#help-23
1 messages · Page 186 of 1
i don't
i thought it had something to do with limits from both sides
and epsilon delta is the tool for it
@white umbra considering his current foundations I think we should work out my example g first
the function with the one higher point?
You can step in if you want
Oh alright
Yeah let's talk about that example function g
So let's say g(x) = 1 when x=0 and 0 when x≠0.
Where is it continuous?
Yup
So intuitively that's because if you move a bit, the y-value doesn't change a lot, right
but in the case of x = 0, when we apprach it from both directions, we actually got to 0 instead of 1
Yeah exactly
When approaching from both directions, we get the same value
But it also has to match the actual value for the function to be continuous
the limit from sides has to be equal to the image of that value
ok got it
and how does show it mathematically?
like lim x - > 0 (g(x)) = 0 = / = 1
?
Yeah you would write it like
[\lim_{x\to 0}g(x) = g(0)]
if (g) is continuous at (0)
pERICyclic_reaction
But in this case, the left-hand side is 0 and the right-hand side is 1
So it wouldn't be continuous at x=0
Does that make sense?
Okay cool
But then there's the question: what does a "limit" actually mean, rigorously?
It basically means I can get as close as I want, right?
something with sequences
yes
So to write that in rigorous mathematical notation
I like to think of it as a game
If [\lim_{x\to0} g(x) = 0]
pERICyclic_reaction
Then that means I can get g as close as I want to 0, so if I tell you I want to make g(x) really close to 0, like between -0.1 and 0.1 for example
Then you should be able to tell me how close I need to make x to 0 to make that happen
So like for example "if 0<|x|<1, then |g(x)|<0.1"
Does that make sense?
yeah?
so
i keep plugin in x values from the domain that make g(x) get closer to the 0
are we still talking about the same g function?
yeah ok
So you could really tell me any value of "closeness" for x
Like for example you could equally say
"if 0 < |x| < 10000, then |g(x)| < 0.1"
and that would still be valid
But in general, if g wasn't constant, then you might have to make that closeness value for x really small
In order to get g(x) into the desired range
Does that make sense?
But in general, if g wasn't constant, then you might have to make that closeness value for x really small
why?
Let's think about another example, g(x) = x^2
ok
Let's say I tell you, I want |g(x)| < 0.1
And I want to know what x values are acceptable
If you then told me "0 < |x| < 10000"
That wouldn't work, right?
but it would no?
How come?
like x = 100000 lets say
Yeah
that squared is smaller than 0.1
xD
Yeah so you have to make the bound on x pretty small right
like for example you could make it
yes
yup
And then if I told you like
I want precision to within 10^-6, so |g(x)| < 10^-6
What's some bound on the x-value that you could choose to guarantee that?
0<|x|<10^-4
yup
So now the point is
No matter what precision value I pick, whether it's |g(x)| < 0.1 or |g(x)| < 10^-6 or whatever
You can find an appropriate range of x which guarantees the precision I want
That's the definition of a limit
ookkk
So we define
[\lim_{x\to a}f(x) = L]
to mean that for any (\epsilon>0) (the precision I want), there's some (\delta>0) (the range on (x) that you pick for me) so that (0<|x-a|<\delta) guarantees that (|f(x)-L|<\epsilon).
pERICyclic_reaction
Or to make it more concise,
[\forall\epsilon>0,,\exists\delta>0,,(0<|x-a|<\delta)\implies(|f(x)-L|<\epsilon).]
pERICyclic_reaction
|x-a| is the distance between x and a
in the previous example, I had x→0
so it was the distance between x and 0, or |x-0|, or just |x|
but in general, I can have x approaching any value a
and then I would want the distance between x and a, |x-a|, to get really small
does that make sense?
yes
awesome
So now your challenge is, consider again that function g which was like g(x) = 1 when x=0 and 0 when x≠0, prove to me using this definition that g is not continuous at x=0.
ok
when trying to apply the definition of limit to a function
do i use actual values for my epsilon and delta?
