#help-19
1 messages · Page 60 of 1
just remember that n_1 must be a greater number than n_2
because total internal reflection cant happen from less dense to more dense
only vice versa
so n_1 must be 1.52 and n_2 must be 1.34
θ_2 is 90 because we want critical angle
and then you solve
no problem
would u have any idea why the mark scheme has the solutio nas this
they both give the same answer
ngl, i hate this notation lol
it's basically the same thing, but i prefer to use snell's law
since imo, it's clearer what's going on
this is kinda ugly imo, since they dont leave everything in variable form
also, i actually didnt know that you could calculate the refractive index between two materials by taking the ratio of their refractive indicies wrt air/vacuum
i suppose that's what you were confused about earlier
my apologies
but it really is the same as snell's law, and i highly doubt your instructor would take marks off if you used snell's law instead
again, it's the same as snell's law
they derived it from there
n_1sinθ_1 = n_2sinθ_2 becomes n_2/n_1 = sinθ_1/sinθ_2
n_2/n_1 = 0.8816 and sinθ_2 = sin90
they let θ_1 = C
again though, i highly advise leaving everything in variable form if you are comfortable with it
it makes solutions much clearer, and easier to follow
plus, you're less likely to make mistakes, and more likely to understand the principles better if you do it consistently
does that help? @hearty cape
if you're done here, don't forget to close the channel
how i do that
Closed by @hearty cape
Use .reopen if this was a mistake.
.reopen
✅
actually i have anthoer question 💀
go ahead
ah, this one may be out of my area of expertise lol
i'm not too familiar with complex numbers
its just like normal loci
okay, we have two conditions
the first thing is a circle with radius less than or equal to 4 and centre 0,2
yes
and the 2nd thing is a perpendiculr bisector through the middle of the points
between -4, 1 and 0, -1
with it being less than or equal to -4, 1 ?
idk what that means
hmm
"the distance from the origin to z + 4 - i must be less than or equal to the distance from the origin to z + i" is what i'm getting
but please dont take my word for it lol
perhaps someone else can help with this one?
does @ everyone actually ping everyone
na lol
aighty
if not, you can ping @ Helpers (no space) after ~15m have passed
could it be the distance from the point to the perpendicular bisector is closer to z + 4 - i than to z + i
<@&286206848099549185>
.
@hearty cape Has your question been resolved?
@hearty cape Has your question been resolved?
@hearty cape Has your question been resolved?
@hearty cape Has your question been resolved?
@hearty cape Has your question been resolved?
So it seemed like you already figured out the first equation is a circle and the second equation is one side of a perpendicular bisector. That's correct.
You can read the second equation as saying "The distance from z to (-4, 1) is less than the distance from z to (0, -1)".
So shade in all of the z where both z is inside the circle and also that's true.
Does that make sense, or are you confused by something?
<@&286206848099549185> can someone help me please
This is someone else's channel, please don't interrupt it
Please read #❓how-to-get-help
oki
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.
You have to use logarithms, you familiar with them yet?
hint $\frac{1}{2\sqrt{2}} = \frac{1}{2^{3/2}} = 2^{-3/2}$
artemetra
I think if you put both to the log_4 it should give you 3x - 2 = log_4(1/2sqrt(2)
it's fine, just roundabout
basements?
did you mean bases
Like 2^x=2^1 and you get x=1
This would be a little bit more useful if they had the same base
yeah you meant bases
they can get it
$4^{3x-2} = 2^{2(3x-2)}$
artemetra
👍
Number in some root equal to the same number with another root if only their roots are equal
√2/4 make it base 2 somehow
√2
What it is
It is 2^(1/2)
There is a rule
Lemme find
like this
yes
so you can say that 4 is 2^2 isn't it
so do 2^(1/2)/2^2
Do division
Sorry
I wasn't here lol
When you divide number with same bases
What you do
Nah, never use calculator
we need algebra
Do you know
a^b/a^c=a^(b-c)
What you'll get
nah
b is 1/2
c is 2
Yess
Yes
Do it
Yes
1/2-2
Is it hard
Yes
Number in some root equal to the same number with another root if only their roots are equal
Like 2^x=2^1 and you get x=1
Can you understand
So what's next
write your new equation
.
.
Can you do it and understand?
