ore
#

now with one e^x, you can start from "the range of e^x is (0, inf)" and apply each calculation that f does to the range

#

for example 1 + e^x's range is (1, inf)

stoic imp
#

sure

#

,w range 8 - 8/(3e^x + 1)

jolly parrotBOT
tulip ore
#

bruh

stoic imp
#

(0,8)

#

but for y to be 0

#

3e^x + 1 has to be 1

#

but e^x is never negative

tulip ore
#

did you figure it out yourself or did you just use wolfram alpha to give me that answer

stoic imp
#

nono, I still dont understand it

#

I am gathering info

tulip ore
#

I told you the general method

#

you are not using it

#

do you want a different one

stoic imp
#

wdym different one? I usually do this shit using limits ngl

tulip ore
#

you gotta ask when you dont understand something

#

forget this

#

we're doing something completely different

#

you arent even looking at what I suggested to you

stoic imp
#

I mean

#

you said

#

e^x range is 0,inf

#
  • 1
#

1, inf

#

then multiplied by 8

#

8, inf

#

then?

tulip ore
#

first off

#

this is your function

#

you are not finding the range of 8 (e^x + 1)

#

second off

#

not a single word abotu this until after I look like Im dropping the idea entirely

stoic imp
#

sorry

tulip ore
#

surely its not an exclusively english idea to you to say when you do something

#

you believe this?

stoic imp
#

I am not sure what ur asking tbh, my english is bad

#

I believe what ?

tulip ore
#

this is your function

#

what is the range of 3e^x

stoic imp
#

0,uif

tulip ore
#

what is the range of 3e^x + 1

stoic imp
#

1,inf

tulip ore
#

what is the range of 8 / (3e^x + 1)

stoic imp
#

ohh

#

3e^x + 1 > 0

tulip ore
#

no

#

already youre doing something bizarre

#

why not > 1?

stoic imp
#

mb

#

why > 1 doe

tulip ore
#

you just said the range of 3e^x + 1 is (1, inf)

#

that means 3e^x + 1 > 1

stoic imp
#

💯

tulip ore
#

@stoic imp are you stuck

stoic imp
#

lowkey yeah

tulip ore
#

you didnt say anything

#

care to explain?

stoic imp
#

okay

#

how to get the range of rhe fraction

tulip ore
#

youre doing a good job explaining so far

#

please keep this up ok?

stoic imp
#

okay

tulip ore
#

say you have a number between 2 and 4

#

and you take its reciprocal

#

that number then is between 1/4 and 1/2, right?

stoic imp
#

okay but what does reciprocal even mean

#

you flip it

tulip ore
#

reciprocal is an english term for doing 1 / (something) or (something)^-1

#

flipping is ambiguous and should not be used

stoic imp
#

okay

#

0,25

#

0,5

tulip ore
#

thats not ideal

#

you dont need to convert 1/4 and 1/2 to decimals to understand what Im going to say

stoic imp
#

okay

tulip ore
#

now say you have a number that is at least 127

stoic imp
#

is just the ordering

#

that scared me a little bit

tulip ore
#

1/4 and 1/2 are numbers you know

#

are you familiar with them

stoic imp
#

1/2 and 1/4

#

yes

tulip ore
#

wait you are?

#

what about 1/127?

stoic imp
#

0.5 and 0.25

#

,calc 1/127

tulip ore
#

no not like that

jolly parrotBOT
#

Result:

0.0078740157480315
tulip ore
#

no

#

Im asking if youre familiar with the fractions 1/2 and 1/4

#

instead of reading them as a weird way to write a decimal

stoic imp
#

okay

tulip ore
#

this is taking too long, you can ignore that question

#

say you have a number thats 127 or higher

#

and you take its reciprocal

#

the reciprocal is between which two numbers?

stoic imp
#

can i respond with unsure

tulip ore
#

say you have a number thats between 127 and 131

#

and you take its reciprocal

#

the reciprocal is between which two numbers?

stoic imp
#

127^-1 and 131^-1

tulip ore
#

now if numbers are bigger

#

reciprocals are smaller

#

right?

stoic imp
#

y

tulip ore
#

I gotta break it to you but "y" is ambiguously "yes" or "why"

stoic imp
#

yess what then?