So when you want to prove a limit holds, you need to show that it works for any possible value of epsilon
So you won't use actual values
But when you want to prove a limit doesn't hold, you just need to find one value of epsilon that it doesn't work for, and then you need to show that no value of delta works
So that's a case where you'd want to pick an actual value for epsilon and then show that no possible value of delta works
Yup
and
i guess I can't use 1 which is the limit itself to check
sorry I mean 0
I have to check the function at all values except for the value of the limit that I'm testing
Right now I just want you to show that
[\lim_{x\to0}g(x) = g(0)]
is false
pERICyclic_reaction
yeah, the limit doesn't depend on g(0)
right
and you want to prove that there's no value of delta so that 0<|x|<delta guarantees that g(x) is within 0.1 of 1
So for any value of delta, there's at least one value of x where 0<|x|<delta so that g(x) is farther than 0.1 from 1
and
i just take a look at the function
I see that for no value of x regardless of delta can the function every be closer than 1 to the limit
Yeah. That's right.
So that proves the function isn't continuous at 0.
Let's now try this with the original function
ok
I would first
set an epsilon value as an irrational number
a really small one
and then
do
| f(x) | < ε
wait nvm
I select a really small irrational delta
wait im confused
say ε = 0.1
and we wanna show that no value for x fulfills | f(x) | < 0.1
there will always be a value that fulfills this tho
ok
And we want to show that for any delta, there's some x satisfying 0 < |x| < delta so that |f(x)| ≥ 0.1
ok
how would we go about that?
is it possible to say that delta is an infinitely small irrational number?
No, there's no such thing as infinitely small.
wait
And then you have to choose a value of x according to the delta that I gave you.
Yes, showing that there isn't a delta value that works is equivalent to showing that all delta values don't work.
:D
So for every delta value I give you, you need to demonstrate that you can show me a value of x that's a counterexample
i.e. some x where 0 < |x| < delta but |f(x)| ≥ 0.1
Does that make sense?
yes
and regardless of the delta, we can always subtract a really small irrational number from delta
and land on an x value, where when we take it and plug it in f(x), we are not in our epsilon value range
That's the right type of reasoning. You need to be a little more careful though because if my delta is irrational and you subtract an irrational from it, the result might end up being rational.
But it's true that there's always some irrational number x between 0 and delta.
And then how do you know that f(x) is not in the range, i.e. |f(x)| ≥ 0.1?
because it is more than at least 1 away from f(0)
why?
Well let's do an example right
Let's say I pick the delta value 0.1
and you pick an irrational number between 0 and 0.1
ok
And you know that's more than 0.1
It's not more than 1 though, like you said
Let's say I give you a value for delta
Can you pick x to be any irrational number between 0 and delta?
Or is there some sort of restriction?
yes why not
Well let's say for example I pick delta = 1
ok
And you say let x be any irrational number between 0 and 1
ok
So I say okay pick an irrational number which is really really close to 0.99
Then what's f(x)?
really close to 0
yeah, really really close to 0.01, and that's less than 0.1
but your claim was that it was more than 0.1
So we need to do some sort of fix to make sure x can't be chosen like that
Does that make sense?
Yeah
u wrote |f(x) - a| < ε
but here you wrote the opposite
Yeah that's because we're trying to prove the opposite
We're trying to show that the limit doesn't exist
ok ok
Or at least, that the limit is not equal to f(0)
So this is saying that the limit is L
To say that the limit is not L, we would have to write this
[\exists\epsilon>0,,\forall\delta>0,,\exists x,,(0<|x-a|<\delta)\text{ and }(|f(x)-L|\ge\epsilon).]
Make sure you understand where that comes from
pERICyclic_reaction
(Btw I actually forgot the "forall x" in the original, so lemme retype the definition of the limit being equal to L)
[\lim_{x\to a}f(x) = L]
means that
[\forall\epsilon>0,,\exists\delta>0,,\forall x,,(0<|x-a|<\delta)\implies(|f(x)-L|<\epsilon).]
pERICyclic_reaction
ok
in order to prove that a limit doesn't exist
can we change the for all x to there doesn't exist an x
and keep everything else the same
So when you negate something
You flip all the quantifiers
So "for all" becomes "there exists"
That's because to disprove that something is true for all x, you only need to find one counterexample, so there exists an x so that it's false
Similarly "there exists" becomes "for all"
Hopefully that makes sense
yes it does
I have to go now, but I hope this was helpful. These steps here are also very well thought out ^
But to solve the problem we were facing, try considering an irrational x which is between 0 and delta, and also less than some value that will make sure I can't do something sneaky like pick x to be an irrational value close to 0.99.