Yes it's good
So
Then the "powers" have to be equal
So it's linear equation
I hope you can do it
Hm
Yes
Closed by @neon perch
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.
2
!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.
if the angle is opposite the shorter side than there are always 2 triangles
he said the question
he said it in a strange way
oh lol didnt see that
like this
you can change the position of the shorter side (a) and still have a triangle with those 3 conditions
no
you said sine of a is 30
sin is to do w the ratio of sides so idk how it is equal to an angle
in the future always send a picture of the question
which board?
@remote dawn
ooh
no lol
high school
lol
use sin rule
so how many triangles possible?
i gtg
srry
just use sin rule
there is 2
Closed by @remote dawn
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 equation of a line passing thorugh P which meets the given conditions
so according to the tutor, the answer to first is y=-3,z = 4
but trying it on desmos 3D and geogebra , does not give anything close
Am i writing the equations wrong?
the comma dosent work
i am new to 3d desmos so maybe i am missing something
this is eating me alive ffs, am i being taught wrong, is the grapher wrong
and how on earth
do i do that
let me google
not yet
i mean
from what i was taught
correct madam
the guy said d2,y,d1 is the eqn of the line
actually, just take the entire pic
YES
has this something to do with y=z= lambda ?
AH i see what u did
smart
i like this
whats wrong with the thing i wrote tho
and why cant i just add a comma
ah i see
is there a calc which works with what i wrote
i can see why
oh
that interesting
thank you so much for helping, wait i have another doubt
why does this work then
i get a line ||el to x axis and passing through the point
actually
wait
dont answer it
i will find it myself
didnt see
thanks
you were so helpful
.close
Closed by @wide jackal
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.
Could balanced base 3i work?
Hmm
Just 0, 1, -1, i, -i doesn't seem to do it
Wait why would the digits not all be real
wait, (3i)^n is complex of course
Do you just want to represent integers?
or extend it to the complex integers as well
@dull light Has your question been resolved?
Then you probably need all 9 of them
This might be one of the worse ways possible to count
@dull light Has your question been resolved?
Do the integers have unique representations
Yeah, I think so
The quater-imaginary numeral system is a numeral system, first proposed by Donald Knuth in 1960. Unlike standard numeral systems, which use an integer (such as 10 in decimal, or 2 in binary) as their bases, it uses the imaginary number 2i (equivalent to
−
4
...
Actually, you might need 17 digits
17?
No, that's only if you use purely imaginary and purely real ones
Yeah, you have the even powers of (3i) and the odd ones
Congratulations you found a worse way to count
but it seems like you can cover the complex plane with just 9 digits if you include complex ones
$$15 + i = (i) \cdot (3i)^0 + (i) \cdot (3i)^1 + (1) \cdot (3i)^2 + (-1) \cdot (3i)^3$$
Jelle
As an example
Do all reals have a unique form?
Yeah, wait maybe the thing is that all the digits are supposed to be real though
Iirc they don’t in balanced base 3
They do, right?
I think it was something like 1.TTTTT…. = 0.11111…
Yea but that’s not what being written
I could be wrong but that might of been 1/2 if I remember correctly
Oooh, btw if you only use real digits you still need 9 digits. This was incorrect
Wait then you can use just 3 digits in base sqrt(3)i
No, because only the imaginary part has integer values
@dull light Has your question been resolved?
Closed by @dull light
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.
Gaussian integral?
whats that
Closed by @graceful berry
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 derive the formula for the sum of this series? I can differentiate and integrate, but I don't understand how to derive formulas for sums.
Also, if anyone knows any good sources on finding the sum of series, I would like to ask for a link to it.
(books, videos etc.)
I didn't find anything in my native language 😦
@minor ice Has your question been resolved?
Can we find the sum of each series by differentiating and integrating? Are there any series whose sum cannot be calculated?
@minor ice Has your question been resolved?
Closed by @minor 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 to show it is Darboux integrable
I want to split it into two intervals
[a,c) and (c,b]
but I don't know how to show that it will be integrable on those two intervals
if it was [a,c] and [b,c] I could do it😅
am I approaching it wrong?
@mellow socket Has your question been resolved?
