#help-38

1 messages ¡ Page 213 of 1

burnt mulch
#

So you want to get from f'(x/2) to f'(x) somehow

#

And this is the most natural way to do it

vocal cobalt
#

what do i do now?

burnt mulch
#

b/c atm, you only have info about the arc length of f, and hence about the integral of sqrt(1+(f'(x))^2)

#

What do you have about arc length in the question rn?

vocal cobalt
#

the final answer should be of numbers

vocal cobalt
#

from the expression i got

burnt mulch
#

????

#

I'm asking you to read the question

#

and tell me what it tells you about the arc length of the graph of f

vocal cobalt
#

0 to 5 is 11 and 5 to 10 is 18

burnt mulch
#

mhm

vocal cobalt
#

so i just do that?

burnt mulch
#

what exactly are you doing with those numbers

vocal cobalt
#

since its like in the arc length formula style i just get the arc length thats given? but i dont get what length im getting with 0

burnt mulch
#

You want to find $2 \int^{10}_{0} \sqrt{1+(f'(x))^2} \dd{x}$.

solid kilnBOT
#

Civil Service Pigeon

burnt mulch
#

Currently, the arc length information they gave you is in words.

burnt mulch
#

this way you're saying "ok I have these integrals, and I need to find this integral"

vocal cobalt
#

int 0 to 5 sqrt (1+(f'(x))^2) dx? like this?

burnt mulch
#

sure

vocal cobalt
#

int 5 to 10 sqrt (1+(f'(x))^2) dx

#

how is this gonna give me answer?

#

i combine it?

burnt mulch
#

try it out

vocal cobalt
#

int 0 to 5 sqrt (1+(f'(x))^2) dx + int 5 to 10 sqrt (1+(f'(x))^2) dx = int 0 to 10 of sqrt (1+(f'(x))^2) dx

#

and i multiply 2?

burnt mulch
#

yes

vocal cobalt
#

ok got it

#

thanks for helping 😀

#

.close

trim joltBOT
#
Channel closed

Closed by @vocal cobalt

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.

tender flame
#

should i rearrange for x because its revolved about y-axis?

trim joltBOT
#

@tender flame Has your question been resolved?

trim joltBOT
# tender flame should i rearrange for x because its revolved about y-axis?
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.

trim joltBOT
#
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.

trim joltBOT
odd tapir
#

is this wrong?

#

because don't they both approach 0

split chasm
#

yeh, its wrong

trim joltBOT
#

@odd tapir Has your question been resolved?

trim joltBOT
#
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.

drifting reef
#

me

trim joltBOT
drifting reef
#

23x3

#

how do you do 23x3

solid sundial
#

use a calc

#

or so 20x3 + 3x3

drifting reef
#

ok

mortal kestrel
worldly wing
#

too hard

mortal kestrel
#

Frfr

stuck plover
#

Use column addition

drifting reef
#

ok

stuck plover
#
2 3
2 3
---
? ?
---```
drifting reef
#

😮

#

i see

#

.close

trim joltBOT
#
Channel closed

Closed by @drifting reef

Use .reopen if this was a mistake.

trim joltBOT
#
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.

silent kiln
trim joltBOT
silent kiln
#

Would it be incorrect to say $n^3$ because there could be $f(n) \geq n^3$?

solid kilnBOT
#

allarkvarkk

queen beacon
silent kiln
solid kilnBOT
#

allarkvarkk

silent kiln
queen beacon
#

Well, what does the master theorem give you

#

What’s the statement and does it apply, first off

silent kiln
#

wait i got it nvm

#

ty for the help

#

:)

#

.close

trim joltBOT
#
Channel closed

Closed by @silent kiln

Use .reopen if this was a mistake.

queen beacon
#

So real

trim joltBOT
#
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.

verbal linden
#

i'm trying to calculate the probability of a portfolio value within a certain Z-score range at a certain time t, or alternatively calculate a probability density function at time t. here is an example scenario:

say i have $100 principal to invest in a portfolio. the portfolio's expected annual return is 8% with a standard deviation of 15%. i will be withdrawing $7 from the portfolio every year.

Now, for every year, i would like to know the PDF of the total portfolio value at that time. or for simplicity, i would like to know the values at Z=1 and Z=-1.

verbal linden
#

finding the mean (Z=0) at any time, is simple even with the fixed withdrawal rate. but finding any other value for Z becomes non-trivial, because of the fixed withdrawal rate (not being a percentage of the total)..

trim joltBOT
#

@verbal linden Has your question been resolved?

trim joltBOT
#

@verbal linden Has your question been resolved?

trim joltBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

verbal linden
#

.reopen

trim joltBOT
#

✅

trim joltBOT
#

@verbal linden Has your question been resolved?

trim joltBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

verbal linden
#

.reopen

trim joltBOT
#

✅

verbal linden
#

thought i should mention, i am trying to get a closed-form mathematic solution, not monte-carlo simulation.

zinc raptor
#

you should be able to set up a recurrence for the variance in the same way you solved for the mean

#

i can't guarantee it will result in anything nice

#

your random variable after n years is a sum of products of up to n independent gaussians, which i don't think has a nice pdf

trim joltBOT
#

@verbal linden Has your question been resolved?

verbal linden
verbal linden
#

P = principal (100)
W = fixed annual withdrawals (7)
R = exopected rate of return (0.08)

#

adding volatility into the first term (the principal amount) is easy:

#

Z = Z-score
V = volatility (0.15)

#

but i still need to account for volaility in the second term (the withdrawals).

#

because withdrawals don't simply apply in a deterministic way like that. withdrawals continuously reduce the size of the effective principal amount that would otherwise be subject to volatility..

trim joltBOT
#

@verbal linden Has your question been resolved?

verbal linden
#

when i started trying to figure this out, i thought it would be a simple problem, but it might in fact be impossible to do..?

trim joltBOT
#

@verbal linden Has your question been resolved?

simple haven
#

It's actually pretty difficult because you're withdrawing a fixed value, rather than a percentage.

verbal linden
#

if i was withdrawing a percentage. then it could just simply be factored in at the same place as the expected return (R) i'm assuming?

simple haven
#

Hmm... Perhaps this counts as a semimartingale

#

Yeah, this counts pretty sure

verbal linden
#

if withdrawals are fixed nominal values, then it's a random walk with a positive drift (in percentage, so compounded) combined with a linear negative amount over time.

