#help-0
1 messages · Page 490 of 1
no sadly not
explain what u fail to understand
why that counts
elaborate more
well uhm how can |x-1| / |x+1| <e <=> |x-1| < e . 2|x+1| cuz this is not always true right?
wait actually i think it is
lmfao u trippin or what?
1/2 < 3 <=> 1 < 6 not always true?
ye okay
try to understand why this is true
aaah okay now i get it
@warm quarry Has your question been resolved?
<@&286206848099549185> can someone check if this is correct?
Why you have two accounts 😭
cuz when i am at uni i can quickly swap from devices
Are you trying to find radius of convergence 😐
the what what
Wait this doesn’t look like calc 😭
it is :-:
Oh sorry I’m not the right person idk what min is
oh okay no worries
What math is this
I’m taking that later this yr 
i am in my first year of uni
Oh im still in hs lol
that should be more complicated than this
noooo definitely not
I’ll be there later this year as I said 😭
Hmm odes then?
Idk it is called analyse in the netherlands
but i thought it is calculus
cuz we use a calculus book
🗿
min{1,e} means if e is greater than 1 then it will give the output 1 if e is smaller than 1 then it will give the output of e
Trex can you help him 😭
Does your book ask you to prove theorems (not epsilon delta results for individual problems)?
Or does it just state the theorems?
What stuff?
mostly with limits and continous and closed open intervals
OK, so your proofs are just proving the answers to particular limits?
but this cant be analyse already right
ye for now yes
Analysis
Who is the author of your textbook?
stewart
Which of these: https://www.stewartcalculus.com/?
So it’s kinda like real analysis
OK, if it says early transcendentals, then it's probably a basic calculus course, not analysis.
Oh.
that was in first semester
wait it does say it
mb mb
but can someone check my answer :-:
.
Yeah, that's just for calculus, not analysis.
ye bro i am too stupid for analysis
It looks like your first line that starts with for all is wrong.
Oh huh why
It should be forall epsilon > 0 there exists delta > 0 such that 0 < |x - 3| < delta -> 0 < |f(x) - 15| < epsilon.
(\forall \epsilon > 0 \ \exists \delta > 0: 0 < |x - 3| < \delta \to 0 < |f(x) - 15| < \epsilon)
Chai T. Rex
ye wth
whattt
i am so confused
my professor been doing it wrong for 2 weeks now then
HUH
You don't just write a proposition followed by another.
so it is correct?
It looks like it's written in natural language.
Like this is true for all xs where ....
But that's just <-.
-> already handles the for all part in their statements.
aaah okay
If it's P -> Q, then if P is false, it doesn't count against it being true. So, P -> Q only looks at when P is true.
ye true
What does it say on the 6th line on your proof?
proof delta = {1,e} works for all x
No, I mean "<=> |x - 3| < epsilon" or something like that.
There's something under the epsilon.
Sorry, I need to take a break.
no worries
@warm quarry Has your question been resolved?
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poor kid was asking about trig earlier today and got their account compromised
Sad to see a fellow algebraic geometrician succumb to such things huh
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can someone try to find these answers
does any of the reason say "given"?
yep
ok, so what info is given to you?
that ac is perpendicular to bd
yeah thats probably the first box if its one of the options
but is anything else given?
its in the ss
you know what the tickmarks mean on ad and dc right
theyre congruent?
yeah, so thats another given
i just dont get like what step i'd put it on and everything
you put the given info on the top box
so those top two boxes i should put those two givens
yes
for the very first one, put that ad is congruent to dc
yes, now what do you know about perpendicular segments
they make right angles???
yes, but what are the right angles of the triangle
adc bdc
bdc isa right angle but adc is a straight angle
if you know what linear pairs are, bdc and what other angle form a linear pair?