<@&286206848099549185>
.close
Closed by @mellow socket
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.
do you know about completing the square
i tried to watch videos and understand but i dont really get the image
i can try and explain
if you wanna
yes
go ahead
okay so
[
(a+b)^2 = a^2 + 2ab + b^2
]
do you know of this
expanding the bracket?
yeah pretty much. I just want you to keep it in mind
so like
a quadratic is usually given as $ax^2 + bx + c$ right?
yes
alright so we let's make the assumption that a = 1
we now have $x^2 + bx +c$
so the idea behind completing the square is that we want to get SOMETHING that will get us something similar to this
so its just factorising?
not really. I'll get to that
so like
okay so
lets ignore the c for now (its still there but we dont want to look at it now.
alright
we have [
\c b{x^2} + \c g{bx} ]
and our square above was [
(a+b)^2 = \c b{a^2} + \c r 2 \c g{ab} + \c o{b^2}
]
now compare the first one with the second
what do you think is missing in the first one?
that the second one has
colour
they look exactly the same
wait these two?
yeah
I colour coded the similar items
hm
like the orange b^2 is not there for one, right?
and the red 2 is not really clear
yeah
a^2 is kinda there with the x^2
so okay great
we know we want to get something similar to (a+b)^2 but the problem is that we are lacking an apparent b^2 and the red 2
whats an apparent
now this is the crucial part and i need you to concentrate
okay
so lets deel with the 2 issue
in our equation [
x^2 +bx ]
there should have been a $2bx$ instead of a $bx$, but it's gone
what do you think turns 2bx into bx?
like, what do you do to go from 2bx to bx algebraically?
divide by 2
yeah exactly
so again, notice how we have x^2 correspond with a^2 right?
so that means x = a, right?
yeah
yeah but what about b?
what do u think it should be
remember like
it must be 2ab, but it transformed into bx
so hmmm
[
2ab \to bx
]
what do you think the second 'b' should be for this to make sense
2
nope! i think its an issue with them being the same letter
let me redo this for you
we have [
\c b{x^2} + \c g{bx} ]
and our square above was [
(c+d)^2 = \c b{c^2} + \c r 2 \c g{cd} + \c o{d^2}
]
what do you think b should be for this to make sense?
remember c = x
and we have x on both sides
so...
b^2
nope
hmmm how do i explain this
okay another approach
we know that c = x here
yes they are the same
we have [
\c b{x^2} + \c g{bx} ]
and our square above was [
(d+d)^2 = \c b{x^2} + \c r 2 \c g{xd} + \c o{d^2}
]
so now
bx and 2xd
the first one we have a 2 missing
what do we divide with to make 2xd be xd
2
yeah
so 2xd/2 = xd
so after we divided by 2
we get bx and xd which means b = d
but like
we had to divide by 2 for this, so there is something we need to compensate for as well
another way to look at it is this
[
x^2 +bx = x^2 + 2x\f b2
]
right? @mystic saffron
yes
so like
c^2 + 2cd
x^2 + 2xb/2
what is c equal to
and what is d equal to
d=b
c=x
nuh uh
like okay
c^2 = x^2
so that's cool
so we are left with
2cd
2xb/2
we know that c = x
so like
2xd
2xb/2
so like, what do u think it should be now
what is d equal to
2d
no
wait
d = 2
my brain is fried
yeah i think you need to take a break
give this a look later
if you want
yeah i think thats a good idea
thank you for trying to explain it to me in 5 different ways when i didnt get it😭
have a good day
.close
Closed by @native spear
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 am trying to understanding laplace transformation of heaviside function. What's bother me why we including terms from the intervals when t < a into when t > a. For example, in this example, we're adding and subtracting t why?
reference: https://tutorial.math.lamar.edu/classes/de/StepFunctions.aspx#mjx-eqn-eqeq1
for example here why we're taking g(t) to have t+5 as input rather than t-5?
@dusk rivet Has your question been resolved?
@dusk rivet Has your question been resolved?
@dusk rivet Has your question been resolved?
they include those terms cause they want a single expression for f(t), thats why they use heaviside functions
the include a -t term so it cancels with t when t>=6
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.
The three sides of the triangle are the adjacent, opposite, and hypotenuse, right?
Which one would the 50 cm side be?
Adjacent, opposite, or hypotenuse?
Please don't give out answers
(User got banned anyways)
.close
Closed by @warped grove
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 @lusty garden
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.
hi
can anyone help me

I'm assuming you've already proved that the two triangles are similar. What does that imply about the side lengths of the triangles?
