#help-36
1 messages · Page 127 of 1
yes?
try to look at the answer choices
ok
1 doesnt seem like a good value to plug in, as it doesnt really match any of the answer choices
yep
Closed by @vast tinsel
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.
draw a tangent line and compare the slopes
compare the slopes
Closed by @cerulean rapids
Use .reopen if this was a mistake.
np
.reopen
✅
derivative at x=1?
yeah
is it asking you to do it algebraically or from the graph?
ah ok
its multiple choice question
drawing a tangent line might be a good option, as the potential answers are quite different from each other
you can immediately rule out a majority of the options though
once you determine whether the slope of the tangent line is positive or negative
how can i know whether the slope is positive or negative?
without using the formula
by looking at the shape of the graph
if the tangent line would be sloping downwards, you immediately know the slope of it is negative
yes by the direction the tangent line is going in
it goes from the top-left to the bottom-right
-2
ye
thanks
np
.close
Closed by @cerulean rapids
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.
find % change in de-Broglie wavelength when a potential difference of 3V is applied to deaccelerate and electron with initial KE = 4eV
can you solve this using differentiation?
or error analysis
fyi
,, \lambda = \frac{h}{mv}
Aetherfly
0.2 percent
how'd you do that
Let me write it out
did you do that?
To find the percentage change in the de Broglie wavelength, we first need to calculate the initial and final de Broglie wavelengths.
The de Broglie wavelength (( \lambda )) is given by the formula:
[ \lambda = \frac{h}{p} ]
where ( h ) is Planck's constant and ( p ) is the momentum of the particle.
For an electron, the momentum (( p )) can be calculated using its kinetic energy (( KE )):
[ KE = \frac{1}{2} mv^2 ]
[ p = \sqrt{2mKE} ]
where ( m ) is the mass of the electron and ( v ) is its velocity.
Given that ( KE = 4 , \text{eV} ) and ( V = 3 , \text{V} ), we can calculate the final kinetic energy (( KE_f )) using the energy change due to the potential difference.
[ KE_f = KE_i - eV ]
where ( e ) is the elementary charge.
Then, we can calculate the final momentum (( p_f )) and hence the final de Broglie wavelength (( \lambda_f )).
Finally, we can calculate the percentage change using the formula:
[ % \text{ change} = \frac{\lambda_f - \lambda_i}{\lambda_i} \times 100% ]
Let's calculate it.
First, let's calculate the initial momentum (( p_i )) and the initial de Broglie wavelength (( \lambda_i )).
Given:
- Initial kinetic energy (( KE_i )) = 4 eV
- Elementary charge (( e )) = 1.6 × 10^-19 coulombs
- Mass of the electron (( m )) ≈ 9.109 × 10^-31 kg (approximately)
Using ( KE_i = \frac{1}{2}mv^2 ) and ( p_i = \sqrt{2mKE_i} ), we can find ( p_i ).
[ p_i = \sqrt{2 \times 9.109 \times 10^{-31} \times 4 \times 1.6 \times 10^{-19}} ]
[ p_i ≈ 3.36 \times 10^{-24} , \text{kg m/s} ]
Now, let's find ( \lambda_i ) using ( \lambda_i = \frac{h}{p_i} ).
[ \lambda_i = \frac{6.626 \times 10^{-34}}{3.36 \times 10^{-24}} ]
[ \lambda_i ≈ 1.97 \times 10^{-10} , \text{m} ]
Next, we'll calculate the final kinetic energy (( KE_f )) using ( KE_f = KE_i - eV ).
[ KE_f = 4 - (1.6 \times 10^{-19} \times 3) ]
[ KE_f ≈ 4 - 4.8 \times 10^{-19} ]
[ KE_f ≈ 3.9992 , \text{eV} ]
Now, we'll find the final momentum (( p_f )) using ( p_f = \sqrt{2mKE_f} ).
