#help-49

1 messages · Page 225 of 1

lyric charm
#

the woman's plan of action is to try keys one by one, discarding the wrong ones, until she finds one that works

twilit field
#

yes

lyric charm
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i would argue it makes tons more sense to consider the sample space here to consist of all permutations of all n keys

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corresponding to the order in which they're drawn from her keychain

viscid jolt
#

hmm

lyric charm
#

succeeding on the k'th try now means that the good key occupies the k'th spot in the permutation

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while the others can be arranged in whatever way

twilit field
#

so I have to permute (n-1) keys

lyric charm
#

if you wanna phrase it that way, sure.

twilit field
#

Which can be done in (n-1)! ways

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and the size of the sample space would be n!?

lyric charm
#

yes

twilit field
#

and there are k ways to place the right key

lyric charm
#

no

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there is only one

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the good key has to go in exactly the k'th spot

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it has nowhere else to go, bc it has to be drawn on exactly the k'th try and at no other point

twilit field
#

so the answer would simply be (n-1)!/n!=1/n

lyric charm
#

yes

twilit field
#

Same question, but she doesn't discard the previously tried keys this time

fallen sparrow
#

interesting question

fallen sparrow
lyric charm
#

are you at the stage where the words "independent events" have appeared

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(yes or no, no wrong answer except if you decided to lie to me)

twilit field
lyric charm
#

mkay

fallen sparrow
lyric charm
#

thing is though now defining the sample space and the probability measure is going to be tricky if we're doing it in full detail

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(bc the girl might take arbitrarily long to find the damn key)

twilit field
twilit field
lyric charm
#

but the idea is still that the first k-1 tries have to fail and the k'th has to succeed

twilit field
#

yes

lyric charm
#

i guess maybe we could now cap ourselves to k attempts and consider that either the girl gives up if she doesn't get it on the k'th try or that we don't care what happens beyond the k'th try anyway

twilit field
#

so the probability would be (n-1)^k/n^k

lyric charm
#

(n-1)^(k-1) / n^k

fallen sparrow
#

what ann said

twilit field
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okay

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thanks

molten bay
#

Can i join the party?

hard shard
#

heres a simple alternative: shuffle the keys like a deck of cards, what is the probability key k is the right k?

lyric charm
#

what party?

hard shard
#

right key*

lyric charm
hard shard
#

i mean, i guess

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but that doesnt affect the probability at all

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if you imagine she tries each key anyway even after getting the right key, you get a sequence

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(at the end)

hard shard
#

the probability of key k being right is independent of the other keys

twilit field
#

Another question

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uh

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, wait a bit

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thanks everyone

#

.close

midnight plankBOT
#
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midnight plankBOT
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midnight plankBOT
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willow spindle
#

if $\alpha$ and $\beta$ are the roots of $x^2+x+1$ and $\gamma$, $\delta$ are the roots of $x^2+3x+1=0$ then value of $\alpha^{\delta}+\beta^{\gamma}+\alpha^{\gamma}+\beta^{\delta}$ is

grand pondBOT
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Madhup

willow spindle
#

Pls help guys

grim vector
#

!msgdel

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#

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midnight plankBOT
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barren wharf
#

Find integer solutions to:

x^(2y) + xy^15 - x! + y!/(5!) + 2^x + x = 7952735876771577277868825991

barren wharf
#

!status

midnight plankBOT
#
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2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
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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
barren wharf
#

,w factor 7952735876771577277868825991

grand pondBOT
barren wharf
#

Interesting.

thin relic
#

$$ $x^{2y}$ + $xy^{15}$ - x! + $\frac{y!}{5!}$ +$ 2^x$ + x = 7952735876771577277868822995 $$