The sides are proportional
Yup. Which sides, in this case?
be and ec
What's the side of triangle ABC that corresponds to the side BE of DBE?
Yup exactly
And then what's the side of triangle ABC that corresponds to the side ED of DBE?
Yep! perfect
so the relationship between AC and ED is the same as the relationship between BC and BE.
ah
Can you write an equation describing this fact?
yeah something like that
what is E?
E=42
Yeah, what do you mean by the letter E though?
No, BE is 28
yup! perfect :)
Thank You So Much
no problem
@wispy elm Has your question been resolved?
Closed by @wispy elm
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.
<@&286206848099549185>
@midnight jasper Has your question been resolved?
what progress have you made on this problem so far?
AHhh someone finally.. I really havent made any progress thus far. I think im mostly stuck on how to begin
essentially, what this problem wants you to do is take the two given approximately normal distributions and subtract one from the other, resulting in another normal distribution
does this concept sound familiar to you?
so like subtracting 1 mean from the other?
yes that's part of it
Sorry for taking a while to respond.. can we also subtract the standard deviations?
no worries
but no you cannot
the procedure for combining standard deviations is sqrt(A^2 + C^2)
I got .7976
this is what i get, and yes it is still a normal distribution
that's also what i get so i believe this is correct (just make sure to round when inputting your answer)
very nice
Thank you for being patient and helping me through out the problem! I understand the concept a lot better now. Hope u have a great rest of ur week
.close
Closed by @midnight jasper
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.
can i rewrite -log5 as log5^-1?
Log(5^-1) yes log(5)^-1 no
$-\log(5)$ as $\log(5^{-1})$?
Ann
yeah its correct
OH
YAY
ok but rewrote log9^3 - 7log5 as log((9^3)/(5^7))
and then did (log(81/5))/log((9^3)/(5^7))
thats fine
,calc (log(81/5))/(log(729)-7log(5))
Result:
-0.59580185995785
no problemm
Closed by @terse pike
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.
Left is my work and right is answer key. I checked my answers with online calculator and I think the key is wrong. Is there something I'm missing? (I'm doing bad in the class so I'm very unsure of myself 😭 🙏 )
left is correct on both
Closed by @spice spindle
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.
homework help
!show
Show your work, and if possible, explain where you are stuck.
@delicate orbit 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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
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.
revisiting vectors; came across this notation
what does it mean to 'dot product by 'i' '
right, so i should interpret i in vector calculations as (1, 0, 0 ...), j as (0, 1, 0 ...)?
makes sense
Yes
i,j,k with hats are notation for the standard basis in R^3
dunno if that applies to F^3 in general
Closed by @wheat raptor
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.
2 questions did i do this right, and is that a quadratic function?(running late on my school project ahahaha
That doesn’t look correct
-2x-2x is not 0
Slso, (-2)(-2) is not -4
Do all the steps again
yeah i forgot bro
btw you can use difference of squares
y = a^2 - b^2 = (a-b)(a+b)
the a here is x-2
and the b here is x
Closed by @vital crane
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.
Sorry for this very stupid question but where did I go wrong here
the derivative of the first one is a multiplication, so then we use the f(x)'*g(x)+f(x)*g'(x) no?
which should give us 1cos(x)+x*-sin(x)
doesnt that mean we end up with cos(x)-xsin(x), aka cos(x)+ (x*(-sin(x)))
it seems correct
but wtf
i looked up to the 3rd derivative
seems all fine
they want it to be this
ohh thats another thing
that is with taylor expansion probably
do you know the taylor expansion?
my brain is fried to the point where i took the 2 to the nominator instead of the denominator
well ish
f(x) = f(0) + f'(0)x + f''(0)x^2/2! etc
but with taylor expansion i think you do
f(x-a)
and replace all the x's with a instead
cos can be represented as 1-x^2/2 etc
you can also directly input a
without the x
no sorry
you set the a as zero in this case
and you just get x
and you get this
then multiplying by the other x you get your photo
and you can derivate that to get an approx of the derivative
but your method is cleaner
but i feel like im not getting the right answer here q.q
might be faster to use taylor if you have many derivatives of derivatives though
hm
that is always going to be 0 no?
you know identities?
what kind of identities?