[ p_f = \sqrt{2 \times 9.109 \times 10^{-31} \times 3.9992 \times 1.6 \times 10^{-19}} ]
[ p_f ≈ 3.355 \times 10^{-24} , \text{kg m/s} ]
Finally, we'll calculate the final de Broglie wavelength (( \lambda_f )) using ( \lambda_f = \frac{h}{p_f} ).
[ \lambda_f = \frac{6.626 \times 10^{-34}}{3.355 \times 10^{-24}} ]
[ \lambda_f ≈ 1.974 \times 10^{-10} , \text{m} ]
Now, let's calculate the percentage change:
[ % \text{ change} = \frac{\lambda_f - \lambda_i}{\lambda_i} \times 100% ]
[ % \text{ change} = \frac{1.974 \times 10^{-10} - 1.97 \times 10^{-10}}{1.97 \times 10^{-10}} \times 100% ]
[ % \text{ change} ≈ 0.2% ]
So, the percentage change in the de Broglie wavelength when a potential difference of 3V is applied to decelerate an electron with an initial kinetic energy of 4eV is approximately 0.2%.
ika
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
ika
Now, we'll find the final momentum (\( p_f \)) using \( p_f = \sqrt{2mKE_f} \).
\[ p_f = \sqrt{2 \times 9.109 \times 10^{-31} \times 3.9992 \times 1.6 \times 10^{-19}} \]
\[ p_f ≈ 3.355 \times 10^{-24} \, \text{kg m/s} \]
Finally, we'll calculate the final de Broglie wavelength (\( \lambda_f \)) using \( \lambda_f = \frac{h}{p_f} \).
\[ \lambda_f = \frac{6.626 \times 10^{-34}}{3.355 \times 10^{-24}} \]
\[ \lambda_f ≈ 1.974 \times 10^{-10} \, \text{m} \]
Now, let's calculate the percentage change:
\[ \% \text{ change} = \frac{\lambda_f - \lambda_i}{\lambda_i} \times 100\% \]
\[ \% \text{ change} = \frac{1.974 \times 10^{-10} - 1.97 \times 10^{-10}}{1.97 \times 10^{-10}} \times 100\% \]
\[ \% \text{ change} ≈ 0.2\% \]
So, the percentage change in the de Broglie wavelength when a potential difference of 3V is applied to decelerate an electron with an initial kinetic energy of 4eV is approximately 0.2%.
```Compilation error:```! LaTeX Error: Unicode character ≈ (U+2248)
not set up for use with LaTeX.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.53 \[ p_f ≈
3.355 \times 10^{-24} \, \text{kg m/s} \]
You may provide a definition with
\DeclareUnicodeCharacter```
I hate compile errors
Wdym?
the correct answer is 100% increase
Wait so why do you want help for
.
Yea of course. Let me try to do it with that
oh
yes
so what does the answer mean when you differentiate?
like what does it represent
it will still be representing the rate
,, \frac{\Delta \lambda}{\lambda} = \frac{-1}{2} \frac{\Delta K}{K}
but its not accurate for large stuff
Aetherfly
no like what if you plug in all the values?
like
yes
in there
oh
u can use it upto like 10% or so
in the beginning
what if I differentiate in the first place
my ans is wrong
how do I know it
do it using the normal method to check?
or should I not use it normally
lemme tell u
@jagged 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.
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
@crisp maple Has your question been resolved?
1
Do yk the basic differentiation rules?
@crisp maple 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'm struggling to work through this problem using trig identities, I'm able to solve it using l'hopital for the sake of checking my answer but every time i attempt to expand it out i get a incorrect number
Try using that
so if you have that over cos(x) - sin(x) would you be able to simplify it to just be cos(x) - sin(x)
i wasnt actually aware you could use difference of squares with trig identities
that's good to know
it doesn't matter what x or y is. x^2 - y^2 = (x-y)(x+y)
i dont think ive ever seen an exception
Fair. I've just never taken a proper trig course so this stuff is unfamiliar for me for sure. After cancelling out things i did get the correct answer and i appreciate the help everyone
gonna close this out but it genuinely is v appreciated o7
.close
Closed by @serene smelt
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 couldn't figure out any statement, i really could use some help
@urban socket Has your question been resolved?
alr i solved the problem
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.
can someone help me with the last part please
!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
Dw
Nvm
I see why
This is tanh not tan
So it would be -tanh^2 + 1 = to sec^2
Is anyone able to help me with c?
