#help-39
1 messages · Page 215 of 1
lol
you got the points right?
just put them on equation of line and they should satisfy the equation
:))
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this is my third time sending this i think
someone help
and give me a answer please
@cedar solar Has your question been resolved?
median means its in the middle. look for which one is in the middle.
im just confused on what class to take
what do i take as median class
you use the class part of the table
because its asking for the median class
also even by looking at the answer choices, you can tell which part of the table you need to use.
median class should be taken as the class having higher value than n/2 or equal and greater than n/2
how
well, look at the choices. and look at the table. which row do you think you would have to use to get the answer?
this a question
for this small of a table you dont need to use a formula you can just find the middle
especially since it has an odd number of values
30-40?
take one off from each side. see what you're left with when you have one value left
take one off from the left and one off from the right. keep crossing it off until you have one value left
the class bro, i already mentioned before that you're using the class values to get the answer
you mentioned you have to find it by frequency. so now rearrange the table so that frequency goes from least to greatest
and then find the median
@flint basalt i believe ur taking the wrong approach here
how so?
10-20
50-60
60-70
70-80
20-30
40-50
30-40
since its a cumulative frequency table we will first need to add all the frequencies and then divide it by two. which in this question gives us 45. and then we see in which class the 45th value stands at which in this question is in the 30-40th class
wouldnt 40-50 give you the 45th value?
please stop sending these here.
wait i might be wrong, lemme solve it again on paper once
class cf
10-20 5
20-30 20
30-40 45
40-50 65
50-40 72
60-70 80
70-80 90
np
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isn't this one also telescoping
oops wrong question
isn't this one also telescoping
tm gave this formula
but how would it work for this one
this series is not telescoping in any neat fashion
it is the sum of two geometric series
how?
It asks for the result of [n = 0, n = 1, n = 2, n = 3] and then for diverging, you'll simply reference large numbers in a series(10, 100, 1000, etc.).
Oops? I guess that's too complicated.
how would i find the sum of the series from that
So hopefully you can recognize that Σ (1/7)ⁿ is geometric. That's rⁿ for some r < 1
P SERIES
Not p series, because the exponent is not a constant
emm okay
My bad. I looked it up: It actually does refer to geometric series. Can I provide an image for aid?
ok
Although I think you could just look up an image on Google, I stole this directly from there for reference:
You have a function, right? :)
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ur name means circumference?
@near pine Has your question been resolved?
😭 whar
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Hello, I have doubts about whether I correctly reduced my 3x3 matrix using the Gauss method.
,rccw
i advice you to put the line starting with a 1 on top
you mean change the second line with the first one?
yes
Ohh I see
I'll remember it for the next reduction, thank you very much for the help!
If you give me 5 minutes I can do it again, it will be less tedious.
done
multiply the numbers by -1 and 2 to get 0 on the first line
It would be multiplying the second line by 2 and the first line by -1
I don't know if I'm making myself clear
well since you swap them its 2*first line and -1*second line
so that you have 2
on first
and -2 on the second
Indeed yes, I do the calculation on the right so that there is a record of it, then I add the result of the first line and the second and they give me the value of 0 at the beginning
the issue here is not the idea but the way you multiply the line
you do 2*L1 which should be 2 2 4 but you calculate it as 2 2 2
OOHHHH
You're right, JAJAJAJA I don't know how I didn't notice it
the final result is 0 0 7
and now you can swap 2nd line and 3rd to end the reduction
yeaaa
It would just be a mistake then, I have to be more careful, as I rush to solve it and I make mistakes with the numbers, it is not the first time that it happens
I have to go more calmly
so to keep in mind :
- try having 1 on top left if it don't imply having horrible things elsewhere
- becareful on line operations
- always recheck twice when starting the gauss method
okey, I will
perfect
you're welcome
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hey guys quick question elementary really but when completing a square what number do you subtract form the equasion
,tex .cts
riemann
alright i was confused on whether I was supposed to subtract b/2 or b/2^2
its b/2^2 right?