#

so what

tulip ore
#

think about its reciprocal

#

its positive, rightg

stoic imp
#

yeah

#

tulip ore
#

its also below 1/127, right

stoic imp
#

+inf, 1/127

tulip ore
#

now you gotta be careful with what youre saying there

#

can you repeat the two numbers the reciprocal is between?

somber mason
#

how did you guys get to this point

tulip ore
#

this was supposed to be the easy way out

#

but you gotta build up the basics first

stoic imp
#

127^-1 and 131^-1

tulip ore
#

that means it can go lower than 131^-1

stoic imp
#

okay

tulip ore
#

it can go lower than any positive number

#

but it cant go lower than 0

#

right?

stoic imp
#

right

tulip ore
#

it cant be 0 either, right?

stoic imp
#

right

tulip ore
#

so knowing 127 < number,

#

what would that mean for the reciprocal?

stoic imp
#

(0, 1/127]

tulip ore
#

0 < reciprocal < 1/127

stoic imp
#

now ?

tulip ore
#

writing $f(x)$ as $8-8\cdot\frac1{3e^x+1}$,

jolly parrotBOT
tulip ore
#

and knowing the range of 3e^x + 1 is (1, inf),

#

what is the range of 1 / (3e^x + 1)?

stoic imp
#

(0, 1]

tulip ore
#

thats correct

#

whats the range of 8 * 1 / (3e^x + 1)

stoic imp
#

(0,8]

tulip ore
#

wait

tulip ore
tulip ore
tulip ore
#

so 1 is left out

#

whoops

#

so the range of 1 / (3e^x + 1) is (0, 1)

stoic imp
#

(0,8)

tulip ore
#

yea

#

then whats the range of 8 - 8 * 1 / (3e^x + 1)

stoic imp
#

(0,1)

tulip ore
#

...whats the range of 8 * 1 / (3e^x + 1)

stoic imp
#

(0,8)

tulip ore
#

so whats the range of 8 - 8 * 1 / (3e^x + 1)

stoic imp
#

unsure

tulip ore
#

if you have a number from 0 to 8

#

and you subtract it from 8

#

what numbers would it be between

stoic imp
#

-8,0

tulip ore
#

I didnt say to subtract 8 from it

#

subtract it FROM 8

stoic imp
#

mb

tulip ore
#

I said **8 - **

#

so if you have 8 - a number,

#

what numbers would it be between

stoic imp
#

8 to 0

tulip ore
#

yes

#

so (0, 8)

#

right?

stoic imp
#

sure

tulip ore
#

the range of 8 * 1 / (3e^x + 1) is (0, 8)

#

so whats the range of **8 - **8 * 1 / (3e^x + 1)

stoic imp
#

8 to 0

tulip ore
#

yes

#

so (0, 8)

#

right?

stoic imp
#

mhmmkay

#

i usually do it with limits doe

tulip ore
#

how would that work

stoic imp
#

or finding the domain of the inverse

tulip ore
#

neither this or the other one reliably works

stoic imp
#

reliably

#

no but

#

usually its better to know where the asymptotes are to find the range quicker no?

tulip ore
#

would it work for 1 / (1 + x^2)?

stoic imp
#

by doing a sketch of the function

tulip ore
#

you dont define functions by their asymptotes

stoic imp
#

I was referring to finding the range

tulip ore
#

what?

#

how does that go against what I said? youre implying I didnt know you were doing that?

stoic imp
#

no

#

its just

#

nothing

tulip ore
stoic imp
#

well

tulip ore
#

its not necesary to know about the asymptotes to find range

tulip ore
#

so in terms of that its not very good confirmation

#

the asymptote can at least guarantee that the range should include a (asymptote or asymptote) in at least one interval

stoic imp
#

asymptote or asymptote

#

okay

tulip ore
#

you should repeat the ()s

stoic imp
#

but

#

then asymptotes don’t work for finding image?

