#help-19
1 messages Β· Page 207 of 1
is that what your original problem says?
Nope it is written in the book just like that
Yupp
hmm hold on.
i am ever so slightly suspicious of this. let me actually run it through my calculator to see if it actually matches up.
actually im dumb nvm
Ok with sin11Β°41'sin18Β°19' it works
Tnx
Its okay people are dummer these days
The very last line
Check that
wait that doesn't even have the minute notation in the 4
then I guess there's a typo
Could be πΆ
May not be as well idk abt these maths π₯Ί
They drive me crazyyy
it would be true if the + was replaced with 1'
Hmmmm.... Ig u have a point
But, it just might not be cuz these writers are weird
They say there is no mistake
aight so
in the interest of clarity i calculated this and wrote out all intermediate results to as many decimals as my calculator would give me
I believe it didn't match the given thing
:O
and yeah shit doesnt add up
i wasnt trying to be neat right now but thank you
π you're welcome madame
Thanks for the help ;')
Am grateful
And am super mad about these rumors that there are no mistakes
Screw those typo creeps π₯Ί wasted so much time
yeah that sort of crap is really infuriating
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help please
have you tried any substitutions like e^x + 1 = u so far?
@elfin vessel Has your question been resolved?
yes i have tired
jelly v20
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How do I find a formula for $\sum^{\infty}_{k=1}\frac{H_k}{k^n}$?
πΈπππππππΒ³
πΈπππππππΒ³
πΈπππππππΒ³
how did you find these values
I must be honest β wolfram alpha
but they do check out numerically
@rancid moat
plz
help meh
$\sum_{k=1}^\infty \frac{1}{k^n}\left(\sum_{i=1}^k \frac{1}{i}\right)$
snowflake
yes yes!
you can rearange like that?
maybe?
idk, how would that π work outside of the lower limits?
i always forget the interchange rules

oh wait yeah that is wrong
isokay β€οΈ
snowflake
but we could rearrange the summations now and get k on the inside
thatβs correct though, Can you merge the fraction into π/πβΏ?
and then evaluate the geo series
no closed form according to this
you can always interchange with positive terms btw
Wait what?
So thereβs no formula, but there is closed forms for some π?
*or π in this instance
$\sum_{i=1}^\infty \sum_{k=i}^\infty \frac{1}{k^n}\frac{1}{i}$
snowflake
more or less closed form for integers m>1
oh that is not geometric what am i doing
ye
so does a formula exist⦠or is this a lost cause⦠
absolute convergence :D
well the post writes a formula which is about as closed formula-ish as I would expect
I cant imagine that such a sum of zeta values has a nicer closed form
Let me find quickly scroll through MSE and see if I should close this channel or notβ¦
because this was only part of a bigger problem of mine
I was trying to find
πΈπππππππΒ³
what is your definition of H_k/s
this really is above the paygrade of a help channel
$H_z=\int_0^1\frac{-1+t^z}{-1+t}dt$
πΈπππππππΒ³
forums?
go into an advanced number theory channel
I just donβt want my problem to get shot downβ¦ 
!close
oop
uh
I forgot
.close?
.close
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guys I messed up both of these apparently.. anyone know where the mistakes happened?
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is the vector (0 , 0 , 2) perpendicular on the zx plane?
What does it mean to be perpendicular on the zx plane
if so why
is that a question to me or you dont understand the question itself
@frank tide is this what youβre asking?
β Orange perpendicular to purple, yes or no? β
ah, let me give the original question
Alright π
"Which of the following vectors is perpendicular on the zx plane?"
1 - vector x
2 - vector y
3- vector z
4- (0 ,0 ,2)
apparently the answer is vector y and i dont really understand why
original question perhaps
Hmmβ¦.do you know the equation that describes the plane xz?
That is not what (0,0,2) would look like is it
Nah, it was a demonstration. All in all, can you takeover?