#

if withdrawals are percentages, then it's a random walk with a positive or negative drift (depending on the value after R - W), so yes much simpler.

verbal linden
simple haven
#

In probability theory, a real valued stochastic process X is called a semimartingale if it can be decomposed as the sum of a local martingale and a cĂ dlĂ g adapted finite-variation process. Semimartingales are "good integrators", forming the largest class of processes with respect to which the ItĂ´ integral and the Stratonovich integral can be ...

verbal linden
#

ngl, most of that went over my head. i'm kind of a math pleb.

simple haven
#

It's ok, this is not math I'm super familiar with either.

verbal linden
#

but seems like they say brownian motion is a semimartingale. and i think this process is brownian motion; volatility in finance can be treated like that.

#

still unsure how exactly to combine a fixed linear rate of depletion to an otherwise typical brownian motion.

simple haven
#

That's part of the cĂ dlĂ g process

verbal linden
#

hmm, does cadlag work for something that is continuous? or only in the case of withdrawals being discrete events happening once per year. maybe it wasn't clear from my explanation attempt, but the withdrawal rate is $7/year but it happens continuously, if that makes sense.

#

$0.01917808219 /day for example

#

the timeframe doesn't matter, just that the total withdrawn is a linear thing over time.

#

the rate of withdrawal is independent from the portfolio value, but it is still continuous.

simple haven
#

Sorry, I stepped away for a moment

#

I thought you were modeling a discrete thing, but continuous makes it substantially easier actually

#

But yeah, changing it to continuous still is cĂ dlĂ g

verbal linden
#

ok, thanks. well i have some reading to do on cadlag!

trim joltBOT
#

@verbal linden Has your question been resolved?

onyx forge
trim joltBOT
#
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.

round minnow
trim joltBOT
round minnow
#

how to simplify this?

#

I've learned basic derivative rules and the hardest part is simplifying by far

vapid grove
#

rewrite roots as exponents if you need to

round minnow
#

alr bet lemme try

trim joltBOT
#

@round minnow Has your question been resolved?

#
Channel closed

Closed by @round minnow

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.

crimson halo
#

Can someone help me idk know what its asking me to do

crimson halo
#

I quite litteraly dont understand what it expects me to do

dapper swift
empty orchid
solid kilnBOT
dapper swift
#

yeah you save a step by doing that

crimson halo
#

Whats “parent fubction” even mean?

empty orchid
#

The function that was “originally there”.

#

i.e., the most basic form of the transformed function.

crimson halo
#

Its this vocabulary its stupid to me

#

Whats it mean by transforming the given the graph of the parent function

empty orchid
#

So if I were to, say, consider $g(x)=\frac12(x-5)^2+4$, and $f(x)=x^2$, then $\frac12f

solid kilnBOT
#

;(
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

crimson halo
#

I dont get ot whats it mean by transforming

crimson halo
#

Wait so all its asking is what transforms the given line to be the line that the equation goves?

dapper swift
#

but yes

#

so it's like a little game: each step, you replace or add something to y = x^2 to get it closer

#

the trick is you only need two steps

the first step is $y = x^2 \mapsto y = -\frac{1}{16} x^2$

solid kilnBOT
crimson halo
#

Im fed up dude my math teacher assigns us work over spring break

dapper swift
#

I'm not counting the minus as an extra step btw, should be pretty obvious what that does

dapper swift
#

I thought you already had yours lmao

#

fuck I have spring break only after next week, oh well

crimson halo
#

Nope ive had it with math every day i do it toll 10 pm and now i have to do it over the one fucking week i have to myself

dapper swift
#

noooooooooooooo

dapper swift
crimson halo
#

Idk

dapper swift
#

it's to do with the full moon actually

#

so that means it's lunacy (ba-dum-tss)

crimson halo
#

Ive had it bro two years ahead of my whole school and i have to do those

dapper swift
crimson halo
#

I cant say bruh

#

Wayy to many people on this server

#

Old enough tho dont worry

#

I need help on this i needa graph these

#

The second one doesnt make sense

#

Is the negative 1 applied to x or is it just negative 1

crimson halo
dapper swift
#

so that would be just the point (x, y) = (-2, -1)

crimson halo
#

How so

dapper swift
#

cause the piecewise domain there is only one x value

#

x = -2

#

usually it's a horizontal line, correct

crimson halo
#

I thought the left side is the equation and the right side tells you the limits

dapper swift
#

that's a single point

crimson halo
#

Ohhhh and the right side can tell you snything?

dapper swift
#

so if the domain is an inequality, which it usually is

#

you'd sketch that function between those x values

dapper swift
crimson halo
#

But this osnt an inequality so what is ot?

dapper swift
#

you have 1 value of x and 1 value of y

#

so a filled-in circle on your graph

crimson halo
#

But if its x=-2 how can it be -2,-1 if the -1 is the y intercept

dapper swift
#

you're thinking about it as a line which you shouldn't be

crimson halo
#

Im confused i thought the left side was the equation

dapper swift
#

yes

crimson halo
#

Ye so if its equation the only thing there is the y intercept

#

@dapper swift

trim joltBOT
#

@crimson halo Has your question been resolved?

dapper swift
#

.。。。。。。

#

idk what to say anymore

crimson halo
#

bruh pls i dont understand if the -1 is the y intercept and x is -2 how can it be -2,-1 if the negative one is the y intercept?

dapper swift
#

x = -2 and y = -1

crimson halo
#

but i thought the left side is an equation and the reg number is the y intercept?

dapper swift
#

not anymore

crimson halo
#

so in that its not an eqution?

dapper swift
#

yeah it's a point

crimson halo
#

ohhhh i understand it now

#

so f(x) just think of it as y

#

so y=-1

dapper swift
crimson halo
#

I only got that cus i asked gauth😭

trim joltBOT
#

@crimson halo Has your question been resolved?