#

wdym

tulip ore
#

you found that as x -> inf, f(x) -> 8

#

this tells you that the image should have a 8) or a (8 somewhere

stoic imp
#

yeah

tulip ore
#

the image of f(x) is (0, 8) which we found without ever caring about the asymptotes

stoic imp
#

okay

tulip ore
#

you can see there the 8) as suggested by the asymptotes

stoic imp
#

but that is only vertical asymptote we still need to find horizontal and oblique asymptotes before we find range

tulip ore
#

x -> inf is not a vertical asymptote

stoic imp
#

that is horizontal mb

tulip ore
#

now you do have something neat if you look for vertical asymptotes

#

if you have a limit that -> inf or -> -inf,

#

x -> something, f(x) -> inf would confirm a inf)

stoic imp
#

sure

tulip ore
#

x -> something, f(x) -> -inf would confirm a (-inf

stoic imp
#

okay

#

sure

#

what about oblique asymptotes

#

let me bring the formula

tulip ore
#

that sounds like a lot of work for asymptotes that we ultimately dont need

#

if you do find an oblique asymptote, it still fits what I said about vertical asymptotes

#

alr I gtg

pearl pondBOT
#

@stoic imp Has your question been resolved?

pearl pondBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

sharp smelt
#

what am I doing wrong here

pearl pondBOT
main oxide
verbal whale
verbal whale
sharp smelt
#

ooh

#

got it

#

yeah, silly mistake on my end

#

thanks!

#

,clos

#

.close

pearl pondBOT
#
Channel closed

Closed by @sharp smelt

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

edgy otter
#

How do I simplify this/ what do I do next?

ivory swallow
#

first of all you can simplify f(t)

#

(6t+18)/(t+7) = [6 (t+3) ] / (t+7) = (6(t+7) - 42 + 18) / (t+7) = (6(t+7) - 24)/(t+7) = 6 - 24/(t+7)

edgy otter
#

Does this work?

stoic pecan
#

i assume yes since theres lims

edgy otter
#

I think I have it in my notes

stoic pecan
#

wait

#

i have an apropiate image

edgy otter
#

LMAO

stoic pecan
#

oh wait yeah you can simplify it

#

thats probadly easier than this

#

but this should work just fine

solid pier
edgy otter
#

so what do i do 😭

kind rampart
stoic pecan
edgy otter
stoic pecan
#

oh idk what you did

edgy otter
stoic pecan
#

i meant quotient rule or differntiating that guys simplified form

edgy otter
# stoic pecan

I should understand this but I'm also bad at minecraft

#

I like farming

stoic pecan
#

thats fine

stoic pecan
edgy otter
#

gave them a common demoninator?

#

i think

stoic pecan
#

am i misunderstanding the question or are you not supposed to just differntiate it

#

and thats it

edgy otter
#

i don't get how to do that 😭

#

I'm so confused

stoic pecan
#

uh

#

like

#

f(t) = 5x^2

#

f'(t)=10x

#

like that?

#

whats this btw

#

is a just a value

#

or something else

edgy otter
#

derivative?

#

i think

#

im dying here

stoic pecan
#

yes

#

okay so you jsut derive it

#

lets do this guys method first

edgy otter
#

im doomed

stoic pecan
#

6-24/(t+7)

#

do you know how to derivate 6

#

lets start there

edgy otter
#

all i know is dy/dx

stoic pecan
#

yeah

#

do you not know like derivation basics

#

if not this is prob impossible

edgy otter
#

😭 im so screwed for my exam on saturday

stoic pecan
#

you got time

#

go watch a video from organic chem or khan academy

#

its not that complicated

edgy otter
#

i'll go do that and be back in the morning

stoic pecan
#

alright

#

good luck

edgy otter
#

Could also be cause its like 3am for me

#

tyty

#

🫡

glacial sequoia
#

Writing it as
[ 6 - \f{24}{t + 7} ]
might make it easier for you

stoic pecan
#

nah she doesnt know like derivation of 6

#

its alr we all start without knowing it

jolly parrotBOT
glacial sequoia
edgy otter
#

I'll go watch some khan academy b4 i come back

#

ty guys for your help!!