jaunty ivy
#

where did u get this question

grand pondBOT
#

ALPHA NEEL

$$ $x^{2y}$  + $xy^{15}$ - x! + $\frac{y!}{5!}$ +$ 2^x$ + x = 7952735876771577277868822995 $$
```Compilation error:```! Display math should end with $$.
<to be read again> 
                   x
l.49 $$ $x
          ^{2y}$  + $xy^{15}$ - x! + $\frac{y!}{5!}$ +$ 2^x$ + x = 795273587...
The `$' that I just saw supposedly matches a previous `$$'.
So I shall assume that you typed `$$' both times.```
barren wharf
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My friend.

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,w x^(2y) + xy^15 - x! + y!/(5!) + 2^x + x = 7952735876771577277868825991

grand pondBOT
austere blade
#

this question looks awfully hard though

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judging from the massive number

jaunty ivy
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its a troll

barren wharf
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Just because you can't do it does not mean I am a troll.

thin relic
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$x^{2y}$ + $xy^{15}$ - x! + $\frac{y!}{5!}$ +$ 2^x$ + x = 7952735876771577277868822995

grand pondBOT
#

ALPHA NEEL

thin relic
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This is it

tawdry laurel
barren wharf
tawdry laurel
#

Have you tried plotting on a 3D graph?

barren wharf
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Nope.

austere blade
tawdry laurel
barren wharf
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how

tawdry laurel
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You can get triples of solutions

tawdry laurel
barren wharf
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What is the third variable

tawdry laurel
jaunty ivy
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even if u could bound this, u'd have far too many testcases for it to be a reasonable question.

tawdry laurel
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just graph it lmao

barren wharf
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okay

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I get sheets of metal.

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<@&286206848099549185>

snow dawn
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Ok

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Time to help my name sake

snow dawn
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Neat.

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Yeet

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5 factorial is 120

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Multiply that mass of number at rhs by 120 and solve for x and y the exponential way using exponential laws if needed

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Also idk why you would ever need or get to solve this kind of question @barren wharf

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Just skip it

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It adds no value to your life even if it comes to exam

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Solving it would most likely make you fail the exam

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Also do I know you?I have so many stalkers irl who make up these ids and come to my servers with intentions I don't want to talk about 👀

midnight plankBOT
#

@barren wharf Has your question been resolved?

midnight plankBOT
#
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primal owl
#

this is a question I've been sort of avoiding for a while and i wanna get to it today :p
the first part (finding the x coordinate of the stationary point) was simple enough (x=pi/12). the derivation function turned out to be dy/dx = (3e^3x)(sin3x-cos3x)/sin²3x

idk how to go about finding the second derivative tbh it just looks so tedious 😭 is there any other way to determine the nature of the stationary point?

primal owl
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i tried to analyze the original function and found that e^3x is greater than zero in the interval (and beyond that obviously) and the sin(3x) is negative between [pi/3, pi/2) but idk if I can use that info :(

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in my mind since pi/12 is less than pi/3 then it should be a maximum point but idk

austere blade
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I don't think there's a way to dertimine the nature of the stationary point without doing the second derivative test

primal owl
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aw :(

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idk if my exam board would give a question THAT long though so i assumed there might be a clever way to do it :p

austere blade
primal owl
austere blade
primal owl
#

i am NOT differentiating that thing tho if they expect me to do that 😰

austere blade
primal owl
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it doesnt, its a question from my book and they dont show that there (which is recommended by my exam board so its supposed to be a primary resource apart from past papers)

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BASICALLY IF YOU CAN GET THE TEXTBOOK QUESTIONS u can move onto past papers

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and i cant get this one so im nervous abt it

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i left it 2 days ago but its been lingering in my head :D

austere blade
primal owl
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yeah im aware some can acc be more difficult than actual exam question

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i guess this is one of them

austere blade
primal owl
#

lemme js try finding the second derivative again atp

primal owl
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ok im procrastinating lemme js do it

austere blade
midnight plankBOT
#

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#
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snow dawn
#

3^x = x⁹. Solve for x

midnight plankBOT
#
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
snow dawn
#

I think we need to make 3 and x equal in some way

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Which is not possible

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I think this question more suitable somewhere else

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.close

midnight plankBOT
#
Channel closed

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small jasper
#

lambert function time

snow dawn
#

.reopen

midnight plankBOT
#

snow dawn
#

Nvm

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How do we use Lambert W

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<@&286206848099549185>

midnight plankBOT
#

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.

snow dawn
#

Quelle?

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This is my first ping

hushed mauve
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it's only been 5 mins

lusty furnace
snow dawn
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Oh I see sorry

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What is e? Euler?

summer geode
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yes

lusty furnace
snow dawn
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What does W do then

lusty furnace