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\text{I need some seroious help: I have a sequence }u \text{ defined on N with }u_n=3\text{and for all whole number n:}
\
u_{n+1}=\frac{2}{1+u_n}
\
\text{Then I have the sequence v:}
\
v_n=1-\frac{3}{u_n+2}
\
this would be very painful latex
So now I need to prove that v is geometric (in the form of v(n+1)=q*v(n)
wdym?
sounds like induction
I didn't know how to use the latex bot on the server
look at the expression v(n+1)/v(n). tinker with it somehow
So i typed it out on a random website lol
inshallah it reduces itself down to a constant
<@&268886789983436800>
lol
<@&268886789983436800> scam
My bad
Apparently too many people wanna troll and make their names similar to moderator
let it also be known this guy is a huge loser for setting his name to "im scared of women"
,rccw
I've managed to solve the v(n+1)/v(n) down to there
But just can't find a way to make it simpler
After that I also tried to use a hypotese that q=-0.5 (gotten from calculating v(0)/v(1)), but also got stuck
I tried to get ChatGPT to solve this (I am really stuck lol) but even it won't give me a correct answer
Now I am begining to doubt the question 😭
!nogpt
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
Yeah I know, but was just too stuck :(
induction from here should work
Currently I don't really see how I can simplify the last expression further
factorizing by -1 won't really get me anywhere
don't see where you use induction anywhere
Does induction mean simplify?
Or like using a hypothese to deduce something?
I've tried to continue developing the hypothese (which I suppose is also called induction?), but somehow got the result that un=1?
Which is obviously wrong, but I just can't find out where
@oblique sphinx Has your question been resolved?
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<@&286206848099549185>
expand (x+h)^3
!15m
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ie at pt (2,15) f(x) is 15
@supple fractal Has your question been resolved?
$(x+h)^3=x^3+3x^2h+3xh^2+h^3$
mathisfun
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Posted this earlier but still looking for thoughts - could not find a solution 😦
Hard Game Theory Question:
You are forced to play a game with 44 other players. Each of you are presented with 5 boxes - each labelled 1 through 5. You must place the value on the box inside one of the boxes (eg. you may choose to put 1$ into box 1, or 2$ into box 2). Players have no information on any other players' strategies, or which boxes they played (no collusion).
After everyone places their money in a box, the game master comes in, and takes the box with the most money in it, selecting uniformly at random in the case of ties.
Everyone who's money was not in that box gets their money back. Assuming all players are rational, what is the optimal strategy for this game, and what is your EV?
Is this even solvable w/o numeric methods? I tried using monte carlo as well as multinomial to define a loss function and got ~-0.597 as EV, but there r some flaws in the method i used
@fallow junco Has your question been resolved?
<@&286206848099549185>
@fallow junco Has your question been resolved?
i don't even get the question
Wdym? sorry i can try and clarify
@fallow junco Has your question been resolved?
@latent oasis hi game theory
I'm working maybe when I have a sec
if the game master selects a box 5, does everyone who put their money in box 5 loses it or is it just the player with the specific box he picked?
Everyone who puts their money in box 5 loses it
Wdym? Boxes are shared between players
yeah
No no they all share it
And whichever has the most money gets taken
@fallow junco Have you determined the game master's distribution as a function of the player's distribution? Because that's what I would start with
(Assume all players are playing optimall and thus have the same distribution)
Ive tried looking at the player distribution that makes the game master indifferent to all choices - this was the solution my friend suggested
But (at least to the best of my belief) this isnt the nash equilibrium
Verified it w monte carlo too so unless i messed up my code idt its right
yeah I wouldn't think so either
we want the player to be indifferent
not the game master
What ive thought abt is find the distribution s.t. for any box, the probability the 45 (weighed) votes for each box makes it the majority * ev of box (if it is majority) is indifferent
But idk if that is computable rly
And also the probability dist s.t. if 44 other players play w/ that dist, no matter which pure strategy choice we make we are indifferent in EV
Which is what i used for monte carlo sim
to get the -.597 Ev
shouldn't the distribution for the game master be approximately 60/137 * [1, 1/2, 1/3, 1/4, 1/5] ?