Oh i see
Is math induction important to study or not?
so you know that adb and bdc are right angles, so what is the reason
linear pair?
anyone?
well i was using linear pair as an example, so that probaby isnt a choice
whats another reason?
perp lines make right angles
yep, or another way to say is "Definition of perpendicular lines"
so thats the third box
Ok, so lets think about abd and cbd as triangles, as they split them up. is there anything they have in common?
yep you got it
okay so last two boxes
ok, can i see the statement options for the box on the very right
those statements are using x and y? thats weird
well id plug in whatever letters
yeah
so what congruence postulate proves that the triangles are congruent
with the info we have
SAS??
yep
it says somethings wrong
wait
deos it say what
it just says ur wrong try again
the box on the righr isnt even necessary.. but i did forget something
its the HL theorem
so just HL instead of SAS and keep the box on the right
ik the box on the right feels redudant which makes me think its wrong
im not sure if you should keep it, or do something like adb and cdb are 90 degrees
you should prolly ask your teacher
cause that last box is just holding us back lol
my teacher never responds till like a week later
u seem smart tho could u help me with a proof that doesnt have a flow chart and is just wtv u want
i tried this for so long like genuinely hours
ok well if a segment bisects another segment, what does it do?
technically the figure is a parallelogram, so they may be called diagonals too
well do u know what segment bisectors are?
yes
ok, what is it
yeah, a bisector splits either a segment or angle in half
so if ac bisects bd, then ?? is congruent to ??? and ??is congruent to ??_
ae ec and be ed
yep. so once we find that those statements are true, then we are done
but it isnt proven that their bisectors yet??
Well, if we do find out that ae is congruent to ec and be is congruent to ed, then we are done. thats our main objective. not sure if theres an option that says its not possible, but most of the time it is possible
its possible
ok, think about how we proved 2 triangles are congruent. if two triangles are congruent, their corresponding sides are congruent (CPCTC). go step by step in order and try to see if you can figure out if be is congruent to ed, and ae is congruent to ec. use paper if needed because you will need to mark yourfigure with tickmarks or the symbol that show that an angle is congruent to another angle
think about aas, asa, sas, etc
i gtg to sleep, but you can ask other ppl for elp
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you know you can calculate it using geometry right?
for the first part and third yeah you calculte the 2 triangles using geometry
but i was talking about the semi circle specifically
oh
well yes for geometry but i didnt know the formula to use
area of cirlce is pir^2
yeah
what is the radius of the circle in the graph
yeah
i always mix the two up
also you need to see that the integration would be negative
as well
so it is negative the area of the semi-circle
may be just right
-18pi
that was right
thats so stupid
lmfoa
one quick quick question
LoL
they should at least put a margin of 1% error
I was breaking this up into shapes
[9,15], i made into a triangle
[15,21] i made into a triangle
[21,27] i made the lower half into a triangle
[ 21,27] i made the upper half a sqaure
you realize that
integration from 0 to 21 = integration from 0 to 15 + integration from 15 to 21
oh wait
i saw that as 0 not 9
i was thinking the same thing
would make sense to do it that way, or write the question that way
but we gotta be difficult
ok how did you get taht the area from 9 to 21
is -45
uno
I think with just by looking you would realize it is 0
realizing that now
anywhere
i got ahead of myself
last questiont hen im off
We've done step four before in class, I did a problem just like this one below this also
I've just never done it with a square root
,rotate
so you used the formula and it was wrong?
I'm unsure of how to get the right endpoints iwth this is all
This is the question I solved that was similar, but it doesnt ask for right end points
isn't the ith end point here supposed to be the right endpoint?
@zenith flax Has your question been resolved?
i did try that and it didnt work lol
oh that is because in riemann sum you don't just sum the result of f(x) at the endpoints
you also multiply the width of each interval by the value inside
so it should be
$$\frac{2}{n} \sqrt{3+(1+\frac{2i}{n})^2}$$
Sherif Player

that is so damn stupid of me lmfao
I added the first two answers together, and got the area of the last shape (triangle).