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Reminder that $a^b = e^{b \ln(a)}$

grand pondBOT
#

Médicis

summer geode
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W is the inverse of $f(x) = xe^x$

grand pondBOT
#

Yeatte

summer geode
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so $W(f(x)) = x = W(xe^x) = x$

grand pondBOT
#

Yeatte

summer geode
#

might be some extra conditions catshrug

snow dawn
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Let's see

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Is W = a^i?

summer geode
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it's a multivalued function so inverse might not be the best word

visual tiger
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W(xe^x) = x is not always true, depending on which branch of lambert function you take

summer geode
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^

snow dawn
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Actually its

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we^w = x

summer geode
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w isn

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w isn't a number

snow dawn
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It's a complex number?

summer geode
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no, its a multivalued function

visual tiger
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it's true though that W(x)e^W(x) = x

snow dawn
#

So tell me the steps to solve the question please

summer geode
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you didn't post a question to solve?

snow dawn
visual tiger
summer geode
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oh the previous thing before this?

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mm

visual tiger
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this one actually you can possibly solve without lambert

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suppose x = 3^t

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(x has to be positive because x^9 = 3^x is)

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and solve for t

snow dawn
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3^(t)9 = 3^3^t

visual tiger
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mmmh well even after simplifying this is a bit sad

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you gotta "spot" the solution basically

snow dawn
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I.e. 3^9t = 3^3^t

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So 9t = 3^t

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I guess we raise both sides to the power of 1/(t)

visual tiger
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not really

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this is all about guesswork now, or lambert

mighty flicker
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maybe consider log to base 3?

snow dawn
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What are we guessing

visual tiger
visual tiger
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9t = 3^t

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you can divide by 9 if you want and that changes to t = 3^(t-2)

snow dawn
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Trial and error method 🙆

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Why I chose to raise both sides to 1/(t)

mighty flicker
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wait i think im cooking something

snow dawn
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Was to get rid of the exponent t on 3

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We get a more simpler equation

visual tiger
snow dawn
#

(9t)^1/(t) = 3

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Now we have to try and eliminate one t

visual tiger
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put in spoilers at least please

snow dawn
#

Please don't give answers 🙂

mighty flicker
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oopsies

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welp dm me if you want the method

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or just ping

snow dawn
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Just write it here for Pete's sake

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Actually my question now is

mighty flicker
#

alr then

snow dawn
visual tiger
snow dawn
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Then we just have to find a value of t that satisfied that equation

visual tiger
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also, while the first solution is obvious, there is another... and can't be expressed without lambert W

snow dawn
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Which is not a method in its own right

visual tiger
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one of them literally can't be given in exact expression without W lambert function

visual tiger
snow dawn
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You said to find a value of t

snow dawn
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If it is to find all solutions

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That method can't work

visual tiger
snow dawn
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But it's a guessing thing with no real way of actually getting there. It will take eternity since I see numbers up to 5 don't satisfy it

visual tiger
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I'm just you'd rather write your solution as "x = 12" rather than "x = 2^W(1/2)" or something

visual tiger
snow dawn
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?

visual tiger
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if you went up to 5

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then you miscomputed something

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let's do the computations together then

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t = 1, what is 3^t, and what is 9t

mighty flicker
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maybe the way to solve it is to convert it to the simplest form possible and start guessing from there

visual tiger
snow dawn
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For 1

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We get 9 = 3

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For 2 we get 4.24 = 3

visual tiger
mighty flicker
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simplest form would be ||a+2 = 3^a where t = 3^a||

visual tiger
snow dawn
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Yes

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(9 . 2)^1/(2) =3

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Sqrt. 18 = 3

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4.24 = 3

visual tiger
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ok... do that form if you prefer

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but computing n-th roots is gonna be bad for you in the long run

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what about t = 3

snow dawn
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Plus

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We can't use calculators, we can simply tell that there are no integral roots to the expression simply by looking at it