#
Channel closed

Closed by @crimson halo

Use .reopen if this was a mistake.

crimson halo
trim joltBOT
#
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.

narrow jewel
#

hello im trying to prove that this is true
i took a function h(x) = f(x)-g(x) (continuous) and showed that its integral is 0.
Im planning on showing h(x_1)>0 for some x_1 and h(x_2)<0 for some x_2 and using the IVT to get x_0
but im kind of confused on how to get there

narrow jewel
#

the idea is to assume for contradiction that for all x \in (a,b) h(x) \neq 0

#

BWOC let $\forall x\in (a,b), h(x)\neq 0$

solid kilnBOT
#

kirsch8

narrow jewel
#

then Case 1: $\forall x\in (a,b), h(x)>0$

solid kilnBOT
#

kirsch8

narrow jewel
#

$\int_a^b h > 0$ which is a contradiction. Same for case 2 where $h(x)<0$

solid kilnBOT
#

kirsch8

narrow jewel
#

maybe closed interval instead of open

#

so there exists $x_1,x_2 \in [a,b]$ s.t $h(x_1)>0, h(x_2)<0$

solid kilnBOT
#

kirsch8

narrow jewel
#

then use IVT

simple haven
#

We know that there is some average value for both these integrals

narrow jewel
#

we havent learnt that yet

simple haven
#

This value is ∍f(x) dx/(b-a)

narrow jewel
#

i mean yeah we can say that

#

i guess?

simple haven
#

It is possible to prove (using continuity) that f(x) must equal this value (call it x0) somewhere on the interval [a,b]

#

Similar argument for g

#

These are the same value

simple haven
#

Hth

narrow jewel
#

hmm. is the way i wrote above wrong?

simple haven
#

No, it's not wrong, now that I read it more closely

#

Sorry, actually I rather like your approach better than mine now that I understand it.

narrow jewel
#

i was wondering if id need to add more detail to it, or if it isnt super clear

simple haven
#

Seems ok to me?

#

You demonstrate that h(x) > 0 for some x, and h(y) < 0 for some y, then use the IVT to show that h must equal 0 at some point between x and y. This point is where f and g are equal

narrow jewel
#

:)

#

thank you so much

#

.solved

trim joltBOT
#
Channel closed

Closed by @narrow jewel

Use .reopen if this was a mistake.

trim joltBOT
#
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.

chilly crypt
#

ifff theres two points that i need to plot in a scatter plot how do i label it? Liek for exambl i have two ponits that are [1, 96]

chilly crypt
#

can i label it in some way that indicates theres two of it?

trim lichen
#

!xy

trim joltBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

trim lichen
#

(why would you be making a scatterplot with only 2 data pts)

simple haven
#

I think the idea is that the scatterplot had many different points, but one of the points was repeated once.

#

@chilly crypt what plotting software are you using?

#

If you have many such points then you might want a different plot style than simple scatterplot

#

Especially if the points have an associated uncertainty

trim joltBOT
#

@chilly crypt Has your question been resolved?

chilly crypt
#

context: We already had a scatterplot made of jamovi but for our final performance task we had to draw it digitally or on paperrrr

#

I have two repeating points bcs my bivariate data is study hours and exam scoresss, two students had 1 hour study time and got 96 for their final grade

#

so im drawing mine digitally on ibispainttt

trim lichen
#

oh like

#

oh you mean like two duplicate data points in a bigger set

#

hm...

chilly crypt
trim lichen
trim joltBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

chilly crypt
#

.reopen

trim joltBOT
#

✅

trim lichen
trim lichen
#

so it wouldn't slam the door in our faces

chilly crypt
chilly crypt
trim lichen
#

anyway it looks like there's no universal solution, but one method is to draw the points with some transparency so that duplicates appear darker

chilly crypt
#

thank you so muchh, i will close the channel now if its alright hehe

trim lichen
#

sure

chilly crypt
#

.close

trim joltBOT
#
Channel closed

Closed by @chilly crypt

Use .reopen if this was a mistake.

trim joltBOT
#
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.

lone apex
trim joltBOT
lone apex
#

Guys is my answer & working out correct? I'm trying ai but I'm getting confusing Answers.

#

The working out and answer is mine original.

#

But after I did it

#

I confirmed with ai and its telling me all sorts of things.

#

Is my answer & working out correct?

#

Is my answer & working out correct

#

Or mostly correct?

split chasm
#

no

lone apex
#

Am I mostly correct?

split chasm
#

no

#

after perimeter of circle being pi * D

lone apex
#

How many marks I get out of 4?

split chasm
#

nothing else after that made sense

lone apex
#

How many marks I will get out of 4?

split chasm
#

1

lone apex
#

3

split chasm
#

maybe 0.5

lone apex
#

!

#

3 yes?

split chasm
#

no

lone apex
#

2?

#

OK

#

So how do I get the correct answer?

split chasm
#

apply what's actually stated on your formula

lone apex
#

It's a semicircle

#

The formula is for a circle

split chasm
#

you have 2 semi circle arcs which would together form a full circle
so for simplicity, you can use the circumference of a full circle = pi * D

#

you pi looks like an R, but regardless not what you want

#

you seem to be applying the circumference for a full semi-circle,
however that straight part doesn't contribute to the cirfumference of this shape

trim lichen
#

i think

lone apex
#

Yes

#

Will I get 2 marks?

split chasm
#

1

#

and you also seem to be ignoring the straight parts of the final figure

lone apex
#

@trim lichen

#

Is it 2 marks?

split chasm
#

and not converting units correctly

#

and having cm pop up somewhere

trim lichen
#

i'd have to see the mark scheme to tell you with certainty how many marks you would earn.

split chasm
#

having pi * D present would at most get 1 mark

split chasm
#

but to me nothing else made sense and imo wouldn't get any more marks than that

trim lichen
#

i noticed this issue looking through your work, by the way.