limit identities
like sinx/x as x goes to 0 is 1
thats the key here
with some manipulation
i'll try it aswell
are you allowed to use l'hopital
i'll say no, because for some of the exams they do let us but sometimes they dont q.q
okok
ok i solved it with just identities
a bit of a silly solve but it works
it equals 1 right?
huh
i might have done an error myself
huh im sure its one
let me check on wolfram alpha
it is 5/6
id try to use taylor then
if you are allowed obviously
Closed by @sick sigil
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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
The formula circled in red is what I need to show is the green circled one
I would like to get my work checked so far
!msgdel
The original post of this help channel has been deleted, and it will abruptly close and possibly lock. (This is irreversible.) Please claim a new channel, and don't delete the first message of any future channel you claim.
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.
for 10(a) i had to find how to split it into 2 right triangles by testing the 3 configurations with the pythagorean theorem, in the end I got to A = 420 which is right but it took a good amount of calculation
is there a trick I'm missing or do you really have to try all 3 configs
or is there something completely different/easier I'm missing other than splitting it into 2 right triangles
trigonometry to find an angle and then use area = 0.5(AB)(AC)sin(BAC)
but there might be an easier way
i guess it's just like
splitting it into two right triangles isn't even that easy but yeah
@urban atlas Has your question been resolved?
there is not much calculation actually because it is all pythagorean triple ratios
the easiest way to find the area of these triangles aside from splitting them into right triangles would be to apply heron's formula
but the right triangle method is fun and actually takes less time if you use it well
I don't get the pythagorean triple ratios thing
I know what you mean but first it's not really clear to me which configuration of the split I'd go with and then even if I somehow knew, (now that I do) I still don't see how ratios give me the answer without doing the math
I know one of the right triangles has hypotenuse 56 and the other hypotenuse 39
what about cosine rule to get one angle then the 1/2 * sin a * bc
👀 that is extremely not fun and will take much more algebra than you want or need
yes you'll probably have to play around with it a bit
well I guess the problem is just more tedious than it seems on the surface 🤷♂️ was just making sure I wasn't missing anything
i hv no clue abt heron’s formula thats why
the second one 10(b) is a lot more obvious in my opinion on what you're supposed to do
no it is not tedious
but yes it doesn't seem you missed anything 👍
can u help me!
i see
.close
Closed by @urban atlas
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.
Can someone help with these?
this is a question about summation notation / big sigma notation
do you know what that is
idk much
surely you were introduced to it in the recent past...?
like, you've even got the fancier version of it here
where you are summing over a set
I know how to do these types
ok right.
let's look at the first sum. the one that says "i in [5]" under it
[5] means {1,2,3,4,5} (generally, [n] is the set of all natural numbers up to and including n)
so $\sum_{i\in [5]}$ is synonymous with $\sum_{i=1}^5$
Ann
ah so the first one would be 30 because 2 + 4 + 6 + 8 + 10?
$\sum_{i\in{3,6,9}}$ means there are three terms: one for $i=3$, one for $i=6$ and one for $i=9$ (and no others, only specifically these)
Ann
yes
then this would be just 3 + 6 + 9 so 18?
yes
Oh the answer is 12 ig
oh its not that bad
the last one is a bit confusing tho, how would u go about it?
@grim stream Has your question been resolved?
@grim stream Has your question been resolved?
Closed by @grim stream
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 there a semiprime between each square number? Starting at a large enough square?
@onyx nacelle 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.
I have to factor this term
I understand the first step in which I have to convert x(y-z) to xy-xz, but unfortunately I don't understand the second step in which I have to convert -(z-y) to (y-z). I would like to know how to convert -(z-y) to (y-z), nothing more. Thanks.
$$x(y-z)-(z-y)=x(y-z)+(-(z-y))$$
$$x(y-z)+(-(z-y))=x(y-z)+(-z-(-y))$$
$$x(y-z)+(-z-(-y))= x(y-z)+(-z+y)$$
$$x(y-z)+(-z+y)=x(y-z)+(y-z)$$
FirstNameLastName
@fathom bolt anything unclear?
[(-(z-y) = -1(z-y)] this is essentially by definition of the notation. then you can distribute the multiplication
thank you very much
cloud
.close
Closed by @fathom bolt
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.