visual tiger
#

if you can't use calculators

snow dawn
#

Sqroot. Of 18 has not integral roots

visual tiger
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then WHY are you using the (9t)^1/t = 3 form

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instead of 9t = 3^t

snow dawn
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Because 9t^1/(t)is easier for me

visual tiger
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ok... if you say so

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what about t = 3

snow dawn
#

I am well equipped with the laws of exponentials

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Now we can see that

visual tiger
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it's (9t)^1/t

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not 9t^1/t

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jic

snow dawn
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True that

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(9 . 3)^ 1/3 = 3 is actually a true equation

visual tiger
#

that you missed the first time

snow dawn
#

The cube root of 27 is 3

visual tiger
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ok

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then you can notice that the bigger t is from there on, the smaller (9t)^1/t is gonna be

snow dawn
#

So that means that t is 3

visual tiger
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t = 3 is the only "nice" solution yes

snow dawn
#

That means x =3³ = 27

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Then how do we find the other sol.

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It will be a long journey with no fruitful results

visual tiger
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either expressing through lambert W function, or we can just prove it exists and is the only other solution

snow dawn
#

But thanks 🙂

visual tiger
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which one you prefer

snow dawn
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Lambert W affcorse

visual tiger
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ok

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well

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9t = 3^t

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is the same as $9t = e^{t\ln 3}$

grand pondBOT
#

Raphaelisius Maximus MMIII

digital juniper
#

i am suffring to a be an average in math
so help me to solve this

visual tiger
#

I don't know if you use ln or log for natural log

midnight plankBOT
visual tiger
#

so

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let's just write everything together

snow dawn
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Natural log is definitely ln

visual tiger
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$9te^{-t\ln 3} = 1$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

now we try to make some "Xe^X" appear

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the exponent can't really be changed

snow dawn
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Wait did you just transpose the exponential by just making it negative?

visual tiger
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so we'll make the multiplicative coeff match

visual tiger
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exponent rules

snow dawn
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Oh yes the e got multiplied to 9t as well didn't see

visual tiger
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now, we want the left hand side

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to be Xe^X

snow dawn
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I don't see any W here

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What's the issue

visual tiger
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you'll see when we start needing it

snow dawn
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Ok

visual tiger
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remember that Xe^X = a means that X = W(a)

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and that's when it'll inevitably appear

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make the multiplicative coefficient match the exponent:

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$-t\ln 3 e^{-t\ln 3} = -\frac{\ln 3}{9}$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
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So W is the name of the function of a. When a is x, then?

visual tiger
#

?

visual tiger
snow dawn
lusty furnace
snow dawn
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Does this mean

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That we replace a with x

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Or something else it means

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Which implies, Xe^X = X

visual tiger
#

no?

lusty furnace
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a reciprocal function is named $f^{-1}$ and is defined as $f^{-1}(f(x)) = x$

grand pondBOT
#

Médicis

visual tiger
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a is some expression

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if you apply "xe^x" to X and you get a

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that means that if you "undo xe^x" to a, you get back X

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that's what an inverse function is

snow dawn
#

Forgive me I have never been taught Lambert function 🙏

visual tiger
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take some positive number a

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and now I have a mystery number x, positive

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such that x^2 = a

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how do I find x

snow dawn
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I think I can use my first method

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Directly in this question

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So the question is 3^x = x⁹

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Can we raise both sides to the power of 1/(9) to isolate x?

visual tiger
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if you want to?

snow dawn
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We get, (3)^x/(9) = x

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Now we have to separate variables

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Such that x and x both come to the left hand

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How do we do that though

visual tiger
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you can have both x's on the same side if you want

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but you won't be able to "separate" them

snow dawn
visual tiger
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$3^{\frac x9} = x$

$1 = x3^{-\frac x9}$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
#

Now we have to make x single

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Not possible I guess

visual tiger
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no

snow dawn
#

Your method serves it better

visual tiger