Sure, I just wanted to confirm if I was tripping lol
I shouldnβt hijack your channel π
I don't have a notebook on me unfortunately
No no I disappeared for a while
I'm at a doctor's
Feel free to take over cuz I'll keep disappearing
normal π ?
you mean like- unit vector version of it
Yes, itβs like the vector that is perpendicular to the plane
And its length is 1
yay
ah yes, just learned the terminology for it
anyways
what do you want the normal vector of
XZ plane
This guy
(1 , 0 , 0)?
alr, so for every ax + by + cz = 0
The normal vector is <a, b, c>
Keep in mind that <a, b, c> is always the vector that is perpendicular to the plane
oh you wanted (x , 0 , z)?
im assuming the <> mean matrices?
im very new to 3d geometry
No, Iβm referring it to vector here.
whats this?
Itβs a plane equation!!
pretty sure i wasn't introduced to that but- ig ax +cz =0 or <a , 0 , c>?
wait fr?
yeah i wasn't
started yesterday
Have you been taught how to find a vector that is perpendicular to a plane in a 3D space?
no, nothing that specific no
i was only taught projection and unit vectors when it came to planes
like how (0 , 0 , 1) is the unit vector for the z axis
a vector is perpendicular to a plane if it perpendicular to 2 or more distinct vector parallel to that plane
yeah i def didnt learn that
Yep, youβll need this information in the following process
Itβs alright, just keep that in mind

Do you need some time to put that in your note?
what are a , b , and c exactly? like in a vector like (2 , 5 ,11)
actually you can look at the corner of your house and imagine that each edge is an axis
Theyβre variables 
OH
yes we do that sometimes
For example
For 3x + 7y - 4z = 0, its normal vector is <3, 7, -4>
oh so thats a plane
and the unit vector thats perpendicular to that plane
is ( a , b , c)
any reason why you type them between < >? is that not a vector
oooh so this is like a function of x and y in the 2d plane
the "plane equation"
it's easier for me to tell vectors from coordinates π
vector has a form (x,y,z) respectively to the axis, so for example u(a,b,c) that mean it go along x axis a unit, along y axis b unit and the same for z
be careful, the length of a unit normal vector is 1, while normal vector can be at any length.
yes!
i understand
everything
proceed please
(super interested tbh)
Right, back to the question
do you know the direction vector of a vector in the direction of x
ik it sounds redundant, but I wanna make sure yk.
what?
i might know what that is but not seem to recognize it bc of hte language barrier, can you clarify what ur talking about?
the direction vector of the first option
any vector that is parallel to the first option
here
any vector with z = 0 and y = 0
Because the vector is in direction of x
oh yes i didnt consider the direction while imagining
yes
I already see the pattern
how about the second and the third option?
yay
alr, have you taken the notes?
Let's move on
ye
a vector that is parallel to for example the z axis has both their y and x = 0
"Which of the following vectors is perpendicular on the zx plane?"
1 - vector x --> (1, 0, 0)
2 - vector y --> (0, 1, 0)
3- vector z --> (0, 0, 1)
4- (0 ,0 ,2) --> (0, 0, 2)
and what does perpendicular on the zx plane mean again?
As we mentioned previously, the plane equation of xz is y = 0, and its normal vector is (0, 1, 0)
and the vector that's perpendicular on the zx plane is the same as the normal vector of the y axis
Absolutely
or... any vector along they axis ig?
does it HAVE to be normal?
is (0,1,0) the only possible vector thats perpendicular on the zx plane
yeah why not?