Could someone please help me find the issue in my calculation
Question is:
Find the primitive function to f(x) = x+10/x^3 + 4x^2+5x
So first off I took out x in the denominator
And then I use partial fraction decomposition to get 2/x + -2x-7/x^2+4x+5
so the primitive to 2x is 2ln(x), so that one is now done
then i find the square for x^2+4x+5, which is (x+2)^2+1
i then split them up into two
and use a variable exchange on the bottom to get t^2+1
and from that i get -2t/t^2+1 which is the derivative of ln(t^2+1)
only one im unsure on is the arctan (is it legal to take out the -7? i think it is since it's a constant), but thats not even the one im having issues with lol
u went wrong when substituting x + 2 = t
why/where is it wrong?
small error lol
Closed by @sick sigil
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.
can anyone help me
! show
Show your work, and if possible, explain where you are stuck.
ok....
so without leak it takes 30 mins
with leak 45 mins
so an extra 15 mins is being added
so ye
im thinking 15
@quasi sparrow
sanity check on why this is wrong: if it took 15 minutes to empty, that means the leak empties the tank faster than the pipe fills it up, so it couldn't be filled with a leak
They pretty much told you you were wrong.
it's been 1 minute calm down
ok sorry
I can see that your answer is wrong, I just need some time to double check that what I'm thinking actually works to give the right answer
ok.....
In a single minute, the pipe would fill 1/30 of the tank. In the same minute, the leak removes a certain proportion as well.
with the leak, 1/45 of the tank is filled each minute
so the amount the leak removes a minute is the difference between 1/30 and 1/45
@paper moth 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.
hey i need some help
In this video we prove by induction that every graph has chromatic number at most one more than the maximum degree. Odd cycles and complete graphs are examples for which the chromatic number meets this upper bound exactly. For other graphs, Brook's Theorem tells us that the chromatic number is at most the maximum degree. We will prove Brook's...
4:16
specifically, why is the last line true
@blazing onyx Has your question been resolved?
@blazing onyx Has your question been resolved?
What's the question?
@blazing onyx 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 do I use a=pert to solve this?
well what are you trying to find
you have the amount of money they want to get, the time, and the interest rate
I think P?
yeah
So my equation would be $8000=pe^5.052$
micock
The problem is that I did e^5.052 and after subtraction it still wasn’t right
Don’t I multiply 5 and 5.2
Yeah
but this is e^ab
Oh
e^a times e^b is e^(a+b)
i believe
but its a product
so you should just multiply the stuff in exponent
Closed by @plucky fiber
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.
Hi, maybe a dumb question but i don't get the logic they're utilizing here
what's b?
Ax = b
where b is the solution vector ig
the context is probably only that picture tbf
for each column we make the leading nonzero a one then we eliminate all rows below it right
yes
so that's n row order operations to do it once. but there are n variables in each row as well so that's n^2. but for b it's only n
then you repeat it for the second leading nonzero etc, generally you do it n times, so it'll be some factor of n^2
hm?
i'm confused, maybe i should just write out what i think and then you could maybe help me point out the flaw with what i have in mind i guess
if b is a n x 1 vector then to change the element in the second row is 1 operation
u repeat that for everything below
so you have a sum of 1's n times which is just n
i don't see what else is there to do with b besides that
oh
it's just because you perform all the normal row operations on the matrix to get rref
and you repeat those on the augmented matrix as well (A|b)
you are just doing the rref on A and repeating the same operations on b. not doing rref for b
if you on the other hand were doing rref for b then it'll simply be 0 or 1 as there's only one column. and yes. also n operation
so you mean when i'm eliminating one row then that's n operations on b too?

oh wait, i guess it's more like this:
you mean like if i'm eliminating all the first elements in the first column
then that's already n operations on b right?
then i have to do it with the second elements in the A matrix which is n-1 operations on b and then so on?
and then sum from k = 1 to n of k is approximately n^2
okay i guess that makes sense
idk i didn't really do the math but it's some constant * n^2 probably
i'm not doing the math either
yesh
•⩊•👍
@pearl patio Has your question been resolved?
Closed by @pearl patio
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.
a bit shoddy but yes
Closed by @polar arrow
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.
Domain of √5-4x-x^2+ x^2 log(4+x)
≥
Ah ok
4+x > 0
Closed by @outer saffron
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.
0 to 3 integration √x (dx)^3
What is dx^3