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lambert is almost always the only way in those problems

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if you have some number x, in terms of its exponential

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it's almost always lambert

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no way around it but guesswork (which doesn't give you all the solutions)

snow dawn
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Wait

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The next step should be

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This

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Hmm

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Something is in my mind

tropic ice
#

I haven't read the whole conversation but if you want on YouTube there is a channel called Prime Newtons that explains the W function in a very simple way, at least I learned about it for the first time through that channel so in case I recommend it to you

snow dawn
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Sure

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Maybe

visual tiger
snow dawn
#

I can further simplify this to

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By raising both sides to the power of 1/x

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We get that (3)^1/(9) = x^1/(x)

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We got both x on the rhs

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We can rewrite them to the LHS for convenience

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Now it looks pretty straightforward doesn't it?

visual tiger
snow dawn
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We think

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Let us see

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3 and x are not the same bases

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So we can't assert that the exponents are equivalent to each toher

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So we have to make 3 and x equal to each other as I stated earlier

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Which can't work because x and 3 were never meant to be equal and x = 3 doesn't satisfy the equation

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I am cooking sumthing

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There is a method I normally use in integration

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I call it the blindfold method

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We simply make two powers that when they multiply each other they give 1. So raising the equation to those powers will still give us the same equation, but it gives room for manipulation

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Technically this is allowed since the both equations are equivalent

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We use this whenever we want to "manipulate" something like you get what I am saying

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So let's take any power a

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Let's use 3 for convenience

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3 × 1/(3) = 1

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These powers can be used for manipulation

mighty flicker
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but you did that manipulation with the answer in your mind tho

snow dawn
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Normally what I do in integration is that this gives me a way to you know, get it in a way that it actually allows me to use one of the laws

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And I arrive at the solution

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This is called manipulation

visual tiger
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I doubt your manipulation will get you anywhere but you're free to try. I do feel like you would be wasting your time tho

snow dawn
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Here the only applicable law is (a^m)^n = a^m.n

snow dawn
#

Our problem is that we can't find all solutions

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So I am deriving a technique that solves it as an algebraic equation

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Which will obviously give us all real solutions

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Here

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If we try to simplify it then we arrive back at where we started because 3× 1/(3) = 1

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So here is an actual smart method I can use by mere looking at this

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How about swap positions of powers 1/9 with 3? This will mean that 1/9 × 3 will no longer give us 1. Hence, manipulated

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😈

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How can I do this?

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Commutative property of multiplication

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A×B = B×A

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Upon raising the LHS to (((3)^1/(9))^3)^1/(3) = x^1/(x)

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We get through Commutative property that

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(((3)^3)^1/(9)^1/(3) = x^1/(x)

snow dawn
#

This can be simplified to: 27^1/(27) = x^1/(x)

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The answer is crystal clear

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For the RHS to be equal equal the LHS, x= 27. And this is one answer to the question

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Maybe using different powers will give us other answers Idk I haven't checked

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But I am happy this worked 🙂

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Or maybe this is the only real solution to the problem

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Because any other power will still be equals to 1

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Not changing the skeleton of the equation arriving us at the same answer

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So x = 27 is the only real solution to this equation, algebraicly

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Anyways...

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I have a more intense question

#

In question 7 I struggle to draw the correct graph needed to solve for the equation

#

I was marked incorrect for some reason even upon shading the region that had values in common

#

I don't understand why

shadow schooner
grand pondBOT
snow dawn
#

Here is my working

#

Here is the graph I drew

#

Why is the region shaded the incorrect requirement for the solution?

fallow scarab
snow dawn
shadow schooner
#

yeah new question new channel could be a good idea nonetheless

snow dawn
#

Not too long

#

K

#

.close

midnight plankBOT
#
Channel closed

Closed by @snow dawn

Use .reopen if this was a mistake.

visual tiger
#

it's just the only nice one as I stated

snow dawn
#

You once stated that W is not a number @visual tiger

visual tiger
#

it takes numbers as inputs