as the number of players approaches infinity
idk if that holds true necessarily
Im not sure if this is true or not but that was my intuition at first too
But at least for 45 case we can see it isnt true
how would the players be indifferent then
sure it's not true for 45
it's true for infinite people though
yeah i did w/ sim
Is the players EV proportional to game masters EV? that would have to be true for this to be the case right
Hmm but ur also playing against other players
it's still zero sum
Im not sure if ur wrong or not haha just thinking out loud
the sum of all money leaving is the money put in
But wouldnt the odds of who wins be more like a multinomial based on the player distribution
rather than just like adding it up and being proportional to the distribution itself
well the EV for all the players is the same
yeah
Wait lets assume infinite players
then ev of playing w ur dist (assuming p1, p2, etc) ~>
0.2(60/137)(1) + 0.2(30/137)(2) + 0.2(20/137)(3) + 0.2(15/137)(4) + 0.2(12/137)(5) = 0.43
but we can deviate to only picking 1 -> 0.2(1)(1) = 0.2 exp loss
wait isn't the expected loss 60/137 ?
Wait wdym
Well the revenue of each box would be 60/137
so hed pick them all equally
bc if u place into box 5, ur putting 5$ into it
Wait am i missing something 😭
idk lol
yeah im confused
sorry I'm multitasking
nah u are so good
dw
thank u so much for the help ive been stuck on this all day 😭
no we don't want the boss to pick them all equally
we want the boss to pick with this distribution #help-39 message
Wait mb i misunderstood what u meant there
so that from the player's perspective the EV of each box is the same
Hmm
So find probability vector s.t. odds 1 is majority is 60/137, 2 is 30/137, etc?
Makes sense
yeah I think so
Lemme try this out rq
(used monte carlo so there may be some leniency here) but seems to not hold true necessarily - EV when everyone plays is -0.97 ish, and when i tried my old strategy against this new one, there was a pretty significant benefit from deviating to the old strategy
hmmm
Used a search algo to minimize MSE between monte-carlo generated vector representing probability boss picks the box for a given strategy vector p vs the vector you gave
Like wdym
We're trying to maximize EV as one individual
when i did this test, i used one person playing with the "baseline" strategy i saw before, and had everyone else playing with the strategy the search algo found
oh I see
And there was a pretty large difference in EV (in favor of the one person)
how was the EV for the new strategy not -60/137 though?
shouldn't it be by construction?
Yeah also confused abt this - will recheck code
I did run this for only 45 players tho fyi
So maybe that makes a huge difference
I don't think it matters actually
the boss's distribution has to be the same for the nth player to be indifferent
Tbh honestly even more confused though -> ur logic seems to make sense and is the same as what I was thinking before w/ the selecting strategy s.t. we generate odds the boss picks the box are proportional to the cost of picking the box
Maybe i just fucked up the code somehow but we'll see

it's inversely proportional to the cost of the box
Yeah srry thats what i meant
S.t. the odds boss picks * cost is indifferent
yeah
Thanks for the help though ❤️ continued running tests and seemed to still hold bad performance
Hopefully will figure it out soon
my guess is that even though the boss picks each box inversely proportion to the boxes' actual value, there is a difference between that and picking it both in respect to that value asw as the expected amt of players picking that
yeah the boss should not be indifferent
or at least there's no reason to think the boss should be
by indifferent u mean picking box 1 with 60/137 etc
right
I mean like
the boss might get a higher EV by changing his strategy but he's obligated by the rules not to
if that makes sense
the boss doesn't get to choose his strategy
does he? the boss just picks greedily whichever gives highest revenue
he has full info
I dont rly see how he could improve on EV past that
yeah i just assumed what u meant is as in
we'd find the strategy s.t. the vector representing odds each is the largest is [60/137, 30/137...]