No problem!
And then once you've figured out how to prove the function is discontinuous at 0, try proving it's discontinuous at other points too. What you really want to prove is that it's discontinuous at every point except for 0.5.
And then finally, prove it's continuous at x=0.5.
Good luck.
@mild bridge Has your question been resolved?
@mild bridge Has your question been resolved?
@mild bridge Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
Am I doing this right?
And what happens to the y(x) that's being integrated? Would it become Y(x)..?
if I want to do partial decomposition(?) how would that look with the y(x)? or is it "illegal"?
for simplicity, let y(x)=y, this requires something called an integrating factor to be solved
MY DIFFERENTIAL EQUATIONS PLAYLIST: ►https://www.youtube.com/playlist?list=PLHXZ9OQGMqxde-SlgmWlCmNHroIWtujBw
Open Source (i.e free) ODE Textbook: ►http://web.uvic.ca/~tbazett/diffyqs
In this video we do a full example using the method of integrating factors to solve a first order differential equation. The first thing to observe is that this i...
i dont exactly remember the steps though but it's uhh
this may help
With that said - is the approach I was going for impossible?
and what the frick would the integral of 2x/1+x^2 be?
ln(1+x^2)
man do i feel dumb
i was thinking i had to do something with arctan
because the derivative of arctan is 1/1+x^2 right?
yes
so to dumb it down for me
if the nominator is the derivative of the denominator
you just do ln(denominator)
yes
i have nothing but the utmost love for u <33
then $\int \frac{f'(x)dx}{f(x)}$ is $ln|f(x)| +C$
Why am. I here
Closed by @storm ice
Use .reopen if this was a mistake.
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.
i have no idea how to even start this question:(
,rccw
so you know m = 3/2 for both right? @tender hill
mhm!
if the lines are tangent to the circle, so the perpendicular line from those lines (at the point of tangency) would be the radius
lets call the point of tangency for the first line to be $(a,b)$, then the equation of the circle would be [
y = \f32 x + b
]
and the radius from the point $(3,-3)$ (the origin) to the point of tangency can be given by [
d = \f{\abs{ax + by +c}}{\s{a^2 + b^2}}
]
i think what what you can do here is recognise that you have [
y - \f32 x - b = 0
]
and then substitute to get [
\f{\abs{-\f32(3) + 1(-3) - b}}{\s{(\ff32)^2 + b^2}}
]
is this fine? @tender hill
ive never seen this before :(
its the equation of like the distance from a point to a line
was it not covered in ur syllabus
it wasnt
that sucks i think you get a quadratic to solve and then using that equation u can recover the point
and that should be it
ah a;rghty then
i might have fucked up though because i dont think there are any real solutions for b
let me scan
[
\s{52} = \t{Radius} = \f{\abs{-\f32(3) + 1(-3) - b}}{\s{(\ff32)^2 + 1^2}}
]
okay ig that should be fine
anyways @tender hill
we can use this to verify our answer
but what have u learnt so far?
maybe i can gauge a different method
@tender hill Has your question been resolved?
Closed by @tender hill
Use .reopen if this was a mistake.
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.
Ummm helo?
There is no question.
try some easier problem before attempting harder ones mate
Yes i had done it
Now about the b guy
Multiplies are easy
But when they meet add
They say "im gonna end this man whole career"
@royal sorrel Has your question been resolved?
@royal sorrel Has your question been resolved?
<@&286206848099549185> please Q_Q
Ive tried, and the answer i made doesnt make sense
You don't need to multiply them, there is a general rule to dividing numbers that have the same base but different powers
b^(-3x+3y)?
You take the numerators power and subtract the denominators power. Also I would keep the x and y on separate powers @royal sorrel
No
oh wait i didnt see it properly
a^(3x - 2x) * a^(-y - 3y)
b^(-2x-x+2y) + b^(3y-x+2y)
b^(-3x+2y) + b^(5y-x)
I would keep for simplicty the x and y seperate or you can do power rules
a^(3x - y)/a^(2x + 3y) and then
a^(3x - y - 2x - 3y) then combine like terms
but this question act as preface for the log...
i must answer the b guy first
i tried, and the answer didnt make any sense
similar to how l hopital rule doesnt make any sense when studying limits and after learning derivatives we only use that
Ah there is more above
You can split that into two separate parts
$\frac{b^{-2x}}{b^{x} * b^{-2y}} + \frac{b^{3y}}{b^{x} * b^{-2y}}$
dragonbreath
so the answer ends with +?