#

regardless of how everything else is (which i did not look through in full), this conversion is incorrect.

#

it's 1 m = 3.3 ft but you treated it as if it were 3.3 m = 1 ft, which is wrong.

split chasm
#

the way i'd allocate 4 marks would be:
lengths of circular arcs (1 mark)
total perimeter of figure (1 mark)
conversion from m to ft (1 mark)
conclusion (1 mark), if properly justified

lone apex
#

She does have enough

#

Conclusion is correct, she does have enough

split chasm
#

based on your flawed calculations it would appear that way, but no

lone apex
# split chasm based on your flawed calculations it would appear that way, but no

Based on the work you showed, your final answer is correct, which is key. However, the working is a bit unclear and contains some unnecessary steps and unit confusion. In an exam setting—where clear, logical working is expected—you might lose a mark for clarity. So overall, you’d likely score around 3 out of 4 marks.

trim joltBOT
lone apex
# trim lichen !nogpt

You correctly:

Recognized that the shape's perimeter includes the two long sides of the rectangle plus the circumference of a full circle (from the two semicircles).

Calculated the straight sections as 2.8 m + 2.8 m = 5.6 m.

Used the circle's circumference formula (π × diameter) correctly, obtaining approximately 6.28 m for the circle.

Added these to find the total perimeter as about 11.88 m.

Converted 40 feet to meters using the conversion factor (40 ÷ 3.3 ≈ 12.12 m).

Compared the two values accurately to conclude that she has enough garland.

These are the main parts you got right in your solution.

#

See ?

#

@trim lichen

#

Its 3 marks

trim lichen
#

ok look

#

if you are going to run to your beloved GPT no matter what we say

#

then it will not matter what we have to say

#

because you will just slap us with more GPT output

#

plus GPT actually gets a lot of shit wrong ESPECIALLY from images full of text.

split chasm
#

if you don't trust me that it'll net you 1 marks, perhaps even 0 depending on how strict the teacher is,
and trust gpt,
then by all means continue what you're doing.

#

first four statements are wrong

lone apex
#

@Ramo

#

@split chasm its telling me

#

My work is worth

#

3/4 marks

#

" Based on a close look at your working and how marks are typically awarded in Functional Skills Level 2 Maths, here's a detailed breakdown of how many marks you'd likely get:

Total marks available: 4

The marks are usually awarded as follows:

MarkCriteria1 markIdentifies the need to calculate the perimeter using 2 straight sides + 2 semi-circles1 markCorrect use of formula for circumference (π × diameter or π × radius × 2)1 markConverts between feet and metres correctly using 1 m = 3.3 ft1 markCompares the required and available lengths correctly and gives the correct conclusion

Your likely score: 3 out of 4

Mark 1 — Perimeter structure: ✓

You recognised that the shape consists of a rectangle and two semi-circles, and you're trying to work with the perimeter — this earns 1 mark.

Mark 2 — Circumference formula: ✓

You referred to π × D for the circle — even if your working was messy, it’s clear you knew the formula — 1 mark.

Mark 3 — Conversion between feet and metres: ✓/✗ (partial)

You attempted to use the 1 m = 3.3 ft conversion, but your use of it was confused (you divided in the wrong direction: “8.8 ÷ 3.3 = 9.6 ft” is backward).
This could be seen as a partial method, but most strict marking schemes would not award this mark — 0 marks here.

Mark 4 — Final conclusion: ✓

You said: “Yes, she has enough.” That’s the correct final conclusion, so 1 mark.

Final score: 3 / 4 marks

With a cleaner explanation of the conversion and fewer unclear steps, you'd easily get full marks.

Would you like me to show you a model 4-mark version of the answer?

"

willow urchin
#

@lone apex continuing to waste helpers time with gpt will earn u a swift ban

trim joltBOT
#

@lone apex Has your question been resolved?

trim joltBOT
#
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.

vocal cobalt
#

how do I know if theres gonna be a sign change at x=0 or not? without calculator (desmos)

vocal cobalt
#

yea basically when does that thing gonna have a sign change

dull pilot
#

do yk wavy curvy

vocal cobalt
#

whats that

trim lichen
#

and nowhere else?

vocal cobalt
#

yea

trim lichen
#

😭

#

you're torturing yourself mate

#

get yourself a file in your notes app or whatever. copy the question. and then do your work properly and properly notated

#

cause like

#

if it's gonna get even a smidge more complicated than "compute this one integral"

#

you're gonna have a bitch of a time w/ it

#

and when all you write is this

#

you make it impossible for yourself to keep track of what is what, you know?

lunar stirrup
trim lichen
#

so like the thing is

lunar stirrup
#

so plot the critical points for where the terms are = 0

trim lichen
#

this work should have been written out as something like this:

$f'(x) = 15x^4 - 20x^3 \ f''(x) = 60x^3 - 60x^2 \ f''(x) = 60x^2(x-1)$

lunar stirrup
#

ykw watch a video on it its too hard to explain over text

solid kilnBOT
trim lichen
#

at the bare minimum

#

so you do not accidentally use the first derivative where you were supposed to use the second, and so on...

vocal cobalt
#

ok but how to solve it

trim lichen
#

you know that a point of inflection for y=f(x) is a point where f''(x) changes sign, yes?

vocal cobalt
#

yea

trim lichen
#

yeah so

#

ok

#

slightly sidestepped but related question, have you solved quadratic inequalities or perhaps polynomial or rational inequalities before, in general?

vocal cobalt
#

? if its part of precalc or algebra 2 then i might have done it

trim lichen
#

it should be a precalc thing

#

i mean like

#

ok, lemme just give you an example question of the kind im asking about

#

$\frac{x(x-7)}{(x-2)(x-4)(x+5)} < 0$

solid kilnBOT
trim lichen
#

would you be able to solve an inequality like this?

vocal cobalt
#

i might immediately crash out

trim lichen
#

💀

lunar stirrup
trim lichen
#

yeah i was hoping to introduce either wavy curve or sign tables

#

a sign table would be more convenient for our usecase

lunar stirrup
#

ohk but wavy curve is more fun

trim lichen
#

$\frac{(x+2)(x-7)}{x-12} > 0$

solid kilnBOT
trim lichen
#

what about this

#

does this still crash you @vocal cobalt

vocal cobalt
#

i might be able to give a try

#

i just pick a number in the interval and plug and chug right?

trim lichen
#

mmmm nope.