yeah
w/ respect to values ofc
(ignoring ties)
yeah i just had it sample uniformly in case of tie
not sure how much those matter
Which wouldnt actually occur anyway so
Idt it does
yeah so I don't think it would matter
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help
do you know the cosine rule
yes
but instead of $a^2+b^2-2abcos 30$ use $a^2+b^2+2abcos30$
strizz
yes
can i replace p^2+q^2 with 28
yep
wait
kk
you'll get pq= something write
write p in terms of q using this
then replace it back into $p^2+q^2=28$
strizz
so that it's all in one variable
mhm
$p^2+q^2=28 -- a\
p^2+q^2+2pqcos30 = 52 ---b\
b-a\
2pqcos30 = 24 \
pq =8\sqrt{3} \
p = 8\sqrt{3}/q \
(8\sqrt{3}/q)^2 +q^2 = 28$
WHAY
LOL
oh
strizz
it's solvable from here
where did the 52 come from
from squaring 2sqrt(13)
oh ofc
wait what
when was that suppose to happen
OH SHIT
nonno
miswrite
i copied one line wrong from the one above
ohhh
one secc

@minor tide Has your question been resolved?
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Is this value correct
,rcw
what does this notation mean?
@subtle fulcrum
did you try to write down "the product of all natural numbers from 1 to 100 inclusive"?
@subtle fulcrum tagging you here again so you can find this more easily
Sorry I mean multiplying number 1 to 100
"the product of all natural numbers from 1 to 100 inclusive"
ok right
the correct notation for that is $\prod_{n=1}^{100} n$
Thanks
Ann
and your value for it is wrong.
the factorial of 100 cannot really be written in any neater way than 100! i am afraid
but if you want to know the value "in full"...
,w 100!
it's still a fuckoff big number, with 158 digits
there are less atoms in the universe than this 😭
your number overshoots it by like 40+ orders of magnitude
Thank you sir 🙏🙏🙏🙏🙏🙏🙏🙏🙏 for answer because I am only 13 year old I was just trying sir
don't call me "sir" please.
Sorry so what I call
just my name (Ann) will be perfectly fine.
not really
the best i can offer for multiplying tons of integers together by hand is "group factors of 2 and 5 into 10 and similar easy to calculate numbers"
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Yo
which question do you require help with
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Alright so it's not as much of a problem with one question as it is in general with a variety of similar problems:
say for example, you have 52 cards and you need to pick out 3 cards one after the other from the deck without replacement, what would be the probability that you'd get 2 red cards and 1 black card?
I tried this problem in two ways:
- I used the multiplication theorem of probabilities and did (26/52)×(25/51)×(26/50), using this I got the correct answer.
- I did (26C2×26C1)÷52C3, from this method I got basically the above answer multiplied by 3. I don't know what the error is and any help would be greatly appreciated.
do you want two reds and one black in that order?
or is e.g. red-black-red also OK for your purposes? @limpid python
in that case 2) is actually the right answer
yeah I was thinking that as well, but at the same time 1) was given to be the correct answer which had me confused
what's the problem with the first method in that case?
given by whom?
can you show the problem exactly as stated? it sounds like there might be a minor detail getting lost in translation here.
Alright give me a minute
(26/52)×(26/51)×(25/50) red-black-red order
It's working on assumption that you picked them in order.
ok so the way they're solving it
Not necessarily though, whatever order you pick them you'll get the same expression
they do in fact imply that they want red-red-black in that order
or wait no
red-black-red
but if you did not care about order you'd need to consider all 3 possible orders anyway (RRB, RBR, BRR)
and this would give you the same answer as your method 2
wouldn't those orders be considered in the probabilities themselves?
like, if we take a smaller example of 6 cards where 3 are red and 3 are black, and we have to pick 2 cards where 1 has to be Black and another has to be Red
the solution manual says unambiguously: first red, second black, third red
they consider only this draw order to be valid, and not the two others
The probability for:
RRB RBR BRR
Versus the probabilities of:
RRR RBB BBR BRB BBB
The fact that the cards aren't being replaced, could it have something to do with not counting the other draw orders?
your probability in (1) has the specific of RBR
if it was purely the probability of drawing 2 reds 1 black without any order
then you have RRB, RBR and BRR, all of which have the same probability
so you get 3 times it
as found in (2)
okay, I guess it's just an error on the book's part
Thank you all for helping out 😄
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I did not understand how did they solve this.
Topic: Analysis of Variance Tests ANOVA
@midnight haven Has your question been resolved?
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@midnight haven Has your question been resolved?
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dont spam helpers, just wait for someone to respond
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This feels like cobwebs(for me!) from a few years back but I'll ask about what you have thought about so far.