My connection was so spotty for and so weird, it sent my messages but didn't recieve all of the messages just bits of the conversation so sorry for the untimely interjections
If you want it too
In order to add they would have to have the same power and you would add the bases
Nvm, was thinking of sig figs I think
For the most part yes
You can try and combine the fractions but you'll need equal denominators
hmmmm
It'll probably be an uglier equation
if it ends with + , then it cannot be really called simplified...
I don't think there is really a fun way to get rid of the +, if there is I am unaware of it.
Closed by @royal sorrel
Use .reopen if this was a mistake.
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.
Is this graph answer [0,inf)U (3,3] U (2,inf)?
"answer"?
What about that graph are you saying fits those ranges combined?
Interval notation
Oh, the range?
this doesn't tell us much
Oh my bad I meant the range
Yeah
It looks like it's the ranges of each piece of the piecewise function.
So is this the correct range answer?
(3, 3]?
Yeah, just fix the (3, 3]. (3 means it's higher than 3.
you are technically right but unsimplified!
[0, +infty) already includes both {3} and (2, +infty) as subsets. so no need to state them twice.
You'd write [3, 3] or {3}.
But the first point isn’t included
Yes, but it's not about the first point. Like your quadratic there doesn't start with 0, but it reaches it.
So, you'd have [0 because 0 is in it.
Same with the [3, 3].
It's about the collection of outputs, which goes as low as exactly 3.
So, exactly 3 is [3.
It's [lowest, highest] or (lowest, highest] or whatever.
The lowest is exactly 3.
So, [3.
It's not [leftmost, rightmost].
So I just change the (3,3] to [3,3] and my answer is right?
Yes, but it's not simplified.
Like with [0, infinity), [3, 3] is inside that.
So, you can just do [0, infinity) by itself because it handles [3, 3] for you.
Same with [2, infinity).
Those numbers are already in [0, infinity).
So, you can just say [0, infinity) as the final answer, because it contains every single output.
And it doesn't include anything that's not an output.
So, it's exactly the numbers that you can get as outputs.
Nothing added in, nothing removed.
Does that make sense?
The only reason you'd use U in the final answer is if there's gaps between two intervals.
Ok so a graph like this is [0,5]U(2,5]? For the range
Yes, and then there's no gap between the intervals.
Like you don't stop at 5 for one and then start at 6 for another.
Where there's a gap.
Yeah so [0,5]U(2,5] would be correct for this graph right
It wouldn't be simplified. I'm drawing something related.
So the answer is just [0,5]??
See how they overlap?
Like both of them handle 2 to 5, right?
They overlap there.
Ok so it’s just [0,5]?
Yes, but there's a trick.
You have two lower endpoints.
Like (a, b] and [c, d) have (a and [c as the lower endpoints.
Is this interval notation still a right answer?
No, you want to simplify it.
It's correct, but it's not what you should submit.
So, what you do when they overlap is that you see which starting endpoint is lower.
Like if it's (3, 10] and [4, 25), you have (3 and [4. (3 is lower.
So, you write (3 in your final answer.
On the ending endpoint, you look at which is higher.
- is higher than 10].
Damn that’s what I submitted my answer as
Kinda
But I should still get full points?
It's possible, but you might get a point or two taken for not simplifying it.
Knowing how to combine overlapping intervals into one is a good thing to know for these problems.
Like you have [0, infinity) and [3, 3]. The overlap. The lower starting number is [0. The higher ending number is infinity), so [0, infinity) is their combined interval.
Ok so this would be [0,inf)?
Then, you have (2, inf). It overlaps [0, inf).
Yes, that's right.
The intervals overlap.
Right, you graph them and see if they overlap.
Then, if so, you take the lowest start and the highest end for the combined interval.
And [3 counts as lower than (3. 5] counts as higher than 5).
That's because 3 is lower than the numbers just above 3, and 5 is higher than the numbers just before 5.