Normal vector means a vector that is perpendicular
No
so..?
it can be <0, 2, 0> <0, -1/2, 0> <0, 228492, 0> etc
yeah so- it doesnt have to be normal
bc ( 0 , 2 ,0) isnt normal no?
yet its perpendicular to zx
Let's clarify the definition.
normal vector: A vector that is perpendicular to the plane.
unit normal vector: A vector that is perpendicular to the plane and its length is 1
I was unclear when I first mentioned it
ooooooooooh yes yes
unit vector is vector with length 1 or what ever the axis unit is
so an infinite amount of normal vectors and one unit normal vector
wait a minute
nvm
2 actually, it can be in opposite direction
who has a squareroot of one execpt one
<0 1 0> <0 -1 0> both works
oh
yes that makes a lot of sense
tysm sky
for your patience and kindness
have an amazing day
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Iβm deflated
Iβm deflated
Iβm deflated
It is so hard
I cannot get through it without any mistake made
Iβm so sad
Iβm so sad
Traumatized
Thereβs always something wrong
Help me please
Please
I mean to check all of them we have to know mandarin
Or you could provide a translated one
I had checked it
I missed some numbers
π¨π»βπ¦°: it is okay. We all make mistakes
π¨π»βπ¦°:move on. Look at the big picture
π¨π»βπ¦°:you could do it again a week later, but now you should just move on
I will listen to you
I will move on. Thank you
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What have u tried
!msgdel
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uhh i tried to fine tan theta
Can u show ur work
Also u should open a new channel ,this channel is closed
It will be considered available for help soon
oh
do i close this first
2
It's already closed
The channel will timeout soon
it's going to implode in like 3 minutes
oh-
go claim a new one
π i think i did smth wrong
No it's okay,js claim a new channel
i did
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i have a question on how plus and minus work in 'u substitution' when intergrating
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #βhow-to-get-help for instructions).
You can ask the question and give more context like what is it you dont understand etc..
right
lmao
does that plus and minus js stay there?
also how would i intergrate sin^5(x)
ive tried u subbing but im a little stuck
Can u show ur work
Try converting the sinβ΄u into cosine
And then u can do a sub for cos
Yes using that
Np
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Need help.
This is my 11 years old younger sister's math problem, but we've both forgotten how to solve it.
Calculate B = 2^2 + 2^4 + .... + 2^2024 + 2^2026
I know it's supposed to be some sort of sum, but I don't know how to change it to one.
Thank you if anyone decides to help
That is the sum of a geometric series
looks like it
So your sister should have been taught the formula for it
Sn=r(1-r^n)/1-r
She, apparently, forgot (which is why I'm here)
think this only applies if |r| < 1
which it is
in our case
its supposed to be multiplied by a
not r
that was my mistake
$$S_n = a_1 \frac{1 - r^n}{1 - r}$$
are we saying that |r| < 1 here?
because i don't think so...?
this is the question
What's S, a and r? Sorry I'm really bad at notations (is it what they're called in English?)
Alberto Z.
r is common ratio
S is sum
No no you're right
|r| < 1 is needed if the sum goes on till β values
If she forgot it, isn't she able to find it in the textbook or in the lecture notes?
My sister still doesn't really understand anything,, I'll try plugging the equation/wherever whatever into the formula to figure it out
Most likely left that at class, I think
i mean fair enough
we are 15 years old here in my country
and we have just learnt
AP
I'm also 15... whoops.
oh
(Math was never my strong suit basically)
well this is a tad bit awkward innit
same but lets not go offtopic
Indeed.
Where are you stuck?
uhh he just forgot the sum of first n terms for gp , all g now
Dont wanna be rude. But you can just google such stuff
a1 is the first term (in your case |2Β²|) and r is the common ratio (in your case |2Β²|
n is the number of terms you're summing (which you have to figure out here)
@vestal beacon
What's a?
Ah
Thank you
i guess your first step is to find n
I guess there are... 2026 of them? considering,, it ends at 2^2026
Sorry English isn't my first language
If you all want, I can close this channel (My sister gave up)
She's also saying her teacher gave her a different method asw
not exactly
see that the power goes up by 2 each time, not 1
and also, don't worry about the language! just let us know if you don't get a certain part
Oh so that's what it meant,, the total of numbers inbetween
yep! the total number of numbers in the sequence (or more properly, the total number of terms)
My calculator is... refusing.
what did you type in your calculator?