36+(-18pi)+(1/2(3)(3))
don't evaluate it numerically
ah
just put it in terms of pi
thank you
no problem
.close
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Erm
Help
What does the set notation mean
Like the x>_ 4 thing
Move the lil line over a bit
x is larger than or equal to 4
So it’s not true right cuz the graph goes into negative infinity
it's not true yeah but what do you mean by the graph goes into -inf ?
yep but also in the +inf direction too
Yeah
It doesn’t mention the -inf part
Wait what
yeah
Wait errr what is going on sob
x>=4 is just like [4,inf)
Yeah
But doesn’t that mean the graph starts on the point 4
Not going (inf, inf)
Wait no
(-inf, inf)
yeah the graph is defined for all x and maps all the y values
nod
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<@&268886789983436800>
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nobody gets a fair trial anymore
Sending the link to an nsfw server in a math server is.. a choice
what happened
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suppose $x_1,x_2,x_3,\dots,x_{2025}$ are positive integers such that $x_1+x_2+x_3+\dots+x_{2025}=x_1x_2x_3\dots x_{2025}$, find the maximum of $x_1+x_2+\dots+x_{2025}$
skissue.in.a.teacup
by logic most of x would be 1, as else the rhs would be much much higher
yeah that was my only logic :shrug: guessing around gave me x_(1 to 2023)=1, x_2024=2, x_2025=2025
I'm not convinced that there arent for example two of the numbers somewhere around sqrt(2025)=45 so that the sum is still near 2025 but the product also is roughly 2025
or similar for cube or bigger roots
tho I suppose that wont be relevant if you only want the max of the sum
what
Nothing I am just new in this channel
Solving question entertain me so I joined the channel 😺
but like, if so lhs would be like around 2025+90 but my guessing strat got 4050
which is why I wrote this
i mean the max of the sum is still equal to the product so you can reword it as the max of the product
=> x_1 x_2 ... x_2024 ≤ 2025 ≤ x_2 ... x_2025
This sets a restriction for x_i's```
@raw jetty Has your question been resolved?
In the first place, you do not necessarily have to bug with such a terrifying looking problem:
=> x_2012 ... x_2024 ≥ 2^{11} = 2048
=> x_1 ... x_2024 ≥ 2048 which does not satisfy the restriction```
So essentially, this problem simplifies by plugging x_1 = x_2 = ... = x_2012 = 1
You can similarly do for:
=> x_2013 till x_2018 are ≤ 2```
You don't need to go higher actually :p Assume all 6 of them are 2s
=> (2^6k - 1)x_2025 = 2012 + 12 + ... + x_2024 ≤ 2024 + 8x_2025
=> (64k - 9)x_2025 ≤ 2024
=> x_2025 ≤ 2024/(64k - 9), where k = x_2019 * x_2020 * ... * x_2024 ≥ 2^6
so not all of them can be 2s either```
Can you use the same idea and show none of them can in fact be 2s?
Another hint :p you can totally use that x_2025 = 2025, x_2024 = 2, all other x_is = 1 is a solution
Here's how I'd proceed.
=> x_2025(2x_2024 - 1) = 2022 + 2 + x_2024 ≤ 2024 + x_2025
=> x_2025(x_2024 - 1) ≤ 1012, where x_2024 ≥ 2
=> x_2025 ≤ 1012
=> (x_1 + x_2 + ... + x_2024 + x_2025)_{max} = 2022 + 2 + 1012 + 1012 = 4048
Since this falls shorts of 4050, x_2023 must also be 1```
the rest can be solved as such: 2024 = (a - 1)(b - 1) => (a + b)max happens at a = 2025, b = 2
=> 4050 is indeed the best maximum we can find
wait so the max is 4050?
It'd appear so
sorry toom a shower
toom
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Let f:ℝ→ℝ, f(x)=ax+b, a,b∈ℝ, a≠0.
Show that there is an x₀∈ℝ\ℚ such that f(x₀)∈ℝ\ℚ
are you allowed to use arguments about cardinality?
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can someone help me construct the pmf on the letter B
@gaunt turret Has your question been resolved?
<@&286206848099549185>
What does the sum of the seven spot mean
1+6 or you get 7 different face on the 2 dice
The former. So 1+6, 2+5 etc
So like you roll both dice and get 7
I don't know about pmf
But the probability of getting 7 by rolling 2 individual dice is 1/6
6/36
probability mass functionn
it's like the table
x and P(X=x)
The way to construct them that I don't understand
@gaunt turret first think of the values that x can take
yes. any idea?
Go to a new channel
ok
@gaunt turret
1-6?