I tried
But got no where
nope
partial fractions
Closed by @feral siren
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.
Would someone please be willing to help? At the bottom of the paper I need to factor the k*2(k^2+6k+11) /6 to be equal to the right hand side of p(k). But I can't figure it out
this doesnt factor into right side
Oh I did something wrong?
Does that make all my work useless since I contuine with the assumption that the base case was true?
it would be true for someother integer tbh
i dont think it would affect ur working too much ( i hope ) , kinda rusty at induction proofs
Dang, would you know what I should do next then?
what is ur original question
It is strange
i dont get something
why are u taking the last 3 terms in ur induction proof?
the way i done it , i only took the last term
so base case P(1)
n = n(n+1)(n+2)/6
1 = 1(1+1)(1+2)/6
1 = 1
I thought we take the whole part after the +...+
Or are we only taking the last term?
i only took last term
Ah okay
i have no clue about this , its better to close and make new channel
Closed by @late pasture
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.
lim 1/x
x->inf
0
sry i dont know that too
But if we write expansion using taylor series it's different
@storm karma Has your question been resolved?
Can you translate it?
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.
what is it meant when it says "the right sides must have b1+b2+b3 = 0? Thanks
So for example if the right side added to 0. there would be a solution?
i think i got it
.close
Closed by @fierce sun
Use .reopen if this was a mistake.
verwende satz des pythagors um dem Höhe zum wissen
alles klar
,rccw
375m^2+b m^2 = 625m^2
aha
ich wollte das bild umdrehen haha
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 need to calculate the double integral, but i need to use a change of variables to compute this. The solutions used let u = xy, v = y/x, but why do they do this specifically and how do i determine that?
@rain ermine Has your question been resolved?
@rain ermine Has your question been resolved?
@rain ermine Has your question been resolved?
they do it that way because it's a rectangle in parameter space
but how do i come up with those substitions? is there a recipe to follow to get the correct subtitution
I don't think there's a one-size-fits-all method
but for this one, it's based on the equations you're given
if u = xy, what is the range for u
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.
gui'
does anyone know w here the digits here come from
from here
I know that you should add the border lines of the histogram, but I'm doing something wrong
@thorn hollow 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.
calculate the areas?
so like area under it?
so id make a triangle from 0-4
then a rectangle from 4-6
then a triangle 5-8
or just a big trapezoid
well you don't have to calculate all of them even
some of them will be negative, right
so they'll cancel some of the positive ones
whom needs help
i got -3
me por favor
show your work
ok
area under the x axis is -13/2
average of the bases is 13/2 * 1
over the x axis is 7/2 *2
area under the x axis?
that is not true
there are only two small triangles below the x axis
i thought it was just the area
yes, the area between the curve and the axis
can you shade in what area you're calculating and show me?
@lethal estuary I think you’re wrong
only the portions between the curve and the x-axis
so just the top part?
those 3 portions
those are the parts that are between the curve and the axis
oh
i got 2
ok you think so?
this is the other one
im pretty sure its right
im just second doubting myself
looks right
Closed by @barren belfry
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.
!help
To ask for mathematics help on this server, please open your own help channel or help thread. See #❓how-to-get-help for instructions.
.close
Closed by @marsh temple
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 could I use the well ordering principle here
@fathom stream Has your question been resolved?
@fathom stream Has your question been resolved?
Closed by @fathom 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.
@shut wasp Has your question been resolved?
@shut wasp Has your question been resolved?
@shut wasp Has your question been resolved?
.close
Closed by @shut wasp
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.
Whats up guys, hope your having a good night
They want me to find the area of the shaded area
So we know 2 cm
Would I just do that with 5 cm or 5cm - 1
"do that"?