It's been so long since I last touched something bigger than 2^2 I'm so sorry
I was testing,, I wanted to see if it could handle a massive number
technically speaking, all you need to do is look at the power (the smaller number to the top right)
notice that it starts at 2, and for every subsequent number it increases by 2
and it ends at 2026
Yes,,
so if i ask you how many numbers are in the sequence (2, 4, 6, 8, ... , 2026), what would you tell me?
If nobody minds, I'll close this channel
I think I'm freaking out worse than ever
So sorry everyone
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thank you
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very confused on this
wha
!status
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
What have you done so far
i looked at trig identities and im not sure entirely where to modify it to work
cus i know theta is basically x if i can get the right form
i think
Well what is csc x
1/sinx
Good
which could then be x/cos9x sin4x
And what is the limit of cos 9x as x goes to 0
so then x /sin4x
still a little lost, do i just reverse the denom and numerator somehow
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Im doing set theory, its only week two of classes and im stressed the fuck out, havent taken a math class in 5 years pls help
ok so the universal set is A-Z and i just have no clue how to solve this, i dont understand why the fuck the parentheses are here, the comma is the complement but i dont get it
you can just ask your question here
and heres my other thing, if i get help with these two im sure ill be able to finish the rest of the assignment
if you're struggling with notation, this is pretty simple https://www.storyofmathematics.com/set-notation/
The parenthesis are there to indicate that you are taking the complement of the entire set A n B. Because A n B' might be interpreted as the intersection of A with the complement of B'
Read the question after the one with parenthesis
BnA'?
.
The parenthesis tells you what to do first. The parenthesis around A n B in (A n B)' means you do A n B first, then take the complement
While A n B' means you take B', then intersect with A
I repeat: these two will give you different results
the complement is everything in u that isnt in any sets right
The complement of a set is everything in U that is not in the set
So the complement of B would be all the letters except {r,e,d}
This is not helpful. They don't understand the need for parenthesis which is not covered in this article.
everything not in a
What is B n A' then?
Everything that is in B and not in A
Can you explicitly write the set A' for me?
@dense phoenix
{D,E,F,G,H,I,J,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z}
no single article is going to explain every single thing
feel free to add to the article instead of complaining
That's not how intersection works
I just added it- an explanation
You may want to read riemanns article or just this:
The intersection of two sets are the common elements among them
my brain just isnt built for this
What's common among {R,E,D} and {D,E,F,G,H,I,J,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z}
r e d
what i dont understand is why is e and d still in it
i just dont understand
bc thats not in set a
Yeah
So they're in A'
Then you are looking at what's common in between A' and B
You are doing B n A'
Not B n A
B n A' is what is common in between B and A'
A' is stuff that's not in A
So B n A' is stuff that's common in between B and (stuff that's not in A)
Being frustrated will not help. If you think my explanation is not helpful you can read the articles or wait for someone else
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idk how to sketch vectors please help
like where did theta spawn from
it says heading due east why is theta not just automatically 0
yeah but drawing for some reason I can't do
Well, in the most basic sense, vectors are essentially arrows pointing to some place with a certain direction
you have two ways to express that fact:
- You find the X,Y coordinates the end of the vector points to.
- You find how long the vector is, and in what angle is pointing to. Which is usually known as 2d polar coordinates R,ΞΈ
Youll 99% of the times be using the first one
okay, so how would I go about this problem?