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So how do I go about solving this equation
I have a exam on it in 3 weeks and I have no idea how to do it at all I was out
start with plugging u_n = v_n + k, k constant
after rewriting in terms of v_n, you can choose the value of "k" such that the equation has no constant terms
sorry u_n=v_n + k ?
yes make that substitution
so everywhere you see u of something replace it with v of that same thing and then add k
$u_n = v_n + k$
Arya
Substitute this into your eqn.
Yes
because v_n is also a function of u_n, so yes... if you change n on the LHS, n on RHS changes as well
ahh ok
You're in the process of homogenizing it
thankss alright ima do what i can and send a pic of where im at
,texsp $v_{n+2} - 2v_{n+1} - 35v_n = 144 + 36k = 0$ for $k = -4$
Arya
let me know when you have this
$v{n+2}+k - 2v{n+1}+k - 35v_n+k = 144$
maT
i did it wrong
Arya
im charging my phone so Ill be able to send pics but I dk how to use the formatting for the maths thing
so the -2 affects the k aswell?
Yes it does. it is multiplied to u_{n+1}
so when substituting, it multiplies with everything u_{n+1} is
ohhh so also for the -35?
and a + 1
yess i got it now
and remind me why do we let it equal to 0 and solve for k to get -4
scratch your second line, that's bs
yup done
you need to delete the constant term from the fourth line so you have a homogenous equation that you're familiar with
plug k = -4 to get rid of 144 + 36k. Can you solve the rest homogenous eqn?
@vital ocean Has your question been resolved?
@vital ocean Has your question been resolved?
.close
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The question Down and first this queston is <0 right?
Or not 🤔 it's >5
yes its smaller than 0
Yup I'm right ty
I can't get do questions like Multiplication of fractions but i can do logarithmic and trigonometry lol :@@
nice theyre teaching you what they taught me last week
What about this down 3😭
Which language is this?
Georgia
I see
😅😆
down 3?
what is the question even asking ?
Compare the value to 0.
that should probably be $\log_{\blue{a}^2 + 2}(a^2 + 1)$
hayley, who shakes the world
Yup
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someone solve the integral please
Why wouldn't someone not like to solve this cute integral?
Consider || z^2 = 1-sqrt(x) ||
cool thank you
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why is it wrong i put it in a graph and its wrong😭
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
i made this problem so this is it
It's just more efficient if we know what you're trying to do
Instead of piecing it together from your work
i want a quadratic function (opening downwards) that has the tangent 2 (so going through P(10|5) and Q(11|7)) and i want it to be 25 up
A quadratic function has variable tangent.
Do you mean it must be passing through some point and has a tangent 2 at that point?
is tangent the same as gradiant?
yeah
what are the coordinates
P(10|5) and Q(11|7)
just so you know, if the curve for the quadratic function passes through 2 points, the line joining them is not tangent to the curve
so if you want the function to pass through these two points, it'll simply be a quadratic function that passes through two given points
yes
.
the way to find this is to write $\frac{1}{a} = \frac{(x - h)^2}{f(x) - 25}$
Arya
Passing it through the two points gives you
$\frac{(10 - h)^2}{5 - 25} = \frac{(11 - h)^2}{7 - 25}$
Arya
did you solve this?
looks like you did.
Let me verify your roots rq
okok
,w 10(11-x)^2 - 9(10 - x)^2 = 0
You got one of them right, you missed h_2 = 20 - √90
right, I had it cropped so I didn't notice
youre good
let me verify your "a"
You're bad ._>
You missed the exponent in the denominator
oh
hm
btw you might want to rationalize your denominators, plugging that ugly "a" into your quadratic form would displease whoever you're trying to show this equation
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ok so
No
it works yea
a little overcomplicated but it works
put a bracket in 1/(4a)
yes ty!
can u tell me the quicker way?
b = -4ac/(3*(4*a - 1))
is the cleaner way to say it
they are the same mathematically
you can, if you wish, replace each side with 1 / that side
the result would be $p = \f1{\f1q + \f1r}$
hayley, who shakes the world
i see
i don't think you want to do that
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Double angle formula
okay i just googled what that was and that would change the numerator into 2sinxcosx right?
it would turn into this
is the next step to distribute? then integrate? or is 5/4 a constant that i can pull our before i integrate?