Which problem u talking about
Oh, the example.
The question is, if you have [3 and (3, which one wins?
The square bracket one wins.
Same with 5] and 5). The square bracket wins.
If the numbers are the same, but you have both square and round brackets, pick the square bracket.
It wasn't about a problem you posted.
Just rules for how to combine them.
Why
Can u show an example
( means it gets close to 3 but never reaches it?
Right.
Anything just above 3 is fine.
But 3 isn't.
So, [3 can go a little bit lower because it can actually become 3.
So, if you're combining two overlapping intervals, and the number on the left is the same for both intervals, you want to pick the one with a square bracket if one of the intervals has one.
If it's (3 and (3, you just do (3.
If 3 isn’t fine then why would u include the [
3 is fine when you do [3.
I was responding to this ^
(3 means anything just above 3 is fine.
(3 means 3 isn't fine.
But [3 means both 3 and anything just above 3 are fine, so it can get a little bit lower.
Does that make sense?
Well, I've said a lot of things. Which one are you asking the meaning of?
That u always use [ over ( if they’re same spot
Oh, I see.
Yes, that's right.
They overlap, which is very important, since you need that to combine them.
Then, you have [0 and (0. The numbers are the same, so you pick the [0 if it's there.
Like if it was (0 and (0, you just have (0.
But if it's mixed like that, you do [0.
👍
@stiff vine Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
how to find the center of gravity?
@narrow vault Has your question been resolved?
@narrow vault Has your question been resolved?
#old-network for physics server
Or go hire a physics tutor
im definetly not hiring anyone
hiring a tutor is for people who are too lazy to study
.close
Closed by @narrow vault
Use .reopen if this was a mistake.
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.
I'll probably need more help soon, but this is my biggest source of confusion. The whole page has me nervous, and I just cannot work out practice 2. I've tried -40 + 360 and -40 - 360, but it's never between the given numbers T~T
well subtracting 360 isn't going to help, because that'll make it more negative
you added 360 once and didn't get there
how about doing it a second time?
I know, I just didn't know what to do D:
ooo
I forgot you could do that, omg xD
you're amazing
680 would work, right?
yep that's correct
it's basically the same idea
take the first number on the left, 30 degrees
match it with a number on the right that is coterminal with it
meaning, a number that differs from 30 by a multiple of 360
like just the -360/+360 stuff again or would stuff like 12 be involved since it's a multiple of 360
if that makes sense
nope, just -360/+360 stuff
oki cool cool
"coterminal" means they agree to within a multiple of 360
yea, it shouldn't be too bad, and it gets easier as you go along because there are fewer options to check
yeh :D
I can definitely do this on my own time, are you cool to help me with 4 b? I can do a, I hope xD
sure, do you know in general how to convert from radians to degrees?
I took notes today, lemme grab that rq
probs should've done that beforehand, sorry abt that
nw
180/pi is involved for sure!
well that's good :D
it's:
angle in degrees = (180/pi) x angle in radians
oooo right
I'll rewrite that down xD
this is probably very wrong, but would that result in (1260pi)/(9pi)?
yes
:D
but that can be simplified quite a bit
ofc ofc
oh, i see they want decimal digits anyway
so you'll get to break out the calculator or software
(actually it turns out you don't need a calculator, the numbers are nice)
(I'm not that smart, sob)
since 9 divides evenly into 180
well if you left it as 180 x 7 in the numerator instead of multiplying it out
then the 9 in the denominator
divides evenly into the 180
but if you didn't notice that, no big deal, just plug it into your calculator
I'll just plug it in so I don't hafta deal with pi as much xD
o h
so you can immediately simplify it to just 1260/9
I thought abt that, but assumed it wouldn't work here cause circles Ig
okie that is wayyy easier :D
it's just a ratio of two numbers, you can cancel any common factors the way you usually do
even if the factors are pi
in my defense, I am working on very little sleep :')
oo okie
that makes sense
should I be worried that I don't have any decimal places-
oh true
normally if they say that, it means there's gonna be decimals, but maybe it was a mistake or just a deviation from how it normally is
in the manuals I mean
okie that makes so much sense :o
gross
or technically depending on what they expect, maybe you should write .000000 after your integer answer
yea
oh, they just mean "don't plug it into your calculator, leave it as a fraction involving pi"
ooo snazzy ok
ok that was what I was super stuck on (for now >.>), but do you mind checking some of my answers for earlier review problems?
there's like 5
ah maybe open a new channel so you can find another helper, i'm gonna take off and play video games haha
yea
have a good day!
you too, enjoy
.close
Closed by @deep dagger
Use .reopen if this was a mistake.