#

i would like to avoid plug and chug, and also i don't want to encourage it at all.

#

do the words "wavy curve" or "sign table" ring any bells at all for you

vocal cobalt
#

no 😭

#

sorry

trim joltBOT
#

@vocal cobalt Has your question been resolved?

trim joltBOT
#

@vocal cobalt Has your question been resolved?

jolly saffron
#

so you should look up the wavy curve method

vocal cobalt
#

ok lol

#

.close

trim joltBOT
#
Channel closed

Closed by @vocal cobalt

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.

dull pilot
#

real quick before i ask a less obvious question $\lim_{x \to 2} \frac{\sqrt{1-\cos(2(x-2))}}{x-2}$ is not defined simply because $\sqrt{\sin^2(x-2)} \neq \sin{x-2}$, right?

solid kilnBOT
jolly saffron
#

yes

dull pilot
#

i.e. the left-right handed limits are defined, but this isn't because one would be $\sqrt2$ and the other would be $-\sqrt2$

solid kilnBOT
dull pilot
#

yeah okay i figured

#

thanks

#

.close

trim joltBOT
#
Channel closed

Closed by @dull pilot

Use .reopen if this was a mistake.

dull pilot
trim joltBOT
#
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.

unkempt oriole
#

No

trim joltBOT
#
Channel closed

Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.

#
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.

bright seal
#

$|\frac{3-4i}{4+3i}|^2$

trim joltBOT
solid kilnBOT
#

Task Bot

bright seal
#

This exercise comes to me -1, but wolfram says does 1

#

so wolfram was wrong

bright quarry
#

,w |\frac{3-4i}{4+3i}|^2

bright seal
#

I think it's wrong

soft pendant
bright quarry
bright seal
#

$| -i |^2 = i^2 =-1$

solid kilnBOT
#

Task Bot

bright seal
#

But on Photomath it does 1

#

So strange

simple panther
#

Dude, its the magnitude squared

soft pendant
#

you are doing |a|^2 = a^2

bright quarry
simple panther
#

$|-i|^2=1^2=1$

solid kilnBOT
bright seal
#

🤦

#

Can you explain?

simple panther
#

What website is that?

soft pendant
#

its doing $|a|^2 = a^2$

solid kilnBOT
#

jandro0103

soft pendant
#

$|-i|^2 = i^2 = -1$

solid kilnBOT
#

jandro0103

soft pendant
#

but you have to do

simple panther
solid kilnBOT
soft pendant
#

$|-i|^2 = \sqrt{(-1)^2}^2 = 1$

solid kilnBOT
#

jandro0103

soft pendant
#

this is correct!

simple panther
#

Yes

bright seal
#

Oh well they are making an easy thing in difficult

#

|-3|=3

#

Right?

#

so 3^2=9

#

|-i|=i

#

I^2 = -1

#

Easy

simple panther
#

that's not how mod works for complex numbers

simple panther
soft pendant
#

|-3| = $\sqrt{(-3)^2} = 3$

solid kilnBOT
#

jandro0103

soft pendant
#

ez

simple panther
solid kilnBOT
soft pendant
#

these are basics things !

bright seal
soft pendant
#

@simple panther

bright seal
#

But here I have drawn the absolute value in another way

soft pendant
#

but why in the (2) they writed the same thing ?

simple panther
# bright seal

That website probably doesn't treat |...| the same way

#

So u mean 1 website is right while every other source is wrong?

soft pendant
#

guys sorry but in the (2) of my screenshot is |z1/z2| = |z1|/|z2| if z2 is not 0

#

right ?

#

because they writed the same thing twice

#

can you confirm ?

bright seal
#

I understand now that there are more use than ||

bright seal
#

Ei

#

@simple panther !occupied

#

!occupied

trim joltBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

soft pendant
empty orchid
bright seal
empty orchid
bright seal
#

Photomath

empty orchid
#

Yeah, probably wrong.

#

|-i|=1.

#

And obviously, 1^2=1.

bright seal
#

|-3|=3

#

3^2=9

empty orchid
#

Also notice that $z\cdot\bar{z}=|z|^2$.

solid kilnBOT
bright seal
#

|-i|=i

#

i^2=-1

empty orchid
#

Huh?

#

No.

bright seal
#

,w |-i|

empty orchid
#

The absolute value defines a distance from the origin of a complex number.

bright seal
#

Mmm

empty orchid
#

Hence, it can never be complex.

#

Do you understand that?

bright seal
#

$\rho=1$

solid kilnBOT
#

Task Bot

bright seal
#

So you have to find Rho?

#

The radius?

empty orchid
bright seal
#

👍

#

Clear

empty orchid
#

Like, the polar definition is $a+bi=|z|(\cos(\theta)+i\sin(\theta))$, for $\theta=\arctan(\frac{b}{a})$.

solid kilnBOT
empty orchid
#

z=a+bi in this case.

bright seal
#

Thanks!

empty orchid
#

(Sorry about the other day.)

bright seal
#

.close

trim joltBOT
#
Channel closed

Closed by @bright seal

Use .reopen if this was a mistake.

trim joltBOT
#
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.

wraith hinge
#

Can someone please explain how to do the first one?

wraith hinge
#

I know that we have to use some identity here but I don't know what the first step is supposed to be...

simple panther
#

Try squaring the given equation

wraith hinge
#

You mean x - 1/x = 3?

jolly saffron
#

for the second one find 1/x, and factor out x^2 from the quartic

#

you'll get something similar

#

(a quadratic in x + 1/x)

#

oh you didn't ask for the second one mb

hollow cypress
#

id just solve for x....