Cancel
Yes you can pull out 5/4 as well
cancel the sinx from top and bottom?
yes
wait a minute thats illegal

wait what?
$\int \frac{5\sin 2x}{4\sin x} \dd x \neq \int \frac{5\cancel{\sin} 2\cancel{x}}{4\cancel{\sin x}} \dd x$
Arya
kill it with fire

proceed with what you were doing
XD
Anyways, yes. Double angle formula of sin 2x and cancel the sin x
is this right or not?
No no, the sin x got cancelled, why is that still there
"cancelling" meaning that you remove from both the numerator and denominator
yeah, better
okay now i integrate?
$\frac54\cdot 2=\frac{5}{\cancel{4}^2}\cdot\cancel{2}$
;(
yep
this is not 4^2 btw it means 4 reduces to 2
okay so i take out the 2 before integrating
yes
gg ez
yay thank u!
yw
check for any mispellings
hell, it took 3hrs for me to realize a mistake on the other thread
alright let me work it out
$\int\frac{5\sin(2x)}{4\sin(x)}dx=\frac54\int\frac{2\sin(x)\cos(x)}{\sin(x)}dx=\frac52\int\cos(x)dx=-\frac52\sin(x)+C$
;(
umm i can type it into symbolab
im just traumatized from the other thread 
$\int \frac{5 sin(2x)}{4 sin(x)} dx = \frac{5}{4} \int \frac{2sin(x)cos(x)}{sinx} dx = \frac{5}{2} \int cos(x) dx = \frac{5}{2} sin(x) + C$
kronium_
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dont ask for help on a test
do you think cursing at somebody makes them inclined to help
please dont...beg.
what makes anyone think thats a test
so...do you wanna show your work, or...?
,w (63.8 *(sin 58.5°))/(sin 99.5°)
thats fine
calculator error :p
b = (63.8)(sin 58.5)/sin(99.5) right?
does mathway work
sure
i got 55.15
,w (63.8)(sin 58.5°)/sin(99.5°)
wtf
then why'd you write 54.8 in your hw lol
solve similarly for c and lmk what you get
this one that you did
bring c to the left and every other thing to the right
iu put this in
to the caluclator
and got 55.15
why'd you put that.. that was the equation for "b"
o shi
To get "c" you solve the equation for "c"
Lol aren't you past your 5 min deadline
No Peter ._> Ask Louis
what
jk go ahead
solve
i dont understand
$\cos \angle A = \frac{AB^2 + AC^2 - BC^2}{2\cdot AB \cdot AC}$
c
2
=a
2
+b
2
−2ab⋅cos(C
Arya
ik thats the law
plug everything you have into this to get BC
ok gimme a min to do that
does solving triangle means you also ought to find the remaining angles? 
uh
le mme see
im p sure we only need one row
how do i plug this in mathway is not working
use wolframalpha
oh type shit
:p
Lmao gotta trust your hands on this one >.<
$BC = \sqrt{AB^2 + AC^2 - 2\cdot AB \cdot AC \cos \angle A}$
idk how to do this either
Arya
you missed a square root
the thing you wrote on the right side is BC² not BC
Which part you don't understand
everything
you wrote the cosine law right
you need to replace "bc" with a variable
the calc is reading B, C as seperate variables probably
Bc is not b*c it's is the length from point b to point c
is why I used BC = x
cosine law only gives the value for a side, in this case BC, given that you have 2 sides and including angle
Angle b or line BC
Now you gotta use sine law for the remaining angles b and c
angle b
Then the formula slightly changes but still the same
Cos(a) = (BA^2+CA^2-BC^2)/2BA*CA
brah
I dont think this is the right formula because we use side a,b,c not point a,b,c
Let me revise it
Just input the length
wdym
For example we want to find angle c
yes
yes
We add the square of them
Then divide it by the the 2 adjacent side times the other adjacent side
That is the cos of the angle we want to find
Sorry my internet was bad
The angle
Use trigonometry
Or calculator
Some angle have easier value
Like cos 45 = √2/2
While cos 50
,calc cos50
The following error occured while calculating:
Error: Undefined symbol cos50
Closed by @lament wraith
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Yeah it's fine
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I am confused about the last step in this example, I understand the solution to be something like x-y=0, but I'm not sure how or why it corresponds to the general vector of the form x2[1, 1].