You want to fill this table so you can show your working to compute F and do the hypothesis test for the equality of the means, the critical value for the test can be found in a table like the one I just sent. You reject equality of the means if the F > critical value.
To fill the table you use formulas like $SS_{total} = \sum_{i=1}^k \sum_{j=1}^{n_i} (y_{ij} - \bar{y})^2$
$k$ is the number of groups, $n_i$ the number of observation per group, $y_{ij}$ the value of the observation $j$ in group $i$ and $\bar{y}$ the mean of all the observations
you should have these formula somewhere in your notes
i was told before to not ping them so thats why i said that mb
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explain which vectors are considered equivalent by this distance function
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hello
is the answer here not wrong?
reflection over y axis means the negative in front should be inside right?
is the answer not showing a reflection in x axis?
Yes, for a reflection across the y-axis, the negative sign should be inside the radical.
ok so the book is wrong right?
Yes.
does that mean the graph is also wrong?
Either the answer is wrong or there was a typo and the question should say x-axis rather than y -axis.
Yes, the graph would also be wrong.
ohh ok
Send an email to the publisher.
this book has so many mistakes its really annoying
thank you so much for ur help
yea
They love getting corrections and could very likely acknowledge you in the next edition. 😉
You as well.
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I don’t understand how to do this, I don’t know what to do with the info given…can someone explain this in simple terms? I’m lowkey struggling with summation
Do you know what a Riemann sum is?
yeah its the area usign rectangle
State the relationship between a definite integral and a Riemann sum
um its the number of recntangles as the limit goes on
like the integral splits the area using recntangles
then u add the recntabgles up
Hmm.
thas what my teacher say
$\int_a^b f(x)dx=\lim_{n\to\infty}\sum_{k=1}^n\Delta xf(a+\Delta x\cdot k)$, where $\Delta x=\frac{b-a}{n}$
mathisfun
he told me to use this one example from earlier, but idk how to use it
can i show ?
yeah its this. formul but a little different
it is f(ci)delta x
Yes
So you can sum here
but i dont understand how to use this for that proble m
$\int_0^2 f(x)dx=\lim_{n\to\infty}\frac{2(n+1)(3n+2)}{n^2}$
mathisfun
Yes
okay wait can i try to do it and then send it here to see if im doing it right
wait
the numerato would be 6n^2+10n+4/n^2
cant i just use that limit rule
since 6n^2/n^2 = 6/1 so its 6?
Yes
so whenever i get something like this
i only have to multyply the top out
look for big exponent and use that one limit rule ?
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um
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Exercise 21. (0–3 points)
Paul cut out a right-angled triangle ABC from cardboard, with legs measuring 12 cm and 16 cm (drawing I). Then, he connected the midpoints of the longer leg and the hypotenuse with a dashed line parallel to the shorter leg and cut triangle ABC along this line into two figures. He then rearranged these figures to form trapezoid PRST (Drawing II).
Calculate the difference between the perimeters of triangle ABC and trapezoid PRST. Show your calculations.
T is 16 cm
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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
Hint: || Review Mid Point theory ||
@full prism Has your question been resolved?
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Hello
Is it this one?
Y
What does it mean? A yes?
@full prism Has your question been resolved?
@full prism Please share the problem you need help with
@full prism Has your question been resolved?
Exercise 21. (0–3 points)
Paul cut out a right-angled triangle ABC from cardboard, with legs measuring 12 cm and 16 cm (drawing I). Then, he connected the midpoints of the longer leg and the hypotenuse with a dashed line parallel to the shorter leg and cut triangle ABC along this line into two figures. He then rearranged these figures to form trapezoid PRST (Drawing II).
Calculate the difference between the perimeters of triangle ABC and trapezoid PRST. Show your calculations.
Original question 👆
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im stuck at log(a^5 b)^1/2
because where i would make it 5 log a normally now theres also that 1/2
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I dont understand how to do the second part of this question (Find x and p so that Ax = p is the best approximation to b in C(A).
This is my work for the first part of the question
I'm unsure where to go from there
you can use the normal equation to find the least-squares solution
am i doing this correctly?