#

👀

trim lichen
hollow cypress
#

tbf in an exam setting where I cant figure out what to do

#

and this would show up

#

it's not THAT bad

wraith hinge
#

WAIT

#

I think I got it.

surreal bone
#

m^3+y^3 = (m+y)(m²+y²-my)

frail heron
#

Phenomenal

wraith hinge
#

Alright, thanks everyone! My answer matches. Can't believe I got stuck on such a simple problem after doing so many hard ones. 😭

#

.close

trim joltBOT
#
Channel closed

Closed by @small bluff

Use .reopen if this was a mistake.

trim joltBOT
#
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.

upper owl
#

Would the local minimums be 1 and 2?

trim joltBOT
jolly saffron
#

why?

upper owl
#

I’m not sure if the sharp turn is a local

jolly saffron
#

why 1 specifically

#

it is

queen beacon
jolly saffron
#

the only requirement for a minima is f(x - h) < f(x) < f(x + h)

queen beacon
#

The only thing that matters is that everything around it is bigger yes

upper owl
#

Ok thanks

jolly saffron
#

are my inequalities right lol

#

also don't forget x = 7 in case you did

upper owl
#

It’s asking for the values and x=7 is the same value

#

As the dot

queen beacon
#

Yes

upper owl
#

So the values are just 1,2

formal jasper
#

am i rememberign it wrong

queen beacon
#

Don’t forget that’s a local minimum too but ye

#

No

formal jasper
#

oh

upper owl
#

they only giving the graph

#

But that’s a way to find it

formal jasper
upper owl
#

Yes

formal jasper
#

thanks :3

queen beacon
#

Yes

upper owl
#

.clise

#

.close

trim joltBOT
#
Channel closed

Closed by @upper owl

Use .reopen if this was a mistake.

trim joltBOT
#
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.

unborn fossil
#

need a bit help 🙏

trim joltBOT
unborn fossil
#

im just lost in general

split chasm
#

first determine the:
current total from the first 10 reviews
required total from all 20 reviews

unborn fossil
#

would it be 75 * 10?

#

aka 750

split chasm
#

currently, yes

unborn fossil
#

alright, but thats just an average 😭

#

i get it tho, now what?

split chasm
#

wdym

#

what's just an average

unborn fossil
#

the 750?

split chasm
#

750 is the total from the first 10

unborn fossil
#

or thats the addition considering teh average

#

right

#

alright, so what would we do from here?

split chasm
#

required total from all 20 reviews

#

what's the minimum total rating needed to have an average of at least 85

unborn fossil
#

would that be 85 * 10? because we already have the first 10.

split chasm
#

no

#

forget about the 10 for this part

#

85+ is the average from 20 reviews

unborn fossil
#

yes, but you cannot change the average of the first 10 reviews

split chasm
#

yes

unborn fossil
#

but it would be 20 * 85 so 1700

split chasm
#

but right now, we first want to know to total

unborn fossil
#

alrighty

split chasm
#

and now you can subtract the total of the first 10 to determine how many points you'd need to gain

unborn fossil
#

so 1700 - 750?

split chasm
#

yes

unborn fossil
#

aka 950

split chasm
#

and now consider the best case scenario

unborn fossil
#

all 100's?

#

for 9 tests

split chasm
#

yes

unborn fossil
#

not 10 because

#

we want to find the minum

#

so 9 * 100

#

900

#

and then 950 - 900?

#

so 50?

split chasm
#

yes

unborn fossil
#

ahh ty! that helps

#

have a good day

#

.close

trim joltBOT
#
Channel closed

Closed by @unborn fossil

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.

soft pendant
trim joltBOT
soft pendant
#

how can i prove that

#

i think it has to do with binomial formula

surreal bone
#

what about using sin(x+y) ?

#

sin(x+y) = sin(x)cos(y)+sin(y)cos(x)

soft pendant
#

oh wait i need to go eat

#

ill back soon

lunar stirrup
#

jokes

#

first factorize the rhs

#

,w factorize 16 cos^4 theta - 12 cos^2 theta + 1

soft pendant
#

im back

lunar stirrup
#

nvm dont factorize the rhs

#

yeah split sin 5theta as sin (2 theta + 3theta)

soft pendant
#

i cant touch the rhs

#

i need to use the binomial formula

#

i have to use this

#

<@&286206848099549185>

hard musk
# soft pendant

is this further maths becuase you would have to use the imaginearly of the expansion of sin5x i guess?

soft pendant
#

yes

#

.close

trim joltBOT
#
Channel closed

Closed by @soft pendant

Use .reopen if this was a mistake.

hard musk
soft pendant
#

yes it was connected to the previous exercise

#

sorry

hard musk
soft pendant
#

yes wait

daring viper
#

oh with complex numbers

hard musk
soft pendant
#

In the end I skipped the conversions because I was bored, so I wrote the result right away

soft pendant
#

If you are interested you can do it yourself from the start

daring viper
#

very nice method.

soft pendant
#

i started from (a) and then do (b)

#

but you can start from (b) and also do (a)

#

this is what the book does

daring viper
#

what book is this?

soft pendant
#

its complex - variables - schaum - 2 edition

daring viper
#

ic thanks

trim joltBOT
#
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.

soft pendant
#

hello

trim joltBOT
soft pendant
#

z = -15 -8i

#

find the square root

#

i found r = 17

solid kilnBOT
#

jandro0103

soft pendant
#

but i noticed that the point x = -15 , y = -8 is in the third quadrant

#

but theta is in the fourth qudrant

#

how can i fix ?

trim lichen
#

0.49 rad is not in the fourth quadrant

soft pendant
#

i always confuse when i have to fix the angle using pi,-pi etc

trim lichen
#

0.49 rad is in the FIRST quadrant

#

did you find it as arctan(Im/Re)?

soft pendant
#

why i said fourth 😢

#

anyway

#

z is in the third quadrant

trim lichen
#

did you find 0.49 rad via arctan(Im/Re)

soft pendant
#

yes

trim lichen
#

right then you are off by half a turn

#

do you like your arguments -pi to pi or 0 to 2pi?