x-y = 0 is the same as x=y
so any vector of the form (c,c) where x=y=c
(with c nonzero since eigenvectors are required to be nonzero)
ok so x=y=x2, which is why x2[1,1] is the same as x2+x2 = x+y?
yea a general vector with x=y looks like [1,1] times some constant
that makes sense, but I'm used to solutions being equal to something, why isn't it written like x2[1,1] = 0?
well it's not equal to zero, so =0 would not make sense
you could write [x,y] = [c,c] if you want it in that form
where c is any nonzero number
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i struggle to prove the other direction
essentially i need to find some linear map T such that for all linear S, ST = TS
i tried maybe finding some map S that would give me some clues, but i couldn't
you will probably need to pick a basis
no yes
examine the commutativity of $T$ with $S_{ij}$, defined [ S_{ij} e_i = e_j, \quad S_{ij} e_{i'} = 0, i' \ne i ]
actually also yes
but in conjunction with what i wrote above
linear map lemma only ensures S_ij(e_i) = e_j for 0 <= i, j <= n, what about the second clause when S_ij(e_i') = 0?
theres a different S_ij for every pair i, j
there are n^2 different maps you should be considering
for example, $S_{69}$ is defined
[ S_{69} e_6 = e_9, \quad S_{69} e_i = 0, i \ne 6 ]
yeah i understand, but i don't think that answered my question
how does linear map lemma tells us S_69 sends e_i to 0? and the fact that S_69 is unique makes it even less plausible
let us observe the statement
here, the T in the picture is our S_69
V = W for us as well
the basis is e_1, ..., e_n
ive defined
- S_69 e_1 = 0
- S_69 e_2 = 0
... - S_69 e_5 = 0
- S_69 e_6 = e_9
- S_69 e_7 = 0
...
n. S_69 e_n = 0
so here, w_1 = 0, w_2 = 0, ..., w_5 = 0, w_6 = e_9, w_7 = 0, ..., w_n = 0
ahhh, i see
i was under the assumption w1, ..., wn is the list e1, ..., en or its alternate order thereof
that makes sense now
you now should look at how this commutes with T
what does that tell you about T?
in fact, you could even just try proving it for T : R^2 -> R^2
alright, one sec
for arbitrary vectors v or for just the basis vectors?
what does T look like?
er, a map sends elements from a vector space to the same space?
im not sure if you know this answer actually, since its not explicitly mentioned in axler
yes, but theres a way to write it out explicitly in some sense
ill show it, and you can tell me if it makes any sense
,align \MoveEqLeft[6] T(x_1 e_1 + \dots + x_n e_n) \
& = (A_{1, 1} x_1 + \dots + A_{1, n} x_n) e_1 + \dots + (A_{n, 1} x_1 + \dots + A_{n, n} x_n) e_n
epic overfull hbox moment
looks familiar
dont worry i have plenty of hbox
yes because its this exercise that you did
but in a more general setting where we replace F^n and F^m by V
and use bases
oh yes i can see the resemblance now
are you suggesting i examine how S_ijT commutes for e_1, ..., e_n, then extend it using this form?
i think you'll find that you can compute what A_i,j are equal to using the fact that S_i,j and T commute
alright, brb
birb indeed

how would i invoke this in the proof? since i only proved this for L(F^n, F^m)
the proof should be no different really
for example, by the linear map lemma, it suffices to determine what Te_i is for each i
then by the fact that you have a basis, you can write Te_i = A_1,i e_1 + ... + A_n,i e_n
and actually thats the entire proof
you only need this bit
@zinc haven Has your question been resolved?
yeah uh, i'm lost
oh hey we're doing the same chapter

Now use the linear independence of all the e_i
ok so that means A_jj = A_ii