Like what numbers to use to find area
ur gonna be finding the area of two triangles and finding the difference of those numbers
find area of the total larger right triangle
remember area of a triangle is 1/2 x base x height
subtract area of smaller right triangle
Here's the whole problem they asked, Find the area of the shaded region in the figure below.
i dont think you need hypot
hehe
yea
im sleep deprived
yeah just (1/2)*bh
One second let me do some black magic
large on top
small on bottom
Give me a second cause I know thats wrong
2.71?
For shaded
em
wheres the sqrt(21) from
isnt it just 5?
cuz base times height
ur trying to find the area of the smaller triangle and subtract from larger
Aint it like 2.5?
do you still need help with this?
IS it 2.5?
uhh lemme work it out rq
big triangle has area 1/2 * 3 * 5 = 7.5, unshaded triangle has area 1/2 * 1 * 5 = 2.5
so the shaded part has area 7.5 - 2.5 = 5
actually you don't even need to subtract them lol, you have the base and height
Closed by @crystal fox
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.
Wrong place
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 need help with this meteorology problem , I know I need to use something related to stadistics but idk what exactly.
Translated Text:
Complete the temperature information series for the Jauja Station using data from the Huancayo-Huayao Station. Likewise, complete the temperature information series for the Comas Station using data from the Huancayo and Jauja Stations.
15 mins have passed <@&286206848099549185>
!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
1
@solid lark Has your question been resolved?
Bro has the me city profile
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
Yo
^^
?
That's the same formula. They were trying to write in latex
was gunna say
i dont understand any of that
still having problems w this question
18cm
for a ?
What did you multiply?
And that gives?
17.08
To 1 decimal place
It's 17.1
Yeah no problem
For the second problem, I'm not sure what B refers to
Is it the (larger) sector area or the angle?
Yeah 4.9 is right. I thought 35 was the circumference so I got confused
@paper crane Has your question been resolved?
Try again and look at the data you have
No problem 👍
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.
What is the question?
Find the area between those 2
Zoom out the diagram
You would see the two intersections
Find the area between the points in which those two points intersect
Do I have to calculate the area under the x-axes too?
No
Also
It's very ambiguous
When you don't mention what the question is asking
We could have calculated anything
Since you did not specify anything
The question is to calculate the area restricted by them
The interception points are x = 2 and x = 1
I know.
But there is a small part of area under the x-axes
You said that it's between the curves
Restricted by the curves*
So we won't really count that.
What if there was one more restriction, y = 0
Do I have to find the area between x axes then?
I'm asking about the part under y = 0
And what if there is no y = 0?
Well then it would be the integral from 1 to 2
Yes
Only that pretty small part?
Yes
Thank you very much
Please close the channel.
.close
Closed by @misty sequoia
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.
Integers:
Multiplication of integers:
Show in general that the definition of multiplication is independent of the choice of representatives from an equivalence class.
Hint: at one point add $$b'c+a'd$$ to both sides of the equation:
This was my idea so far:
$$(a,b)\sim(a',b') \wedge (c,d)\sim(c',d')$$
Def:$$a+b'=b+a' \wedge c+d'=d+c'$$
Def: $$(a,b)\odot(c,d)=(ac+bd,ad+bc)$$
z.z.: $$(a,b)\odot(c,d)\sim(a',b')\odot(c',d')$$
$$= (ac+bd,ad+bc) \sim(a'c'+b'd',a'd'+b'c')$$
$$=(ac+bd)+(a'd'+b'c')=(ad+bc)+(a'c'+b'd')$$
Benschko
@glad steeple Has your question been resolved?
Closed by @glad steeple
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.
Find the value of n if nC3 + (n+1)C2 + (n+2)C1 =72
Do you know what nCr is?