yeah
Sadly, when doing this sort of problems, you are usually given the second form of the two vectors
R,ΞΈ,
R = the force/speed, ΞΈ = the angle in which that is applied
There is a way to convert it to x,y anyways
for a pair R,ΞΈ, the "equivalent" X,Y pair is
X = R (cos ΞΈ)
Y = R (sin ΞΈ)
okay yeah that I remember
but I'm still confused on the drawing
how do I know I needa use the 45 degrees
The drawing is poorly done anyways btw
like, the math is good, but the drawing is completely skewed
bruhhh
For drawing vectors, you just chain them together
Specifically, the end of the previous must be the start of the current
Which you can prob see is not done in the drawing
The blue vector should be below the "east" line
ahhh I see
Well, thats basically how to graphically sum vectors
the end of the blue point connected to the (0,0) is the new vector
yeah that makes more sense
yeah
eventually the book computes theta to be ~9 degrees
so ig the red is not directly on the east line
If you give me a sec ill fact check that
okay bet
about ~13 deg, they got lost with the drawing
maybe i got the problem wrong and is not just summing speeds, but i think the text could be wrong
Yeah, i tried doing doing as they did and i get 9.03 deg, the "correct" way (the one i stated) leads to 13
oh, my bad
its not absolute speed
Its relative to the water itself,
then its ok, since, if the water is moving past us, we are moving past it from that perspective, you use the opposite vector
I see
yeah I think I'm just gonna spam some problems and look at other books
it really doesn't seem like a difficult concept
I'm just selling the bag
The vector sum should look like this if we stick to how vectors are added geometrically, but the result will be the same
The problem is kinda strange by asking relative to the water, but it makes sense ig.
okay cool, noted
yeah, the ~9 deg is correct then, mb, thought it was relative to the shore
okay cool perfect
yeah I understand it a bit better now I'll just keep practicing
tysm for the help
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how can u prove cos(2x) = 2cos^2(x) - 1 without using pythagoream identity?
So without $\sin^2 x + \cos^2 x = 1$?
casework
yea
Idk why would you wanna do that
Like surely whatever you use will just be equivalent to that identity
I mean here is 1 take ig
You can take the derivative of $\cos^2 x $
That is -sin(2x)
Now integrate that. That is cos(2x)/2 + C
And fix up the constant to its 1/2
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Hello
I need some assistance, with the point slope equation
This so far is the problem. And what Iβve done on it
that handwriting tho lol
Sorry my hands keep shaking I feel really uncomfortable right now but Still trying to push thru my work
ok lets see, first step is good 4x+7y =9 you do y from here
y= (-4/7) x + (9/7)
the slope : -4/7
Wait so I got it wrong?
it's from 4x+7y=9 you do y from here: 7y=-4x+9
y= -4/7 x + 9/7
you can see here m = -4/7
So just the x and y ??
Thank u
This is the next part right?
yes
you need to do it for (4, -2)
there is next part after that for perpendicular line through (4, -2)
it's reverse/negative reciprocal of -4/7
that's 7/4
se we're here now:
y -(-2) = -(4/7) *(x-4) for parallel line
Yes
ok so we do y from here:
y = -(4/7)x + (16/7) -2 just shift the 2
Subtract 2?
y+2 you need to put it on the right side
From both side?
no
And add 2 to the right ?
then you * the 2 with 7/7 so it becomes 14/7
basically same
you're multiplying it with 1 but that one becomes 7/7
and the whole becomes 14/7 which is 2
so that you can do 16/7 - 14/7
I donβt have a 14/7
so parallel line: y= -4/7 x + 2/7
that's that
are you confused about some part of this?
Yes
ok which part?
Yea
Im just not good at this types of things
14/7 is practically 2 mate
so we have 16/7 and a 2
we need to make that 2 -> x/7 so that we can calculate those numbers
so we do 2*(7/7) (7/7 is practically 1)
2*7/7 = 14/7
14/7 = 2
so you don't change anything of value
just the equation
if you divide this 14/7 you get 2 so think of it as 2 transforms into 14/7
because of the 16/7
Yeah
I get how to get the 2/7 u simplify
To get the 14/7 out of 16/7 tho I donβt
Now how do u do perpendicular lines?
it's really simple mate so i'll go through it again ok?