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.
is it true that $a^n \mod b = a\mod b$
kungulus
Try finding a counter example
Closed by @broken sphinx
Use .reopen if this was a mistake.
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.
is this answer correct?
@ionic spire yep
Closed by @ionic spire
Use .reopen if this was a mistake.
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.
.reopen
Hello, im in quite need of these 3 problems, theyre all about parallelograms.
one by one
Any help would be appreciated
This is easy tbh
crazy right
Im overthinking too much, so i dont have any progress at all
Damn yeah
which one do you want to start with
Well yea opposite sides are equal
angles*
Thats honestly the one i was wondering
yes
x+y=180
huh?
Wait let me give spme references
yes that's what i was gonna talk about regarding JIH
Oh thanks
so 97° + JIH = 180°
What about C. Thou? Do you have answers to that?
Its ok
Which question is c?
Wait ill send the problem again
Wait actually on second thought i dont need help at c anymore?
Are you guys solving thou?
Cuz i can close this now
.close
Closed by @gilded marsh
Use .reopen if this was a mistake.
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.
triangles sides will apply to each other by 1 . 2. 3 the smallest side is 3cm whats the biggest side
Apply to each other? Wdym?
If youre talking ratios, a 1:2:3 side ratio is not a triangle
i'm assuming that's referring to .. ^
Not a healthy triangle
degenerate triangle
Hey, that's mean! His mother said he was just a special boy :(
@quartz wasp
no the problem says its a triangle
huh?
Okay, what does "apply to each other" mean?
@quartz wasp
ratio
Oh
Right, then it should be pretty simple
How much bigger is the biggest side than the smallest side?
3 times?
Yes
It'll be a degenerate triangle
So, if the smallest side is 3cm, how long is the longest side?
thats wrong tho you mean the biggest triangle is 9 right there is no answer 9
so therefore theres some other way to do it
Please send us a screenshot or picture of the problem exactly as it is written
Including all context
its in anothr language
What language?
the ratio is 1 2 3 and the smallest side is 3 need to find the biggest side
As your question is stated, the answer here is 9
If that's not the right answer then something is wrong/missing
let the sides be k,2k,3k respectively, if smallest is 3 then k=3 and the longest is 3(3) = 9
So we need to see the problem exactly as it is written with context
@quartz wasp Could you take a picture/screenshot?
its in another language
Yes I understood that
As I've said though, with how you stated the question, the answer is 9
So if that's not the right answer then we need more context one way or another
There is no more context and th answer 9 is not on the answers
Omg
Im so stupid
It ment the angles ratio is 1. 2. 3.
Not the sides
As stated here
It would be a right triangle right
@quartz wasp Anyways, unless you have any more questions you can now .close this channel
30 60 90
Yeah that seems correct
Yea thanks
@quartz wasp Don't forget the .close
It's a command
@quartz wasp Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
dont know if this is relevant but this is on propositional form and i missed the class so im confused on what the a d c rows mean, can someone explain what they are to me?
@dire escarp Has your question been resolved?
<@&286206848099549185>
Looks like A is just what is written on top
It checks whether a implies b and b are both true
what about d and c?
wait before that, if this is the case, then why isnt row 2 true since there are both false
Probably not possible to figure out from the context you gave
But I don't know much about whatever you're studying
I'm only answering because no one else is
i just started discrete math for context so i guess this is like the most basic topic cause its topic 1
Because... They need to be both true?
I meant the context above the question
Look at how A is defined above
(a => b) n b is what I'm reading
Might be a weirdly written upside down U though
isnt it both true or both false = true
No?
Plus that doesn't change the fact that both false does not mean both true
I see they need to be both true
If they're both false then they're not both true
i think i mixed that up with biconditional
And the symbol they used, whatever it actually is, means "and"
like v right
No, that's "or"
upside down is and?
Yep
could the d and c mean dnf/cnf?