And if so, what have you tried?
ive tried the usual method using algebra but i believe the working should be substantially shorter, so i was wonder if there was a shorter method to do this question
Do you mind sending your solution?
yeah
^
Well one thing you could have done is to cancel out the factorials on the bottom with ns
That way it’s not as many variables
You could also surmise that your answer is a positive integer (because factorials are weird otherwise), so from the cubic, you could say $n(n^2+11)=420$ and then trial and error factors (clearly the second one is larger than the first, so you can minimize your guesses)
CST (please ping when replying)
But yeah the basic idea is just to find the cubic, stumble onto n=7 working, and then verifying nothing else does
Long division or synthetic, you arrive at a quadratic with imaginary roots
And then yeah discriminant will do the job there
are there any identities that can help shorten the working or is using algebra the only option?
Honestly I don’t think so
what would you cancel out exactly and where would you do it?
CST (please ping when replying)
ohhhhh
So when you add the fractions together
You only have to multiply constants to make the denominators equal
Instead of multiplying a lot of variables
yes i understand now
thank you
no problem
.close
Closed by @odd garden
Use .reopen if this was a mistake.
.reopen
✅
wait sorry i have another question im not sure about
if nCr + nC(r+1) where n and r are integers, show that n is odd
these are the hints i currently have
is it + or =?
sorry its =
try writing up the equation and then removing the n! from th enumerator
Use the formula of nCr and nCr+1, then simplify using n! = n (n-1)!
nCr = nC(r+1)
or , r!(n-r)! = (r+1)!(n-r-1)!
or, r+1 = n-r
n = 2r + 1
are those all different methods or one method?
it is sadly the complete solution, which helpers are not supposed to give outright 💀
Give me solution to my problem
sorry could you please explain the working between line 2 and 3
cancel out r! and (n-r-1)! from both sides
if you expand
(r+1)! = (r+1) x r!
similarly, (n-r)! = (n-r) x (n-r-1)!
Similar to what we did here btw
what do u have so far
have you tried expanding part i) on both sides
and rearrangig
@odd garden Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185>
Oh sorry
I didn't know that coz I joined yesterday
In the first question , try to expand and take the common elements and factor it
And whatever's left inside which was uncommon , just solve it
@odd garden Has your question been resolved?
Yea u need to do this
Use this
Write the series in expanded form
The first term is 2C2
It can be written as 3C3
As 2C2 = 3C3
Then use this formula
Add the first two terms
After adding, again the sum and the third term should come in this form
@odd garden Has your question been resolved?
Closed by @odd 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.
Remlis
$r=(3,-2)+t(-1,-4)$
Remlis
$m=\tfrac41$
Remlis
$m_{\perp}=-\tfrac14$
Remlis
$y=-\tfrac14 x+C$
Remlis
$y+\tfrac14 x=C$
Remlis
$-2+\tfrac14(3)=C$
Remlis
$C=-\tfrac54$
Remlis
Remlis
Remlis
$x+4y+5=0$
Remlis
this is wrong though
is the correct answer y = 4x - 14
you seem to be finding the line perpendicular to the given line
yeah
oh
so there was no need to find the normal to the slope
$y=4x+C$
Remlis
$-2=4(3)+C$
Remlis
$C=-14$
Remlis
$y=4x-14$
Remlis
$4x-y-14=0$
Remlis
Closed by @rich abyss
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 m e on this please? how is q in meters, if w=1s and t = s, then the quanitites dont match
$4(x+4)=17
w=1/s
You're right, I'm afraid.
If w=1/s and t=s, then e^iwt is not dimensional so unit is 1
Then ay+q has to be m/s so a=1/s and q=m/s
That's my proposed solution
I agree
Closed by @lost drift
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.
e^x - 1 is equivalent to x
isnt it 0
1-1
just like he got the 2
1+1
?