#

.close

pearl pondBOT
#
Channel closed

Closed by @edgy otter

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

midnight haven
#

The reflection of the plane P1:2x−3y+4z−3=0, in the plane P2:x−y+z−3=0, is the plane ?

midnight haven
#

Status 1

#

A.4x−3y+2z−15=0
B)4x−2y+z−15=0
C)3x−2y+2z−15=0
D)None of these

pearl pondBOT
#

@midnight haven Has your question been resolved?

midnight haven
#

<@&286206848099549185>

midnight haven
#

Considered a random point on the plane 2x-3y+4z-3

#

(-2,-1,1)

#

found the image of the point wrt to the plane x-y+z-3=0

#

${-2+2sqrt3,-1-2sqrt3 ,1+2sqrt(3)}$

jolly parrotBOT
#

Cnidarian

midnight haven
#

so I choose D

#

i was wrong

#

This is what i did

#

2 min i will check

#

:p

#

i used the wrong formula

#

I always forget that the sqrt doesn't exist

#

thank you!

#

got it

#

.close

pearl pondBOT
#
Channel closed

Closed by @pseudo gulch

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

pulsar stump
#

is $k^m$ called "algerbric field"? and what does it equate to?

jolly parrotBOT
#

Ayanokoji

rustic gate
#

no you'd call it a vector space

#

in your picture the elements are being denoted with column vectors

sweet snow
rustic gate
#

its just what people call it

sweet snow
#

But a vector space is not just a set of vectors

#

It also needs a set of scalars and a binary operation

pulsar stump
rustic gate
#

K^m can be equipped with those operations in a natural way

rustic gate
pulsar stump
#

.close

pearl pondBOT
#
Channel closed

Closed by @pulsar stump

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

pulsar stump
rustic gate
#

(technically, you need to equip K^m with the vector space operations and then say that its a vector space but thats being pedantic)

pulsar stump
#

.close

pearl pondBOT
#
Channel closed

Closed by @pulsar stump

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

full tree
#

This seams to easy to be true <@&286206848099549185>

muted shale
#

!15m

pearl pondBOT
#

Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.

full tree
#

ok

#

.close

pearl pondBOT
#
Channel closed

Closed by @full tree

Use .reopen if this was a mistake.

muted shale
#

you can ask your question

#

just dont ping until after 15 minutes

full tree
#

ok

#

thx

#

I got it tho

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

raven spade
#

How do I proceed with this? All I got was simplifying the numerator to (x^3 + 1)(x^3 - 1)

brisk steeple
#

what is R?

rugged jolt
#

real numbers

brisk steeple
#

oky

light helm
#

consider: $x^6 - 1 = x^6 + 1 - 2$

jolly parrotBOT
#

ℝαμΩℕωⅤ

raven spade
#

hold on

raven spade
#

oh wait

#

i can try long division

glacial sequoia
#

You could also trig sub and repeatedly use 1 + tan^2 x = sec^2 x

rugged jolt
#

i had the sudden idea of doing [\frac{x^6}{1+x^2}-\frac{1}{1+x^2}] to get a -arctan term, but probably would lead to bad integration by parts.

jolly parrotBOT
glacial sequoia
#

It'll only take like 2 iterations

raven spade
glacial sequoia
#

Did you do the trig sub?