#

and outputs other numbers

visual tiger
grand pondBOT
#

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

visual tiger
#

it takes inputs such as 4 and outputs 2 in that instance

#

well

#

W takes inputs

#

and outputs stuff too

snow dawn
#

Oh I see

#

So W is the inverse function of xe^x?

visual tiger
#

so... there is another solution, a number, that can be expressed using the lambert W function

visual tiger
#

in a way

#

just like sqrt(a) chooses to output the positive number such that x^2 = a

#

there are two branches to W lambert function

#

$W_0$ and $W_{-1}$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
#

Why specifically 0 and -1?

#

.reopen

midnight plankBOT
#

visual tiger
#

it's notations, I don't remember why exactly

#

I think it's because the lambert function breaks at -1

#

as -1e^(-1) = -1/e, and it's the turning point of the xe^x function

#

$W_0(a)$ is the only $x\geq -1$ such that $xe^x = a$

$W_{-1}(a)$ is the only $x\leq -1$ such that $xe^x = a$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

and just like we need $a\geq 0$ for $\sqrt a$ to even exist

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

we need $a\geq -\frac 1e$ for $W_0(a)$ to exist

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

and we need $-\frac 1e\leq a < 0$ for $W_{-1}(a)$ to exist

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

W lambert function is much nastier as an inverse function than the square root in that sense

#

but it still fulfills its role as an inverse function

#

so, just to quickly come back to your problem

snow dawn
#

I see that 0 is the minimum value and -1 is the maximum value. They are just connotations

visual tiger
#

so we can finish this actually knowing where the second solution comes from

visual tiger
#

so

#

$3^x = x^9$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

we can rewrite as $x3^{-\frac x9} = 1$ as we did previously

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

$xe^{-\frac x9 \ln 3} = 1$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

we want (something)e^(same thing) = ...

#

so we can apply lambert W

#

so

#

$-\frac x9 \ln 3e^{-\frac x9 \ln 3} = -\frac{\ln 3}{9}$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
#

Where is the Lambert W .-.

visual tiger
#

$-\frac 1e \leq -\frac{\ln 3}{9} < 0$, so there will be two solutions

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

then $Xe^X = -\frac{\ln 3}{9}$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

so $X = W_0\left(-\frac{\ln 3}{9}\right)$ or $X = W_{-1}\left(-\frac{\ln 3}{9}\right)$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
#

The question arises

#

How did you come up with -ln 3/(9)?

visual tiger
#

we remember we want Xe^X = something

#

to apply W lambert

visual tiger
#

and now rearrange by multiplying or dividing

#

to get Xe^X = ...

visual tiger
visual tiger
#

and now solve back to x

#

$-\frac x9 \ln 3 = W_0\left(-\frac{\ln 3}{9}\right)$ or $-\frac x9 \ln 3 = W_{-1}\left(-\frac{\ln 3}{9}\right)$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

$x = -\frac{9}{\ln 3}W_0\left(-\frac{\ln 3}{9}\right)$ or $x = -\frac{9}{\ln 3}W_{-1}\left(-\frac{\ln 3}{9}\right)$

grand pondBOT
#

Raphaelisius Maximus MMIII

snow dawn
#

How did you change 3^x = x⁹ into this?

visual tiger
#

^1/9

#

then divide by 3^(x/9)

#

which is the same as multiplying by 3^(-x/9)

snow dawn
#

Oh

#

Does this always give you an expression like xe^(something), like almost always?

visual tiger
#

that's what we're looking for by design

#

if you have e^(....) = x or something

#

you can simply put the exponential to the other side

#

knowing that it will just carry a minus in the exponent

#

and so you will have (something1)e^(something2) = ...

snow dawn
#

I am guessing this won't be the same for 3^x = 2^2x

#

For this we still have to make it shape to that design

visual tiger
#

this is a different type of equation

#

and actually is easier

#

lambert applies mostly to "x^... = ...^x" types of equations

#

so x acts as both the base of one term and the exponent of another

visual tiger
#

and so this is a matter to be left to logs

snow dawn
#

Oh true

visual tiger
#

$x\ln 3 = 2x\ln 2$

grand pondBOT
#

Raphaelisius Maximus MMIII

visual tiger
#

you'll also find that this is only true for x = 0

snow dawn
#

Ok thank you, I appreciate this lecture 🙂

#

!done

midnight plankBOT
#

If you are done with this channel, please mark your problem as solved by typing .close

snow dawn
#

.solved

midnight plankBOT
#
Channel closed

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Use .reopen if this was a mistake.

midnight plankBOT
#
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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>.
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• 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.

stark verge
#

The quadrilateral ABCD is a parallelogram. The segments AE, BE, CG, and DG intersect the interior angles of the parallelogram.
Prove: Angle BFC=90. I didnt manage to solve this after hours of work.

shell wigeon
#

Do you mean "bisect the interior angles"?

stark verge
#

like ADH HDC are equals FCD and FCB equals etc

shell wigeon
#

Yeah, bisect

#

As in "split in two equal parts"

#

Anyway, AB and CD are parallel, so what's the sum of angles ABF, FBC, BCF, FCD?

stark verge
#

I'm assuming 180, right? Because in a parallelogram, adjacent angles are complementary to 180.

zenith snow
#

And in triangle BFC,the sum of all three angles
<BFC+<FBC+<BCF=?

shell wigeon
#

Yes

#

ABF = FBC and BCF = FCD, as given by the bisectors, so you should be able to find FBC + BCF, and then BFC

midnight plankBOT
#

@stark verge Has your question been resolved?

stark verge
#

thanks

mortal mirage
#

@stark verge you still need help?

midnight plankBOT
#

@stark verge Has your question been resolved?

midnight plankBOT
#
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midnight plankBOT
#
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.

calm shuttle
midnight plankBOT
calm shuttle
#

statistics

#

can someone pls tell me why #24 is wrong

#

26/90 is 0.28888888889

#

rounded to 2 decimal places should be 0.3

#

why does this website say its wrong

#

RF relative frequency is frequency over total so i put 26 over 90

past jay
#

Hmm

#

I'm sure the total amount of men is 99

#

This might have been where you made your mistake

calm shuttle
#

And ur right thank u

#

😭

past jay
#

No worries

calm shuttle
#

but wouldnt the answer still be 0.3?

#

because if i divide 26 by 99 now i get 0.26

past jay
#

2 decimal places

#

So you don't write 0.3

#

You write 0.26

calm shuttle
#

Wait im so confused

#

Why did 0.4 work

#

For the last one

#

Even if it was 1 decimal place

#

And do i not have to round it?

past jay
#

Because it coincidentally is 40/99 = 0.404...

#

So 2 decimal places is 0.40

calm shuttle
#

Ohhh

#

Bye im like slow

#

My bad

#

Thank u tho

past jay
#

Nw

nimble leaf
midnight plankBOT
#

@calm shuttle Has your question been resolved?

midnight plankBOT
#
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#
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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>.
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fierce canyon