#

or do you not care

soft pendant
#

i like use 0 to 2pi

trim lichen
#

ok in that case you have to fix it by adding pi

#

i was briefly considering sending this but that might have gone badly

#

(with the joke being that you need to adjust by pi or -pi but it does not matter much which one you go for)

soft pendant
#

could you explain to me why? I mean otherwise next time I wouldn't know how to do it again

trim lichen
#

do you understand why you are off by a half turn

trim lichen
#

:P

soft pendant
#

because im in the first quadrant so to reach the third i need to do hald turn

#

isnt it pi/2 ?

trim lichen
#

yeah so because of your principal argument range of [0,2pi) you need to add pi to stay in range

trim lichen
soft pendant
#

i mean

#

since i need to do half turn

#

isnt it pi/2?

#

this

#

that is, to go from the first to the third quadrant I don't rotate 90 degrees?

#

oh maybe with pi/2 im going in the second quadrant

#

not in the third ?

#

@trim lichen is this the reason ?

trim lichen
#

sure

#
  • 2pi is a full turn
  • 1pi is a half turn
  • ½pi is a quarter turn
soft pendant
#

okay thanks

#

.close

trim joltBOT
#
Channel closed

Closed by @soft pendant

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.

bronze jetty
#

anyone plz help in this ques i think only A and C should be answers ... It is said that ABC are answers anyone plz confirm

bronze jetty
#

<@&286206848099549185>

trim joltBOT
#

@bronze jetty Has your question been resolved?

trim joltBOT
#

@bronze jetty Has your question been resolved?

trim joltBOT
#

@bronze jetty Has your question been resolved?

#
Channel closed

Closed by @bronze jetty

Use .reopen if this was a mistake.

trim joltBOT
#
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.

harsh siren
trim joltBOT
harsh siren
#

a friend sent it to me

trim lichen
#

looks very ugly

trim joltBOT
#

@harsh siren Has your question been resolved?

undone gorge
# harsh siren

It's a lengthy method but you know F is the origin, so you can find G's cordinate.
Then find H's cordinate using polar method:
x = x0 + r * cos(theta) and
y = y0 + r * sin(theta)
And do the same for J and I.

#

You can then find the parabola using 3 points

#

And you have the line passing through FG and cuts the parabola at A and E

#

Find A and E by substituting the line in parabola's eqn.

#

Then use distance formula

trim joltBOT
#
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.

sweet turret
#

the answer is not polynomial 3

trim joltBOT
sweet turret
#

is it describing polynomial order 2?

fringe thunder
#

ts pmo!

clear cloud
trim joltBOT
fringe thunder
fringe thunder
#

or maybe you can hurry ybau a little

clear cloud
#

!occupied

trim joltBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

fringe thunder
#

!occupied

trim joltBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

fringe thunder
#

Never stop learning. He who stops learning, stops living.

#

!occupied

trim joltBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

clear cloud
sweet turret
#

it goes up, reach peak, and go down

#

kind of describes -x^2

split pulsar
clear cloud
#

Its generally exponential in physics

sweet turret
#

the answer is polynomial 2 💀

#

this question doesnt specify clearly

clear cloud
#

Yeah ok why not

sweet turret
#

how would it be exponential

#

when theres a fall

clear cloud
#

Exponential can decrease

#

Just get a negative thing in it

sweet turret
#

yea but the question wants increase and decrese

clear cloud
#

e^-x²/2

#

Gaussian

#

,w graph e^(-x²/2)

sweet turret
#

wtf ok im not that deep

west sleet
#

I think the intended answer is just order 2

clear cloud
#

Anyway

lunar stirrup
trim joltBOT
#

@sweet turret Has your question been resolved?

#
Channel closed

Closed by @sweet turret

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.

full dock
#

i need help with starting

trim joltBOT
full dock
#

do i have to put this into parametric form?

dusky thunder
#

what do you know about parallel planes and their normal vectors

full dock
#

the normal vector n is orthogonal to the vector x-p

dull pilot
#

thats a start

full dock
#

amd a direction vector is a nonzero vector in R3 is parallel to the plane in R3

dusky thunder
#

is there a relation between two parallel planes and their normal vectors is what i meant

full dock
#

ohh

#

wait

#

if two planes are parallel

#

their normal vectors can be expressed in terms of some scalar?

dull pilot
dusky thunder
#

not exactly

dull pilot
#

vector in terms of a scalar?

full dock
#

like

#

n = kn or something

#

where k is real number

dusky thunder
#

i think they meant one normal vector can be expressed as a scalar multiple of the other normal vector

#

the thing about normal vectors is that they are directional so saying they can be scaled is obvious. one useful fact though is

#

parallel planes have the same normal vectors

full dock
dusky thunder
#

it is akin to saying two parallel lines have the same slope

#

now moving on, do you know how to express a plane equation using the normal vector

full dock
#

We got taught general and parametric vector form of a plane

#

But I’m not sure when to use which

trim lichen
#

there's kinda no way to teach that exactly, you just gotta practice a bunch and develop a feel for it

trim joltBOT
#

@full dock Has your question been resolved?

full dock
trim lichen
trim lichen
#

you don't actually need to do any fancy form conversion here at all

#

you need to know two things:

  • from an equation of a plane in the form ax + by + cz + d = 0, equations of planes parallel to it can be produced by messing with the constant term d
#

(and possibly multiplication of the entire eq by a constant)