#

x = tan u

raven spade
#

oh wait

#

so would that be [tan^6(x) + 1 - 2]/tan^(x) + 1

light helm
#

with the route i suggested, you don't really need trig sub

glacial sequoia
#

You can try both

#

What Ramanov said is faster but less obvious if you're newer

light helm
#

if you want to do long division, just do it directly
the way i expressed it, a sum of two cubes identity can be applied to (x^6 + 1) which makes the division very simple

#

and an integral identity can be applied to the other fraction if you're allowed to use it
(or use x = tan(u) for that part)

raven spade
#

i'll try that out

#

thanks

raven spade
#

it's x^6 - 1 in the numerator of the question

light helm
#

you can rig it so that x^6 + 1 appears

#

as mentioned earlier

raven spade
#

i'm sorry if i'm sounding daft i'm half sleepy rn 😭

raven spade
pearl pondBOT
#

@raven spade Has your question been resolved?

pearl pondBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

sharp smelt
#

could I have a hint?

pearl pondBOT
sharp smelt
#

I think the last bit is wrong

#

maybe use something similar to the sandwhich theorm ?

#

or a trig substitution?

#

just a hint please

autumn trellis
#

write $(1+a)^{n+1}=(1+a)(1+a)^{n}$

jolly parrotBOT
#

quickdoom

sharp smelt
#

mhm

autumn fossil
#

What does that even mean?

sharp smelt
#

nothing, was just jotting down my thoughts

autumn fossil
#

ohk

sharp smelt
#

could I use a sub for $a\in [-1,0)$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

sharp smelt
#

like $a =cos(2u)$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn trellis
sharp smelt
#

I don't see how writing it like that helps

#

sorry

autumn fossil
#

You already know something about (1+a)^n...

sharp smelt
#

it's more than $na+1$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn fossil
#

and so you can conclude something about (1+a)*(1+a)^n

#

correct

#

so what can you conclude about (1+a) * (1+a)^n?

#

(which is equivalent to (1+a)^(n+1))

sharp smelt
#

it's more than $(1+a)(1+na)$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

#

quickdoom

autumn trellis
#

Usually with inductipn proofs you xan just follow the algebra

autumn fossil
#

oh there is just one mistake

sharp smelt
#

right

autumn fossil
#

expand and see what you get

sharp smelt
#

$(1+a)(1+(n+1)a)$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn fossil
#

hmm

#

that doesnt look like (1+a)(1+na)

autumn trellis
autumn fossil
autumn fossil
#

a(1+n)

autumn trellis
#

That is correct though

jolly parrotBOT
#

quickdoom

rustic gate
#

texsp fail

autumn trellis
autumn fossil
#

uh

#

what kind of algebra?

autumn trellis
#

Read the spoiler

autumn fossil
#

(1+a)^3 = (1+a)^2 + a(1+a)?

autumn trellis
#

Yeah?

autumn fossil
#

we can clearly see that its not true, just by comparing the degrees. Or am I missing something?

autumn trellis
#

Forgive me

#

Im quite stupid

autumn fossil
#

(1+a)^3 = (1+a) * (1+a)^2

#

thats the right one

rustic gate
#

i think you applied the induction hypothesis halfway there

autumn fossil
#

now you can just expand that

sharp smelt
#

ok,, so that gives me $1+na+a+na^2$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn fossil
#

okay, good

#

now you need that to be greater than (or equal to) 1 + (n+1)a

#

so think about how would you verify that

autumn trellis
autumn fossil
#

@sharp smelt Any progress? You are not far

sharp smelt
#

not really

#

one minute

#

I feel that subbing a=cos(2u) may be easier here

autumn fossil
#

no, dont overthink it

#

all you need to prove is

1 + na + a + na^2 >= 1 + (n+1)a

sharp smelt
#

right

autumn fossil
#

treat it like those inequations where you are solving for x

#

just manipulate it smh

sharp smelt
#

I can cancel outt terms

autumn fossil
#

indeed

sharp smelt
#

so this gives me $na^2 \geq0$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn fossil
#

correct

#

when is product of 2 things greater than 0?