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Does this look right?
Oh uh... I cropped the original problem
what you have looks correct
but I think sin is bounded by -1 and 1 if the original problem doesn't specify anything
because the range of sin(x) is -1 <= y <= 1
Yeah, idk why I choose 2
alg but I would use -1 and 1 if you have to submit this for an assignment
will do, thanks!
anytime 🙂
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how do you do this problem
like theres only y we can plug in no x
and theres multiple like "slopes" for every y
if you look closely, at every fixed y the slopes appear to be the same for all x
for example these are all the same slope
in the circle
and the same goes for every "row"
yeah youd plug in 5 for y and the x coordinate wouldnt matter
what is it
the slopes all seem pretty steep. in (b) and (c) at y=1 for example, the run is greater than the rise. but in the graph at y=1 the rise seems much greater than the run
x is relevant if it weren't a multiple choice question lol
the derivatives are all functions of y
do you know how to find the avg value of a function over an interval?
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This approach could work, but proving that U is finite-dimensional actually turns out to be rather hard here
A better approach could be to essentially 'build' a basis for U, starting with an empty set of vectors and adding independent vectors to the set until it spans U; This process must eventually stop, since the size of the set can never grow larger than dim(V)
As far as I can tell, the approach I gave is the best, at least assuming we're working from the ground up
If you mean the "set can never grow larger than dim(V)", that part is trivial since a set of size, for example, dim(V)+1 could not possibly be independent in V
the reason the process stops relies on the fact that an independent set is no longer than a spanning set, and this itself takes some time to prove
sure, i usually phrase it as if v1..vk are independent in V and u1..uj span V then k<=j
the strategy here is already given by 823
you make a recursive process for building an independent set in U
yeah quite a few preliminary facts about independence and span (in finite dim spaces) can be proven by recursive processes, its very neat
you should justify with one line why the new set is independent
also its not clear why the process stops
maybe youre trying to invoke this but not clearly
if v1..vk are independent in V and u1..uj span V then k<=j
ill rephrase the fact as "an independent set is no longer than a spanning set"
so i'd say the process ends as n=dimV (any spanning set of V has size n) and by the above fact we cannot build an independent set longer than n
no prob
823 gave you the strat
more recusion
but if you mean easily
then the book already gave a very short proof
you can prove 2.46 directly using recursion (and my fact)
or prove 2.45 using my fact then use 2.45 to prove 2.46
yeah recursion is probably the ONLY way for 2.40
induction might work
i never bothered bc the recusive algo appealed so much to me
yes
fortunately my prof didnt use LADR and fully developed determinants in lecture
its one of the few crap that properly develops it
his lecture notes
he started at postulating properties of an "oriented volume" function
and showed a construction of the function and how it led to determinants
i attribute my fortune to my prof's physics oriented mind
i had the same prof for my dynamical systems course
books have wide variety of quality
some do that and some just do definition lemma theorem repeat
bourbaki algebra
this book will kill u with dryness
its simply that bourbaki books arent intended for undergrads
(btw bourbaki refers to a group of authors, its a fun rabbit hole if u have time)
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np
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sorry locke
^^ am I supposed to find the equations for f(x) and g(x) based on the graphs before starting the problem?
so for a.
P’(2) would be product rule, so g(2)f’(2) + f(2)g’(2) ?
Right.
but won’t that just be zero?
derivative of any number is zero/ I see that g(x) is zero at x = 2
I am walking through the dark here
No, that's not the derivative of 2.
That's the derivative of f(x) at x = 2 and the derivative of g(x) at x = 2.
f(x) is not 2. g(x) is not 2.
oh wait
It's like if f(x) = x^2.
f'(x) = 2x.
f'(2) = 2(2) = 4.
You only get zero with something like this:
q(x) = 10, so q'(x) = 0, so q'(2) = 0.
You're differentiating f(x), and then filling in 2 for x.
Or you're differentiating q(x), and then filling in 2 for x.
With f, the derivative becomes 2x and then you fill in 2 for x.
With q, the derivative becomes 0 and then you fill in 2 for x.
So, it's the differentiation step that can give you zero, not the argument to f' or q'.