Nah Iβm fine Iβmtired of math
first you find slope:
4x+7y=9
you do y from here, transfer 4x on the other side:
7y=-4x+9 (when you transfer it becomes - if it was +)
so from here you find y, transfer 7 on the other side:
y=-4/7x +9/7
if 7 was * on the one side it becomes /7 on the other
and the slope is -4/7
so we have (4 , -2) as point
y-(-2) = -4/7(x-4)
in other words y-(second number) = -4/7(x-firstnumber)
Itβs alright I donβt want any,ore help Iβll just accept it
-*- = + so
y+2 = -(4/7)x+16/7 -> 16/7 is because -4/7(x-4) -> we multiply -4/7 with x and with 4
transfering the 2 on the other side:
y=-4/7x + 16/7 - 2
we multiply the 2 with 7/7 because of 16/7:
y=-4/7x + 16/7 - 14/7
y=-4/7 + 2/7
that's for parallel
perpendicular you need perpendicular slope
so you do negative reciprocal of the slope:
-4/7 -> 7/4
and do the equation:
y-(-2) = 7/4(x-4)
y+2 = 7/4x - 28/4
Ohh thatβs what I messed up
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not sure whats wrong
do they somehow want "odd number" to refer only to positive odd numbers implicitly
guys it looks like i just left it blank i swear i had 2n-1 in before
errr
is this the entire question or part of a bigger one
yeah let's take a look at the whole thing
dunno why the other parts would matter as much tho
2n+k should give 9 at n=1, that's how you get your k
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@silk fox
Hi - sorry about that
It does add up to 6
I also don't know how to prove it
I know chatgpt is discouraged but I use it for these cases
damn
So may I ask what's your question here?
well
i've decided to skip it
we were trying to solve the series n^2/2^n
Other then like this?
well i got to $\sum_{n=1}^{\infty}\frac{n^2}{2^n} = 2 + 2\sum_{n=1}^{\infty}\frac{n}{2^n}$
creeperdoesredstone
I am also getting somewhere like that.
Using n = n+1
If you write the sum of n/2^n in a triangular array
You get 1 + 1/2 + 1/4 + ... for each geometric sun
*sum
@proper maple Has your question been resolved?
You sure it is 2+?
Maybe I am also doing something wrong.
Oh wait right it is +2
Here is a whole solution.
Do you even know what did I do?
no not previously of course i'm looking at it trying to understand but i get the gist of it
you "pushed back" the series
then expanded
split the sums
Yes but also realize that we used the fact that the sum is 0 at n=0. Otherwise you also need to add it.
I mean subtract.
I would suggest you to try it on other examples as well to see the details or do this without looking.
thank you.
i'll save this for future reference when these situations come up again
thanks!
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@serene torrent
i've just realized something
i'm so stupid
the exercise asks whether the series converges or not
nothing about finding its sum
π€¦ββοΈ
regardless this proves really useful as i'm sure i will need it in the future
it's good to know
It is only useful if the series converges tho.
true
I am a bit rusty with my series convergence tests but a ratio test should solve this.
yeah no it's relatively easy
ratio should solve
also no need to prove an >= 0
well i mean
i do need to prove that still
to be rigorous
but you get me
see this is what confuses me
how do i say n^2 >= 0 for example
can i say oh well its a natural number starting in 1 which then only grows
and on top of that its squared
of course all that in math lingo
Foe reals n^2 is positive.
I would say abs(...) = ... maybe.
im not debating that
same for 2^n
like i know for a fraction if both terms are always positive then the fraction is always positive
same for if they're both always negative
I am not good with proofs so someone else can help you better. Sorry.
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in this triangle (ABC) of lengths sqrt(2) , sqrt(2) , sqrt(6), theta=?
ik you can get (180 - theta) by one of the trig identities that includes cosine(180-theta) but! when i first attempted to solve this question, I didnt use trig and I used anotehr approach and i got a terrible answer, i just wanna know what i did wrong.
area of ABC = 1/2 x length x length x sine of whats between them. lets call whats between them here "180-theta" or just "theta" considering that e sin(180-theta)=sin(theta)
OK- so 1/2 * sqrt(2) * sqrt(2) * sin(theta) = area.
so sin(theta)= area.
theres a formula relating the lengths of a triangle to its area (its called her##ne formula? idk his name sounds weird in arabic)
anyways... area of this whole triangle is sqrt(3)/2
sin(theta)=sqrt(3)/2
theta = 60
car
ignore the guy on the left
Donβtβ¦leave him alone
,calc sin(2pi/3)
Result:
0.86602540378444
,calc sin(pi/3)
Result:
0.86602540378444
,calc sqrt(3)/2
Result:
0.86602540378444
aha?