#

(or equal)

sharp smelt
#

which is when both are positive or negative

autumn fossil
#

yeah

#

or one of them is 0

#

that would work too

#

can you determine their signs?

sharp smelt
#

n>0

autumn fossil
#

correct

sharp smelt
#

as we're working on N

#

as is a^2

autumn fossil
#

a^2, not a

sharp smelt
#

so this is always true

autumn fossil
#

yeah

#

squares are non-negative

sharp smelt
#

got it

#

tysm!

autumn fossil
#

np

#

but wait a moment

#

it would be good if you wrote it in one line

sharp smelt
#

ok, let me try

#

$(1+a)(1+a)^n \geq (1+a)(1+an) \implies 1+na+a+na^2\geq na+a \implies na^2>0$

jolly parrotBOT
#

ƒ(Why am. I here)=I don't Know

autumn trellis
#

Write = instead of =>

#

And, that series of implications doesnt lead us to what we want

sharp smelt
#

it does, doesn't it?

autumn trellis
#

We want to show that (1+a)^{n+1} \geq 1+(n+1)a

sharp smelt
#

yes

autumn fossil
#

the thought process behind that was correct, but now you just need to transform it to a proof

#

which should ideally look like this:

(1+a)^(n+1) >= ... >= ... >= ... >= 1 + (n+1)a

sharp smelt
#

wait, what

autumn fossil
#

the part where I told you to "solve" the inequation 1 + na + a + na^2 >= 1 + (n+1)a was mainly supposed to guide you towards the right manipulation

sharp smelt
#

yeah

#

but isn't that enough?

autumn fossil
#

It is, but its not that elegant

#

the proof wouldnt be that readable

#

You already had (1+a)^(n+1) = (1+a) * (1+a)^n >= (1+a) * (1 + na) = 1 + a + na + na^2

#

now you just need to continue this and reach >= 1 + (n+1)a

#

Which term was the only one that didnt cancel when you did the manipulation?

sharp smelt
#

uh

#

one minute

#

I'm lost sorry, I'll try this again tomorrow

#

is that fine?

#

@autumn fossil

autumn fossil
#

I'll just show you im sure youll understand

#

if you dont mind

#

its really quick

sharp smelt
#

ok

autumn fossil
#

(1+a)^(n+1) = (1+a) * (1+a)^n >= (1+a) * (1 + na) = 1 + a + na + na^2 >= 1 + a + na = 1 + a(n+1)

#

and done

#

the key observaton was that most of the terms cancel, except for na^2

#

so we needed to remove that one

sharp smelt
#

yeah, makes sense

autumn fossil
#

and then its equal

rustic gate
#

,align[2\textwidth] (1 + a)^{n + 1} & = (1 + a)\2b{(1 + a)^n} \ & \ge (1 + a)\2b{(1 + na)} \ & = 1+ a + na + \2o{na^2} \ & \2o{\ge} 1 + a + na \ & = 1 + (n + 1)a

sharp smelt
#

hmm, yeah

#

makes sense

jolly parrotBOT
sharp smelt
#

uh, I really have to go now, sorry. Thanks for all the help

#

can I close this?

rustic gate
#

yeah you can go

autumn fossil
#

sure

rustic gate
#

the non tex'd math was just making my eyes bleed kekehands

sharp smelt
#

sorry, and thanks a lot for the help

#

.close

pearl pondBOT
#
Channel closed

Closed by @sharp smelt

Use .reopen if this was a mistake.

autumn fossil
#

I need to start using tex again

#

ill start practising

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

inland ivy
#

$$\text{Prove that} \frac{\int_0^{\frac{\pi}{2}}\log(\sin x)dx}{\int_{-\frac{\pi}{4}}^{\frac{\pi}{4}}\log(\sin x+\cos x)dx}=2$$

inland ivy
#

ugh that looks horrible

jolly parrotBOT
#

kheerii

inland ivy
#

sure I guess that kinda works

#

how I did this was write the bottom integral as $I_2=\int_{-\frac{\pi}{4}}^{\frac{\pi}{4}}\log\left(\sqrt{2}\sin\left(x+\frac{\pi}{4}\right)\right)dx=\frac{\pi}{4}\log 2+\int_0^{\frac{\pi}{2}}\log(\sin x)dx =\frac{\pi}{4}\log 2+I_1$

jolly parrotBOT
#

kheerii

inland ivy
#

From here, I solved for $I_1$ to get $I_1=-\frac{\pi}{2}\log 2$ which gives us the result combined with the other equation we got, $I_2=\frac{\pi}{4}\log 2+I_1$

jolly parrotBOT
#

kheerii

inland ivy
#

can anyone think of a way to solve this without explicitly solving for I_1?