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Yes, that looks good.
No problem.
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None of these match
I am confused
I tried solving it by hand and none made sense either
you may need to change the zoom to match the zoom shown in the charts
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Yes
is there a better way to solve this crap other than using the reduction formula
Probably is with trig identities and stuff, but I doubt any of it will be less annoying than reduction
you can use demoivre for them to get some binomial expansion
which you can then get cos^n in the form of multiple angles of cos
then integral each term like that
so z = cos theta + i sin theta
(by demoive), z^-1 = cos theta - i sin theta
then 2 cos theta = (z^1 + z^-1)
then you can raise that up to the power of n and its all good
im not sure if it could work with negative powers
RHS expansion wont work though for negative powers to get it cleanly
@raven geode Has your question been resolved?
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scared to continue this problem. I need a helping hand.
Positive slope means positive y values
true.
I will adjust that
actually
i’ll fill it out best I can
and return shortly
@woven garnet
please tell me
it was a noble effort
worry not
if it looks linear
the derivative is a straight horizontal line
if it looks parabolic, the derivative is a straight line with slope depending on concavity
which is what I did :3
the sketch of dy/dx h(x)
your solution is wrong due to the parabolas since you made the parabolic derivative discontinuous
they are continous and a singular straight line
my solution?
and are you saying that if
f(x) is continuous then f’(x) must be as well?
the parabola on the left is 1/2x^2 ain’t it?
uh?
that just means that the slope is zero at that point
not a total zero 💔
or a discontinuity
look here's a similar graph with the same zeroes
this expands to some quadratic polynomial
oop
if you take it's derivative
you'll notice that is a continuous straight line
because the derivative is continuous!!!
for a parabola
@sour sluice
ok ok I got schooled
so just redo the quadratic intervals
working on it
and btw the last interval is
sinusoidal
so it's derivative is also sinusoidal
that really sucks ngl.
this means that
the base equation is like
degree three polynomial?
dw the derivative is just that function but shifted by half cycle
no it's a sinusoidal equation
what makes it sinusoidal?
y=Asin(wt+phi)
same amplitude of turning points
so uhm try again for the parabolic and the sinusoidal interval
happy mathing
for the sinusoidal…
will it be inverted in the graph of f’(x)
inverted?
yeah
don't think too hard, just shift it by quarter cycle
like what would the derivative of an unknown sinusoidal function look like?
quarter cycle difference
in periodicity
then just look at the tangent at that point
and find out the initial slope at the start of the interval
kinda alrighht but
the function is at the half ofthe cycle at the start of the interval
so it should not be taking a maxima at that point
@sour sluice Has your question been resolved?
yeah I think I see what you mean. as far as everything else, look ok?
and should I put open circles anywhere else, such as at x=-1
and x=-7
myabe yeah
maybe?
<@&286206848099549185>
tldr- close to finishing this problem
verification on last two images (f(x) and f’(x)) needed
yes, since the derivatives don't equal at those points
guys help me with my MIT integral math homework question(idk how)
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given that A is a point on fx and B is a point on the line y, find the minimal value of AB if AB is vertical to the line y
ive tried using the formula of the distance between a line and a dot, and that the product of their slopes should be equal to -1 and that didn't help
i dont think youd need this
youre given the slope of the minimal line
so you should also know the slope of both functions an the intersection of them and AB
is that enough of a hint?
so i need to do
f'(x) = -1?
no
wait am i right
then its not
even easier
you have the formula for the minimal distance line
just find th.
the intersection with f directly
then you can use the distance formula
@lunar bone hopefully that seems a little easier
I still didnt understand how?
With the derivative?
no
you know the slope of AB
and you know a point
so you can use point slope to get the formula of AB
at which point its just algebra to find the intersection between f and AB (there might be more than one)
What point do i know???
oh my bad, i thought you were given B
@lunar bone Has your question been resolved?
To expand on what jan niku said, since you know that the distance AB is minimum, AB must be normal to the curve, or a line perpendicular to AB is tangent at A (which makes it parallel to y = x-3).
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can anyone help me
take the derevative of V = (pir^2((2025-r^2))^0.5)/3