Closed by @dire escarp
Use .reopen if this was a mistake.
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.
Suppose $p$ is a prime and $3\mid p-1$. Prove that $$p\mid (p-1)! \sum_{k=1}^{\frac{p-1}3} \frac{(-1)^{k-1}}{(3k-1)(3k-2)}.$$
moriaritie
can i get a hint for this? plz
nvm, the question seems incorrect lol. ill ask for help later when i get the right thing
.close
Closed by @hybrid plover
Use .reopen if this was a mistake.
.reopen
✅
Suppose $p$ is a prime and $3\mid p-1$. Prove that $$p\mid (p-1)! \sum_{k=1}^{\frac{p-1}3} \frac{(-1)^{k-1}(2k-1)}{(3k-2)(3k-1)}.$$
moriaritie
alright, this seems to be right...
how do i approach this problem? partial fractions will give 2(p-1)/3 fractions only, so we can't apply wolstenholmes.
@hybrid plover Has your question been resolved?
ok ill figure it myself
Closed by @hybrid plover
Use .reopen if this was a mistake.
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.
.close
Closed by @buoyant pond
Use .reopen if this was a mistake.
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.
so guys i came across a problem which state that asuming |a| <= |b| then : min(|a - b|, |a + b|) <= |a|, |b| <= max(|a - b|, |a + b|) iff : |b| <= 2 * |a|
i know to proff this i need to proof :p -> q and q -> p but the thing is the idea that |a - b|, |a + b| can be swaped together confuse me alittle what is the right way to approach this problem?
btw the domain of a, b are Integers set
@keen pecan abs everywhere.
So as a hint, consider first the values |a + b| and |a - b| alongside the values |a + c| and |a - c| where c = -b
What can we say about these two pairs of values?
What about |d + b| and |d - b| where d = -a?
for (|a + b|, |a - b|), (|a + c|, |a - c|) they both the same pair?
no wait sorry
the first one is (max, min), second pair is (min, max) or the oposite
right?
Yup
So, the smaller of the two values is going to be whatever the positive differences in the magnitudes are
And the larger of the two values is the sum of the two magnitudes.
im sorry i think i got lost here do u mean that the max will be |a| + |b| and min |a - b| ?
i think i got it ok so next we will repharse the problem as this?
||a| - |b|| <= |x|, |y| <= |a| + |b| <-> |b| <= 2 * |a|
x, y _> a, b sorry a typo
Yup, because if |b| were larger than 2|a| then ||a|-|b|| would be larger than |a|
As an example consider a = 1 and b = 10, so our two values of max and min would be 11 and 9 respectively
oh got it its a proof by contradiction
thnx alot for the help🙏
No problem
.close
Closed by @keen pecan
Use .reopen if this was a mistake.
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.
Hello
I got majorly two questions to ask
The question is written on paper, and I wonder how to transform it into the remainder of the question required to prove, or did I approach the wrong method
Second question is that what should I do now if it seems to be 1 by ratio test
<@&286206848099549185>
( It is 100% that we gonna use ratio test btw )
@lavish wharf Has your question been resolved?
Closed by @lavish wharf
Use .reopen if this was a mistake.
.reopen
✅
<@&286206848099549185>
@lavish wharf Has your question been resolved?
@lavish wharf Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
Was solving like this.
But then saw a solution online that took tan^(-1)(tan θ) as θ.
But i remember learning, cause tanθ domain is bigger than tan^(-1)(x) thus tan^(-1)(tan θ) cannot be equal to θ
[\tan-1 = \theta + \pi k ] for some integer (k), which is covered by the (+C) in integration
cloud
you could proceed like that and get an integral that's valid only in that particular range, then

Should I keep this in mind and use it or not—
the only other possibility that i can see would be to integrate by parts from the start, which would involve a pretty hairy derivative but would be valid everywhere
what's a hairy derivative
just a bit tedious/complicated
I thought it's some shortcut like Heavyside coverup method 😅
@fallow aurora Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
.reopen
✅
@fallow aurora Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
.reopen
✅
@fallow aurora Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
my workings are:
it suffices to prove $\forall (\epsilon:R),\epsilon > 0, \exists (N:N), \forall(n:N),n>N \to \mid a_f(n) - a\mid < \epsilon$ and suppose $h:\forall(\epsilon:R), \epsilon > 0,\exists(m:N),\forall(k:N),k>m, \mid a_k - a\mid < \epsilon$
first assume $\epsilon:R$ and assume $h:\epsilon > 0$ take N=m, where m is sufficiently large. to make {$a_n$} converge. it suffices to show
$\forall (n:N) \to n > N \to \mid a_{f(n)} - a\mid < \epsilon$
assume n:N,assume $h_1 : n>m$ it suffices to show $\mid a_{f(n)} - a\mid <\varepsilon$
split the choices of n into n being odd and n being even.