glacial sequoia
#

yes

#

but from the beginning

inland ivy
#

what's that

glacial sequoia
#

for the bottom integral sub x --> -x and add it back to itself

inland ivy
#

ohh cos2x

glacial sequoia
#

you get cos 2x inside the log, then sub 2x

inland ivy
#

gotcha

glacial sequoia
#

yes

inland ivy
#

cool

#

that was way easier\

#

than I thought

#

bruh

#

thanks neon

#

.close

pearl pondBOT
#
Channel closed

Closed by @inland ivy

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

oak falcon
#

How would you slolve this?

pearl pondBOT
brisk steeple
#

use the binomial theorem to expand (1+2/3)^-4

oak falcon
#

whats that?

#

.close

brisk steeple
#

nvm.

pearl pondBOT
#
Channel closed

Closed by @oak falcon

Use .reopen if this was a mistake.

brisk steeple
#

first convert it into a improper fraction

oak falcon
#

.reopen

pearl pondBOT
#

oak falcon
#

so 5/3

brisk steeple
#

yeah. now solve

oak falcon
#

oh 3/5

worthy lance
#

That’d be if it were -1 not -4

brisk steeple
#

yeah

oak falcon
#

3/5 ^4?

brisk steeple
#

yup

oak falcon
#

ty

brisk steeple
#

yw

oak falcon
#

.close

pearl pondBOT
#
Channel closed

Closed by @oak falcon

Use .reopen if this was a mistake.

brisk steeple
#

,w 0.8^4

jolly parrotBOT
worthy lance
brisk steeple
#

yes.

#

,w 0.6^4

jolly parrotBOT
pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

split lark
#

pls help is this solution correct?

pearl pondBOT
warm current
#

Looks good

split lark
#

ok thx

#

.close

pearl pondBOT
#
Channel closed

Closed by @split lark

Use .reopen if this was a mistake.

pearl pondBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

jolly nova
#

How does one solve
$$4x^3+30x^2+66x+40 = 0$$
I got this as one of the last steps in the assignment, and I don't know how to continue from here. The answers in my book didn't really help me as they fastforwarded straight to the answer.

jolly parrotBOT
#

ReaMart

jolly nova
#

as far as I know this is a cubic/third degree equation. This is what the answer says:

quiet tendon
#

there technically is an explicit cubic formula but that's kind of overkill

#

if you can find a single solution you can reduce it to a quadratic

jolly nova
#

hmm yes

quiet tendon
#

rational root theorem helps you check for any rational roots here

#

which is always a good way to quickly find a root to reduce this

jolly nova
#

btw the function that is equal to 0 is called f(x)

and my book says
$$f(x) = 0 \text{ gives } x=-1 \vee x=-2\frac{1}{2} \vee x=-4$$

jolly parrotBOT
#

ReaMart

quiet tendon
#

so is the problem coming up with those solutions?

jolly nova
#

yeah

quiet tendon
#

do you know what rational root theorem is?

jolly nova
#

let me translate it real quick

quiet tendon
#

okay

jolly nova
#

no I don't know it

quiet tendon
#

if you have a polynomial with integer coefficients

#

then there's a finite possible set of rational roots

#

of that polynomail

#

and you can find out all possible candidates for the rational roots using this theorem

#

take all possible factors of the constant term and divide them by all possible factors of the coefficient of the term of highest degree

#

so for example, you can firstly rewrite your equation as 2x^3 + 15x^2 + 33x + 20 = 0

jolly nova
#

yeah

quiet tendon
#

if you divide by 2 again you no longer ahve integer coefficents