#

a person wrote out 10.5^47 as an answer in full as a decimal number, how many digits did she write

mortal falcon
#

hint: 10.5 = (10 + 1/2)

#

hint 2: ||binomial theorem||

fierce canyon
mortal falcon
#

okay you can also do this with logs

#

if you have seen those?

fierce canyon
mortal falcon
#

im stumped breadpensive i think someone else is able to help though

mortal falcon
#

what unit is this for?

fierce canyon
#

from a past paper

modern sapphire
#

the number of digits beyond the decimal points is gonna be the same as the those in 0.5^47, so deffo 47 beyond the decimal point, and 48 before

feral sedge
#

it's not exactly obvious that 1.05^47 is less than 10 (indeed it is 9.90...)

modern sapphire
#

0.5^47 is same as (5/10)^47

#

and 5^47 doesnt have any decimal places

#

so, the whole number gets shifted by 47 places once divided by 10^47

modern sapphire
fierce canyon
feral sedge
#

10.5^47 = 10^47 * 1.05^47

#

so obviously the integer part has either 48 or 49 digits

#

but how do you know it is 48 for sure

modern sapphire
#

oh ic

feral sedge
#

it is extremely unclear

#

at least not without some more specific analysis

fierce canyon
#

how do we find the digits in 1.05^47?

modern sapphire
modern sapphire
#

we can simply prove that the last digit of 5^47 (which is def not 0, coz there is no factor of 2 there) gets moved 47 places after the decimal point

#

and thats the only contributor to the smallest digit

fierce canyon
modern sapphire
#

10^-47 is easy to find no?

fierce canyon
modern sapphire
#

I am talking about $\left(\frac{5}{10}\right) ^{47}$

grand pondBOT
#

Bacter14Fr0g

fierce canyon
modern sapphire
#

5^47 has only 0s in decimal places

#

its an integer

#

so, upon dividing by 10 once, it has 1 non-zero decimal place digit

fierce canyon
modern sapphire
#

once you do it 47 times, that means, it is gonna shift the decimal point 47 places, so that it ends up having 47 digits in its decimal form, beyond the decimal point

modern sapphire
#

no fraction part

#

nothing to the right of the decimal point

#

nothing except zeros

#

it is 710542735760100185871124267578125.000000000000...

fierce canyon
#

oh

#

yeah

modern sapphire
#

once you divide by 10, it becomes 71054273576010018587112426757812.5

#

another division by 10, makes it 7105427357601001858711242675781.25

fierce canyon
#

so it has to be 47 digits from the decimal point once its done 47 times

modern sapphire
#

if you do it 47 times, the last digit 5 ends up in a place of value 10^-47 aka at a place 47 digits beyond the decimal point

fierce canyon
#

@modern sapphire

native prairie
#

Can someone help me with this question? It asks for the sum of f(1)+f(2)+f(3)+...+f(n)

modern sapphire
modern sapphire
midnight plankBOT
# native prairie

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).

fierce canyon
#

@modern sapphire u here rn?

modern sapphire
#

how am I supposed to help you with that

midnight plankBOT
#

@fierce canyon Has your question been resolved?

midnight plankBOT
#

@fierce canyon Has your question been resolved?

midnight plankBOT
#
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#
Available help channel!

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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>.
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last slate
#

Can anyone help pls ive been stuck on this got ages

pearl hull
#

Sure

#

What have you noticed in this question?

#

@last slate

last slate
pearl hull
#

BEC*

last slate
#

O ye mb😭

#

But yh its 90

#

Thats what ive noticed

pearl hull
#

decent ✅

#

Nice find, next question, what information can you get by knowing EDC = 136°

last slate
#

Would EBC be 180-136? =44

pearl hull
#

YES

last slate
#

O

#

Ohhhhh

pearl hull
#

wanna try for 3 minutes before the next hint?

last slate
#

So then ECB is 46?

pearl hull
last slate
#

So now im guessing its uh

#

Something to do with the angles around a point theorem?

#

or two radii?

pearl hull
#

You can actually apply the same technique we did on finding EBC

last slate
#

EAB?

last slate
#

Oh wait is it triangle EDC?

pearl hull
#

It’s another quadrilateral

last slate
#

O

#

So that means

#

ECB + EAB = 180?

#

OHHHHHH

#

SHI

pearl hull
#

Absolutely ✅

last slate
#

SO ITS 134?

#

AYYY TYSMM

pearl hull
#

wtf, what’s 1B?

last slate
#

a question from hell..😭

pearl hull
#

-# Sorry, I’m an Asian and I’m more curious about the mistakes

last slate
last slate
last slate
keen saddle
hushed mauve
keen saddle
#

i use sotrue instead of \s sometimes

hushed mauve
#

i also use KEK for a reason

#

anyway

last slate
#

but uh yeah i have no clue where to start i wish i could use a protractor tho lol

hushed mauve
#

i think i remember there's a theorem that relates the exterior angle of a tangent to something

modern sapphire
#

the circle looks pretty round, so tbf you could get away with using a protractor here

keen saddle
last slate
#

Angle formed whena. Tangent touches circumference = 90?

last slate
#

And plus im on holiday nd didnt bring it😭

modern sapphire
#

it was a joke my guy

keen saddle
#

i think there was a theorem called alternate angle something

last slate
fleet axle
#

i don't get why any others are equal to EGF lol

hushed mauve
#

that only applies if there's a radius

#

but obviously there's none here

last slate
keen saddle
#

maybe that could help

last slate
#

yea

#

but applying it is the dodgy prt

modern sapphire
#

just look at which arc corresponds to the angle

modern sapphire
fleet axle
#

can you explain

#

angle EGF

keen saddle
#

@fleet axle lets focus on vyaas first

fleet axle
#

vyaas asked the same thing though

modern sapphire
#

the tangent at G, and the chord EG also subtend an angle within the circle. All the angles that subtend the same arc/segment would have the same measure

last slate
modern sapphire
#

i have no clue about two radii theorem, do you mean inscribed angle theorem?

last slate
modern sapphire
#

no, I do not

fleet axle
last slate
modern sapphire
last slate
#

So that means both GED and GBE are equal? As bith the chords correspond

modern sapphire
#

GED and GBE dont even subtend the same thing

fleet axle
#

check the order of the letters

modern sapphire
#

maybe you need to check the angles, coz one of the angles is correct, and the other has wrong order of letters

last slate
last slate
modern sapphire
fleet axle
last slate
last slate
modern sapphire
last slate
thorny solstice
#

Hi!

last slate
modern sapphire
last slate
modern sapphire
#

why not CGE?

#

isnt that also connected?

last slate
#

Oh

#

um

#

Shit

#

I acc dont know

fleet axle
#

(this is an active help channel :p)

#

so we wanna find two angles that share the same arc (AB in the above pic)

last slate
#

Wait what

#

Why that one..

last slate
fleet axle
#

ig you're thinking of remembering that property separately and applying it, that's fine too

modern sapphire
last slate
#

Ye

fleet axle
#

well i usually memorize as less as possible

modern sapphire
#

its better to reference to things which make direct sense

last slate
fleet axle
#

i'm not gonna really say one method is better than the other

fleet axle
fleet axle
#

and it's really a recommended way to learn math

last slate
#

im getting so confused now im not even kidding-

modern sapphire
#

well, @last slate back to the problem

fleet axle