so take n to be odd, so take n to be 2k + 1, where k>m. $f(2k+1) = 2k+1$ since 2k+1 is odd. it suffices to show $\mid a_{2k+1} -a\mid <\varepsilon$. since m<n, and n = 2k+1, 2k+1>m so it converges for odd n
take n to be even, so n = 2k where k>m. $f(2k) = k$ since 2k is even. it suffices to show that $\mid a_k -a \mid <\varepsilon $ since k>m, the sequence converegs for even n by $h$
this doesnt seem correct to me, but I'm not really sure why. Can anyone tell me if this is correct or if I'm miles off
lewis_f04
@wooden garnet Has your question been resolved?
@wooden garnet Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
Why am i wrong!
?*
Show your work, and if possible, explain where you are stuck.
@fluid wren Has your question been resolved?
Closed by @fluid wren
Use .reopen if this was a mistake.
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.
Hello
A few possible questions
first off im graphing the following (2x+4)/(2x-2) for example im wondering how I can use the horizontal asymptote/ vertical asymptote to graph
@timid escarp Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
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.
@junior smelt
Closed by @strange plaza
Use .reopen if this was a mistake.
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.
how do you factor and graph a polynomial with a degree of 3 while using synthetic? for example f(x) = x^3 -x^2 -14x +24
first consider rational root theorem to identify candiates to use for your division
@jovial notch Has your question been resolved?
Closed by @jovial notch
Use .reopen if this was a mistake.
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.
where does pi/4 come from next to r^3/3?
are you doing r^2 dr dtheta
that is from the outside integral, note that $\int_0^{\sqrt{2}} r^2 dr$ is independent of $\theta$, so the outside integral is like integrating a constant from 0 to $\pi/4$
smay
so the constant is 1?
the constant is the inside integral, like whatever the result is from that (which will just be a single number at the end) you’re integrating it from 0 to pi/4
so i got r^3/r | sqrt2 to 0 from the first intergral
yep
okay so then you integrate this “function” (it’s a constant function with respect to theta) from 0 to pi/4
well the antiderivative would be 2sqrt(2)^3/3 * theta, and you would evaluate that at pi/4 and 0
which makes it look like you’re just multiplying by pi/4
im confused why the theta comes from
if you intergrate over dr
oh wait
isnt the order wrong?
nvm
i got confused
well, okay we can go over what the general idea is, we evaluate the inside integral first
i got it now
oh good!
Closed by @cobalt tapir
Use .reopen if this was a mistake.
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.
I feel some information is missing
btw, you aren't cheating, are you?
i concluded that this question is solvable by quadratic eqqn
as in the value is prob found through quadratic
??
is this from an exam your writing righnt now
no LOL
it's my tutorial
either way i gotta use lockdown browser for online tests
you don't know what adot b is, neither axb, you can't find the answer afaik
use the dot product?
Think of a formula you may use.
yep that's what i did
$b\cdot a=\left|a\right|\left|b\right|\cos\left(\frac{\pi}{4}\right)=4\lambda+3$
Combustion
yes but neither a cross b , nor a dot b is given, so how is lambda even determinable
hold up let me try
= cos theta
ah yeah
yeah it can be solved
$b\cdot a=\left|a\right|\left|b\right|\cos\left(\frac{\pi}{4}\right)=4\lambda+3\to\frac{5\sqrt{\lambda^{2}+1}}{\sqrt{2}}=4\lambda+3$
Combustion
cos(pi/4)
oh
must've been because i didn't convert cos pi/4 to fraction
that would make life easier
oh my god
i saw where i did wrong
this is embarrassing ima close this 🥲
.close
Closed by @midnight dragon
Use .reopen if this was a mistake.
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.