,calc sqrt(2)*sin(pi/2 - 2pi/6) * sqrt(6)*1/2
Result:
0.86602540378444
am i supposed to be catching something
,calc sqrt(2)*sin(pi/2 - pi/6) * sqrt(6)*1/2
Result:
1.5
Yes
care to elaborate further? i dont quite understnad
Is 60 degree the only valid input of sin whose output is sqrt(3)/2
no
180-
OH
.
oooh π
ok so
after confirming that 60 iswrong
i shouldve checked for the other equivalent angle
ok- failed at 6th grade math
nice
ok ty
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The heat of combustion of ethane gas is 373 kcal per mole. Assuming that 60% of the heat is useful, how many litres of ethane measured at S.T.P. must be burnt to convert 50 kg of water at 10Β°C to steam at 100Β°C ? One mole of a gas occupies 22.4 litre at S.T.P.
Please don't occupy multiple help channels.
Q1β=mcΞT=(5.0Γ104)(1)(90)=4.5Γ106Β cal=4500Β kcal
whatβs going on there
not given
Yeah you donβt need
Q2β=mL=(5.0Γ104)(540)=2.7Γ107Β cal=27000Β kcal
Wait does this require latent heat asw
Iβm asking on the basis of the question
is this for water
540 from where
yes man its for water
no im asking how did you get 540
That 540 cal/g is the latent heat of vaporization of water at 100 Β°C (at 1 atm)
oh
now bye bro i am playing Lord of the fallen
divide by 60%
since 60% of the heat from ethane combustion is useful
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hey, i need to prove that q has a global min and its <0
so ive shown that it has a global min
but <0 is harder
$q(0) = -2$
Ann
ik
whatever the global min is, it cannot be greater than q(0).
but how to prove thats the global min
Bruv
you don't prove that the global min is achieved at 0
it could be achieved at x=0.42069666867530911111131415 instead
You agree that the minimum is less than or equal to -2 right
Cuz itβs minimum
but whatever your global minimum is, it cannot be greater than any value of q at any particular point.
agreed to this
and this
Then qed
but a,b,c are just parameters and we dont know if its <0 or >0
oh i get u now
thx
q(0) lowest
as the def of a global min
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β
right im sry what im sayin is that if s is the min then q(s)<=q(0)
we know that min q β€ q(0), yes.
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My answer is in the red circle
!status
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
show original problem too
it seems that the 96 in this snippet is also sus -- shouldn't it be 96t instead?
this part is correct btw. you applied the product rule correctly. but you fumbled the algebruh that follows it.
oh damn bruh let me redo it rq
dont be quick about it
carefully I mean
time to go papers please on your thing to sniff out even the slightest error
so this expansion is legit
but then your like-term collection got fumbled
in particular the t^3 terms
-64 - 3 - 1 - 64 = -128 - 4 = -132 and not the claimed -120
and then also
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hmmm hold on. there's some big question marks in there.
- is X withdrawing the whole lot at the end of '10, or only part of it? (or even, when is he withdrawing?)
- does X also have to pay 30% tax on whatever he withdraws? or, maybe more sensibly, on just his interest?
- is this interest simple or compound? (i'm guessing compound, but explicit confirmation would be nice)
do you by any chance have the original problem exactly as written
cause i really really think there's some weaselry here
like
X and Y are both withdrawing at the end of '10 right
it's not explicit in here
so wait. X pays tax on the principal as well? is that what you're saying?
the second that X's β¬8440 lands in his deposit account, X knows he's already on the hook for 30% of that to the tax man even before he gains any interest?
that sounds monumentally stupid.
so 30% tax applies only to the interest.
yes
and we want the net payout (post-tax) to be the same.
yes