#

but it doesn't matter which method is better, you can do whatever you prefer

modern sapphire
#

can you use the theorem in this figure?

last slate
#

AND GDB

modern sapphire
#

again? why are you looking at BG?

#

the question asks for EGF

#

and other angles equal to EGF

last slate
#

Cus of alternate segment

modern sapphire
last slate
modern sapphire
#

GCB becomes equal to BGA

#

which is once again, not what the problem cares about

last slate
#

oh

#

uh

modern sapphire
#

you got this angle you need to care about

last slate
#

Would it be ecg?

fleet axle
#

but that's not what we're after

last slate
modern sapphire
#

tho there are more

last slate
#

Is it ebg as well?

#

OHHH I SEE TYSM

fleet axle
#

any more?

modern sapphire
#

is that all the angles?

last slate
#

ye im pretty sure

#

Cus of the alternate sefment theorem

modern sapphire
fleet axle
fleet axle
#

or just the same logic you used to find the 2nd angle EBG

#

there's one more

#

at least

last slate
#

thought there were 2?

fleet axle
#

well if you can prove there are no more with the alternate segment theorem, maybe

#

bacter asked how you proved it

#

if there is no proof, then there could be more

last slate
#

oh

#

uh

modern sapphire
#

so till now you got

#

is there something that looks like has been ignored till now?

last slate
modern sapphire
#

yes

last slate
#

ohhh

#

So that means BDG is also equal

fleet axle
#

B-D-G?

modern sapphire
#

WHY ARE YOU OBSESSED WITH THE SAME WRONG ANGLE?

fleet axle
#

BDG

last slate
#

But thats in the same segment tho?

modern sapphire
#

and what segment would that be?

fleet axle
#

you mean the angle that has its "corner" at point D? @last slate

last slate
fleet axle
fleet axle
#

so that subtends arc BG, right?

last slate
#

I mean if BCD is equal then since BCD and CGD are in same segment doesnt it make em equal?

modern sapphire
#

I dont think anyone mentioned BCD here at all

last slate
#

..

modern sapphire
#

and also, BCD and CGD are not equal

fleet axle
modern sapphire
#

they have no reason to be equal given the information in the question

last slate
modern sapphire
#

do you sort the letters of the angle in the alphabetical order?

last slate
fleet axle
modern sapphire
last slate
#

Yep

modern sapphire
#

are you sure these are the angles that you meant?

last slate
#

wait lemme check

modern sapphire
#

if so, what segment do they share? pls highlight it in the diagram

last slate
#

Oh

#

They dont

modern sapphire
#

Well, we earlier confirmed that you got the angles EBG and ECG correctly, can you highlight the segment that they share which makes them equal?

fleet axle
#

(you could've applied the theorem if BC was tangent to the circle for example, you might've been thinking that. it's not tho)

fleet axle
#

that looks like a line connecting the "corners" of the two angles but not necessarily a line that they share

modern sapphire
#

sadly, no, that is not the segment

last slate
fleet axle
modern sapphire
#

in circles, the section of a circle made by a chord is considered a segment. So this is the "segment" that they share

fleet axle
#

^ they both "subtend" GE

last slate
#

Oh

#

shi so

#

Does that mean theres only 2 then?

modern sapphire
#

so any angle that is formed with G and E as vertices is gonna be the answer

fleet axle
#

it depends if there are any more angles that subtend GE

modern sapphire
last slate
#

I think ive said GCE

fleet axle
#

yes

modern sapphire
#

ECG is same as GCE which you already said

last slate
#

BED?

modern sapphire
fleet axle
#

spoiler method: ||sometimes math is about finding patterns. the 2 solutions we have are GBE, and GCE. a pattern here is that they both start with G and end with E||

last slate
#

Wait it doesnt have to be a triangle does it?

modern sapphire
#

an angle is not a triangle

last slate
#

O

#

Shivi forgot that

#

So tha means

#

GDE?

modern sapphire
#

yep

last slate
#

Erm

modern sapphire
#

is that all the angles tho?

last slate
#

Either ive pressed the wrong oens

#

fuck

modern sapphire
last slate
#

shit

#

So minor problem

#

That i forgot to account for

#

when you get a question wrong

#

The system changes a little bit around

#

😭😭😭😭😭😭

modern sapphire
#

no wonder you were hyperfocused on that angle 😭

#

you just forgot to tell us that

#

well, back to the same stuff

last slate
#

mb

fleet axle
#

it's the same problem but the picture is flipped horizontally and letters renamed

last slate
modern sapphire
#

are you sure this time it is the same angle? coz its the 3rd time you would be attempting

modern sapphire
#

may be they changed again

last slate
#

Yeah

#

Im not too sure tbh

fleet axle
# last slate huh

i mean when they changed the problem. they just flipped the image and renamed letters
(at least that's one way to view it)

last slate
#

Oh

#

So i can tell that one of em is bcg

fleet axle
#

my point is just that it's the same problem as before

fleet axle
last slate
#

So then the next would be BDG? Because of it subtending b and g

fleet axle
#

yepp

modern sapphire
#

vyaas on fire 🔥

last slate
#

Yeeee

#

hmmm so if there is another one itll be BEG right?

fleet axle
#

yeah that's it 🎉

modern sapphire
#

indeed

last slate
#

Lets seeeee

#

pls work lol

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EYYYY

pearl hull
last slate
fleet axle
last slate
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TYSM @pearl hull @fleet axle @modern sapphire YALL THE BEST

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ty all again ill close dis now🙏🙏

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.close

midnight plankBOT
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Channel closed

Closed by @echo bronze

Use .reopen if this was a mistake.

midnight plankBOT
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viral dagger
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whats the motivation to this?

midnight plankBOT
viral dagger
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like they just let stuff be variables and it just so happens that it creates an equation that grts the question?

lyric charm
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the motivation is that they consider a quantity that can be easily tracked throughout the operations we perform upon these sets

lyric charm
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(k-d)-dn is the net change in the set total

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ie thats what it works out to be

viral dagger
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what about the motivation of completing the cycle

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is it like just a trial and error thinggy

lyric charm
viral dagger
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is it just making it more favourable since if we didnt complete it we would get like k=d(n+1)+n with k=2^n-1 and thats messier?

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ooh wait ok i think i get it now

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thank you!

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.solved

midnight plankBOT
#
Channel closed

Closed by @viral dagger

Use .reopen if this was a mistake.

midnight plankBOT
#
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.

barren wharf