you can't be equivalent to 0 unless you're equal to 0 in a neighborhood of the limit point
how he got that 2 then
because 2 is a non zero constant
the definition of equivalence :
$f\sim_a g \Longleftrightarrow \frac{f(x)}{g(x)}\xrightarrow_{x\to a} 1$
rafilou2003
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Closed by @full halo
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 sin(theta) term is missing a square root in the denominator btw
i'm pretty sure you can't uniquely find theta from this
unless you know values of a and b
otherwise the best you could really do is like arccos(a/sqrt(a^2+b^2))
sin(theta)=b/sqrt(a^2+b^2)
or arctan(b/a)
yes but b/a need to be in ]-pi/2 ; pi/2[
.
this problem only makes sense if they give you a,b
otherwise you just write theta in terms of arccos or arcsin or arctan
I gotta do a disjunction of case
example
if $b > 0 : x \in \displaystyle\bigcup_{k \in \mathbb{Z}}[\arctan(\dfrac{b}{a})-\dfrac{\pi}{2}+2k\pi ; \arctan(\dfrac{b}{a}) +\dfrac{\pi}{2}+2k\pi]$
Akti
this is just the definition of sin and cos lol
let a^2+b^2=c^2
you can find theta with arctan
like stephen said
c=sqrt(a^2+b^2)
you have the system sin(t)=.../... and cos(t)=.../...
So sin/cos=b/a (those squares get simplified)
pretty sure you can always do this
tanx = sinx/cosx is an equality regardless of x
unless cosx is undefined
still holds it’s just that tanx isn’t continuous
at pi/2
and -pi/2
and just odd multiples of pi/2 of course
so I gotta do a disjunction of cases if cos(theta)=0 ie ... ±pi/2+2kpi... and the rest of x values ie x=arctan(b/a) ?
@sonic bloom 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 solve this problem?
Closed by @hushed apex
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.
It says Factor the polynomial by factoring out the greatesy common factor, x+2. how do I factor a polynomial?
Renz
y is common so factor that out
wait
,,y(x^2-4)=0
where did you get that equation from?
Renz
and y is x+2 so you just put that back in
im still confused.
wait so to make it easier for myself I just imagine this into the equation.
no its still not making sense to me
(a)(x)-(b)(x)
I did not take intermediate algebra, I jumped into a college algebra class after a 5 year hiatus.
You factor as x(a-b)
If you expand this you will get the initial
x * a - x * b = ax-bx
you remember how to expand right?
@restive badger Has your question been resolved?
barely
Closed by @restive badger
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.
what is positive 3
dot product between (x,y)1 and (x,y)2
it is negative though
oh the cosine
yea
yeah should be negative
/ratios
yeah okay acute angle
seems wherever it's negative they flip it positive
but wherever it's positive they keep it positive
but isn't that relevant
for the theta value
if you draw two intersecting lines you will find one acute and one obtuse angle
you're only being asked the acute angle
acute means positive?
the cosine is positive yes
<90
Yeah correct
Closed by @rich abyss
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.
Basically I have to find the volume bounded by the function Z, bounded by y=5 and they also bounded by the first octant
Can anyone verify my double integral?
.close
Closed by @quiet ivy
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 think the ans key is wrong, i got 5 as the answer
but i didnt get any sleep last night so i might have done it wrong
show your work please
im on my pc, but ill try to send it one moment
that's correct
5 is the answer?
yes thats what i got, the answer key says 0
yeah it should be 5
I'm assumimg answer key did pi instead of pi/2 by mistake, if I had to guess
Closed by @empty wharf
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.
"Calculate the flow integral ... where S is the mantle surface to the paraboloid and N is the inwardly directed (with positive z-component) unit normal. Is it possible to close the closed surface and use Gauss's theorem as in the previous problem?"
i have calculated ∇ * F = 0 and the top and bottom disks are z = 24 and z = 12. i have calculated 1/(x^2+3y^2) [-3y, x, 1] [0, 0, -1] = -1/(x^2+3y^2)
and we have x = rcos(theta) and y = rsin(theta). and from x^2+3y^2 = 12 and x^2/12 + y^2/4 = 1 we get the permetarization (2sqrt(12r)) and we have the bounds 2pi to 0 and 1 to 0
so what exactly am i supposed to integrate?
@proper yoke Has your question been resolved?