#
  • the plane you're looking for needs to both arise in this way and pass thru P
#

clearly the ones that begin with -15x - 3y ... could not have arisen from multiplying -x-3y-3z+21=0 by anything

#

so those are out

#

and you now need to decide between option 1 and option 2

#

do you understand thus far

full dock
trim lichen
#

mm no

#

i think you're kinda overthinking it rn

#

or maybe im not exactly helping it by yapping about answer option elimination

#

the upshot is like

#

ok, we want a plane parallel to -x - 3y - 3z + 21 = 0 which also passes thru P = (2, -2, 3)

#

yes?

full dock
#

yes

trim lichen
#

the way we do this is we replace the constant term (and JUST the constant term! keep everything else as-is) with a blank space:

-x - 3y - 3z + _____ = 0
#

and now ask ourselves the following question:

#

what needs to go into the blank to make the point P satisfy this equation?

full dock
#

ohh okay

#

would we substitute in our point?

trim lichen
#

yes

full dock
#

is it a good idea if i assign the blank space a variable or smth

trim lichen
#

yes it is

full dock
#

so i get d=5

#

well the blank spot

#

so -x - 3y - 3z + 5 = 0

#

ah which is the first option

full dock
# trim lichen yes it is

also one more question, im not sure how to start this i know a unit vector e1 for example has <1,0,0> for R3 but is it talking about that here?

trim lichen
#

busy sorry

full dock
#

allg

#

.close

trim joltBOT
#
Channel closed

Closed by @full dock

Use .reopen if this was a mistake.

chilly bobcat
#

hi

#

is this still alive

#

by chance

trim joltBOT
#
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.

trim joltBOT
#

Please don't occupy multiple help channels.

#
Channel closed

Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.

#
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.

tame hull
#

"Casper owns three cars of the same brand and drives to work with one of them. Each morning, he randomly picks one car and one key. Unfortunately, the cars don't always start even if he picks the correct key. Car 1 starts with a probability of 0.7, Car 2 with a probability of 0.5, and Car 3 with a probability of 0.3. What is the probability that the car starts on the first attempt?"

exotic pine
#

i think you can split it into the chance of correct car+key combo, and the average chance of the car starting

#

the average wihld be 0.7+0.5+0.3/3=0.5, so 1/2 chance of starting first try assuming correct car+key

tame hull
#

in the solution book it says that the answer is 1/6

faint stream
#

Imma try this.

tame hull
#

I solved it

tribal juniper
#

But nice u solved it, close it with .close then

tame hull
#

my bad

exotic pine
tribal juniper
#

and three cars

main sigil
tame hull
# exotic pine ?

U needed to get the amount of kombinations of cars and keys, 1/3 x 1/3

main sigil
#

you'd just multiply that average by 1/3

exotic pine
# tribal juniper there are three keys

the average wihld be 0.7+0.5+0.3/3=0.5, so 1/2 chance of starting first try assuming correct car+key? then i wanted him to calculate the probability of getting the same car and key, which would be 1/3, so 1/3×1/2=1/6?

tame hull
#

and then 1/9 x the average

#

.close

trim joltBOT
#
Channel closed

Closed by @tame hull

Use .reopen if this was a mistake.

faint stream
#

@tame hull just in case, this might help.

#

It's still the same as his, just a little longer.

trim joltBOT
#
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.

broken cave
#

Can a 7 degree equation be a straight line?

broken cave
#

Is this 7 degree equation a straight line ?

fleet bear
#

One root doesn't imply straight line

broken cave
#

,w plot x^7+14x^5+16x^3+30x-560=0

broken cave
#

I think I zoomed too much

fleet bear
#

Mhmm

clear cloud
fleet bear
#

Wrong axis

broken cave
#

Bro what

fleet bear
#

-1500 < y < 1500

#

-5 < x < 5

#

Based off wolfram

broken cave
#

Okay got it

#

Thanks

#

It's not a straight line

#

It just doesn't have any turning points so yeah

#

It's not a string line because it has different values for diff x

#

Straight*

#

Yeah

#

.close

trim joltBOT
#
Channel closed

Closed by @broken cave

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.

vocal cobalt
#

what method do I use to differentiate this? do i first do ln on both function to simplify?

lunar stirrup
#

product rule?

#

oh nevermind

#

just saw the x^2 term

vocal cobalt
#

yea i just noticed that

#

thanks

#

.close

trim joltBOT
#
Channel closed

Closed by @vocal cobalt

Use .reopen if this was a mistake.

trim joltBOT
#
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.

short raft
#

all info is shown on diagram, the radius were looking for is smaller than the given one (r1 < r2, r2 = 9)
ive tried making a perpendicular from O2 to the other circle (indicated with red lines) but it doesnt get me anywhere
-# ...i swear if its something plain obvious again

trim lichen
#

do you have a name for the bottom-most vertex of the red triangle

#

if not i will just call it X

short raft
#

x is fine yeah

trim lichen
#

is $\angle O_1XO_2$ meant to be right?

solid kilnBOT
short raft
#

yep

trim lichen
#

ok, then $XO_2 = 12$, $XO_1 = 9-r$ and $O_1O_2 = 9+r$

solid kilnBOT
short raft
#

yeah

trim lichen
#

and XO1O2 is a right triangle

short raft
#

yep

#

ive gotten to that point but i dont know what to do, pythegoream doesnt seem to work as theres simply only 1 side we know about

#

(XO2)

trim lichen
#

what do you mean

#

pythagoras works just fine

#

you get an equation in r

#

write it down and solve it

short raft
#

ima trust you and try

trim lichen
#

do it

short raft
#

WHATTTT

#

THATS SO CLEVER

#

anyways i get sqrt root of 72

trim lichen
#

sqrt root is a bit silly

#

it's like ATM machine

#

it already stands for square root :P

#

... but show your work?

short raft
#

oh yeah xD

trim lichen
#

i think you've gotten something wrong here but i wanna see where and what

short raft
#

oh

#

i uhhh forgot that i need to use (a - b)^2 instead of just doing a^2 - b^2