<@&286206848099549185>
@proper yoke Has your question been resolved?
@proper yoke Has your question been resolved?
Why did you calculate ∇ * F = 0?
that what is became -6xy/(x^2+3y^2) + 6xy/(x^2+3y^2) + 0 = 0
F(x,y,z) = (-3y/(x^2+3y^2), (x/(x^2+3y^2), 1/(x^2+3y^2)
hmm
no you can't just 'close' the surface, cuz then it's a different surface. And since it's not closed you can't use Gauss Theorem. The way to evaluate the integral is by parametrisation:
$\int \int_{S} \textbf{F} \cdot \hat{\textbf{N}} \ dS = \int \int \textbf{F}(\textbf{x}(r, \theta) \cdot \left( \frac{\partial \textbf{x}}{\partial r} \cross \frac{\partial \textbf{x}}{\partial \theta} \right) \ dr \ d\theta$
lgkoo
yea
I don't think that answers the question why you calculated $\nabla \cross \textbf{F}$
lgkoo
also, note that the top and bottom of S is an ellipse, not a circle, so the parametrisation for (x,y) is not rcos(theta) and rsin(theta)
the method looks right, you just need to fix the parametrisation
Oh really what wrong
as I said, rcos(theta) and rsin(theta) is the parametrisation of a circle, not an ellipse. The diagram should also be ellipses
Oh okay
well it just changes by some factor 3
still looks like a mess to solve
fuck
,,\vec{s}(r,\theta) = \begin{pmatrix} \sqrt{3}r\cos\theta \ r\sin\theta \ 3r^2\cos^2\theta + 3r^2\sin^2\theta \end{pmatrix} = \begin{pmatrix} \sqrt{3}r\cos\theta \ r\sin\theta \ 3r^2 \end{pmatrix}
sqert(3)
lemme make you feel worse; you also forgot the 3 in front of r^2 sin(theta) 
yes
𝔸dωn𝓲²s
Ohh
Do we need to normalize the the normal vector?
no
is there a reason
yes, lemme see if I can find, cuz I've shown that proof to my friend before our amv test
so the norm cancels out
yeah
nice thanks buddy
np
What is an amv test?
amv stands for analysis in many variables in my uni
which is just second year calculus
Ohh that does not sound fun
no it's a lot of fun
way better than theoreotical modules like
probability and algebra
those are so pure
Closed by @proper yoke
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.
!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
I got -10 and -1 as the answer, so number of solutions is 2
I need someone to confirm that -10 and -1 are the answers please
well apparently -1 isnt valid according my textbook
Well, it should work (unless they're doing something weird with their notation), after all sqrt{x^2} is just |x|, so the right hand side becomes log10(1) = 0, as does the right side become sqrt{log10(1)} = sqrt{0} = 0 
@empty 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.
im not sure how to do this
How are points of inflection defined?
second derivative = 0
Alright, and can you find the second derivative of g here?
Do you know what the first derivative of this g is, at least? 
well it shows an integral sign so after you take the integral you have to take the derivative again?
Well, I mean you could, but you should ideally remember the FTC 
wahts that
That if you have the function $F$ defined by $F(x) = \int_a^x f(t) \dd t$, that $F'(x) = f(x)$
@tulip coyote
well wouldnt that be the case if thre was a d/dx next to the integral
How do you mean, as in that $\dv{x} \int_a^x f(t) \dd t = f(x)$?
@tulip coyote
okay im getting confused
Alright, as a tl;dr of the FTC, it's saying that if you're differentiating something like your original g in the question, you just take the function you're integrating, replace the t's with x's, and then take that as the derivative of the "integral function"
Basically but remove the integral sign too, you just have $g'(x) = x^2 - 5x - 14$
@tulip coyote
Closed by @molten roost
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 do this
So for the lower tail, you found X <= 5 as the critical region, right? And the probability of being in that region as 0.0232578...
yes
im pretty sure
What about for the upper tail? Did you find anything for that?
uhhh