#help-39
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Thank you so much
Thank you everyone
Will close the channel
Wait i forgot how to close
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I need help drawing the diagram for this problem. I can’t seem to visualize it
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can somebody please tell me how to solve these type of questions where there is exponential function too
∞
the whole square thing and the e^x seperately?
ig it will get more ugly
$\frac{(x+2)^2}{(x+4)^2} = \frac{x^2+4x+4}{x^2+8x+16} = 1 - \frac{4x+12}{x^2+8x+16}$
Ann
e^x is still in it's multiple. What about that?
You can "long-divide" that fraction (i.e. just write x + 2 = x + 4 - 2) to get (1 - 2/(x + 4))^2, multiply that out and now Ann's IBP idea should work because the derivative of 1/(x + 4) is -1/(x + 4)^2 so you can view the last two terms as what the product rule gave you for (e^x/(x+4))'
Let's see if that works out
[\int \l(1-\frac{4}{x+4}+\frac{4}{(x+4)^{2}}\r)e^{x}dx] is what you have after multiplying out, i.e. [\int e^{x}\dd x-4\int \frac{e^{x}}{x+4}\dd x+4\int \frac{e^{x}}{(x+4)^{2}}\dd x] and now if you set $g(x) \coloneqq \frac{1}{x + 4}$ you notice that those last two terms are [-4\int e^{x}f(x)\dd x-4\int e^{x}f'(x) \dd x=-4\int e^{x}(f(x)+f'(x))\dd x]
Kepe
and that thing in the integrand is what you get after using the product rule on [...]
and then you are done
e^x * f(x) + e^x * f'(x)
yea
so integration of this thing is e^x*f(x)
Yes
i seee
But also you can just IBP on the second line as Ann said and then you don't have to do this
IBP is just based on the product rule
IBP'ing this thing should probably also work
the thing that you subtract should exactly cancel that third integral and you remain with your uv-expression
that third integral is cancelled yes
damn i am not used to these exponentials but thanks
when there is e^x you kind of automatically think of IBP
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my first reaction was g(x)=x/x-4
@void estuary
g(x)+g'(x) = ((x+2)/(x+4))^2
*e^x
=(g(x)*(e^x))'
answer can concise
wait just a min
how?
ohh
so you manipulated this into (g(x) + g'(x))
right?
yep
you did well
the answer is concise
but as a person who is not much friendly with exponentials i had to go step by step and see how things work
That's no problem, I'm just providing a better solution
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how do we know that all terms in the Sigma are intergers
ahh tyty
ig thats the reason why we have to multiply by q^n-1 at the start makes more sense now thanks
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in this definition of a sub field
for the first condition
k' + sub group of k +
shouldn't a and b be in K' not in the whole K?
guys help 1 plus 1 how much does it come out
$\forall(a,b) \in \mathbb{K}^2, a-b \in \mathbb{K}'$
Drk
$\forall(a,b) \in \mathbb{K}'^2, a-b \in \mathbb{K}'$
Drk
basically is it the first or second one?
please move to another channel
Drk
I agree
I think it's just a typo but it should be (K')^2
i mean the whole point is closure and the inclusion of an inverse
thanks edward i thought i was bugging out
this professor is incompetent
shm
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I think I need to relate radii & distances to tangent length
but I don't know how to do that
once I have that I just run it for [1, 18] and sum
I drew a diagram but I see nothing useful from that
Probably
The circles are x units apart, does that mean their centers is x+12+9 units apart?
No sure there's a better way than calculating the tangent equations for both circles and solving for a common one, something like that: https://www.desmos.com/calculator/xpvlic6zmm
There has to be another way
this is a geometry competition, the assumption is that you have 1 semester of precalc knowledge
so i doubt it would have a derivative
also, this is question 6/20
it isnt always perfect, but test designers are supposed to put easier questions first, with 20 being the hardest
so this should be a really easy problem...
but it sure doesnt seem like it
Ok but in competitions, most questions require knowing some kind of trick...
I know some but clearly not enough for this one
You may have better luck in https://discord.com/channels/268882317391429632/433980473367330826
I just tried googling "relate distance between circles and their radii to external tangent length"
and this result seems promising...I'll try it out. Maybe I should've checked google in the first place lol
ok so answer key says 16
I find the values of x and 7 & 17
so i think the answer should be 24
unless i made a mistake here
It's not x^2
,w sqrt((x+21)^2-3^2) for x={1,2,3,4,5,6,7,8,9}
,w sqrt((x+21)^2-3^2) for x={10,11,12,13,14,15,16,17,18}
Yeah
thank you for your help
im going to put this formula in my calculator now
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. uh?
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I have spent so long on this
Let h = initial hour hand in hours
Let m = initial minute hand in minutes
then $h_\text{final} = h + \Delta h$
UCYT5040
and $m_\text{final} = m + \Delta m$
also, $\frac{h_\text{final}}{12} = \frac{m}{60}$
UCYT5040
and $\frac{m_\text{final}}{60}=\frac{h}{12}$
UCYT5040
i also notice that $\frac{\Delta m}{60} + \frac{\Delta h}{12} = 1$
UCYT5040
but i really only have 3 equations here, with a 4 variable system
what am i missing?
@scarlet trellis Has your question been resolved?
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@scarlet trellis Has your question been resolved?
wait why are there four equations
let $t$ be the number of minutes after 7:00 now and $\Delta$ be the number of minutes requested in the answer (so $\Delta<60$)
Civil Service Pigeon
Then, $$6(t+\Delta)=210+\frac{1}{2}t+360n$$
for some integer $n$ (since the minute hand travels $6$ degrees in every minute and the hour hand travels $\frac{1}{2}$ a degree per minute)
Civil Service Pigeon
you can use similar logic to get an equation for the hour hand
it should finish nicely from here
I'd be shocked if it didn't
1 sec lemme read this
ah ok i understand
but i prefer the idea that there are 60 minutes on a clock rather than there are 360 degrees
thats confusing
$t$=$\Delta$ then
UCYT5040
it is currently between 7:00 and 8:00 (or, it is currently 7:t)
the answer is requesting how many minutes past 7:00 it currently is
do you mean $t$ is the number of minutes after 7:00 after the swap takes place?
UCYT5040
degrees gives you a way to relate the changes of the minute and hour hand under a common unit though
$\Delta$ was supposed to be the number of minutes after the swap took place
Civil Service Pigeon
mb
ok
same with minute ticks tho
eh to each their own
1hr = 5 minute ticks
1 min = 1 min tick
ok im going to attempt this whole problem now
sorry i got distracted
actually attempting it now
$t$ number of minutes past 7 $\$
$\Delta$ number of minutes that have passed after the swap
UCYT5040
$\frac{7\cdot 60+t+\Delta}{720}$ represents the position of the minute hand before swap
$\frac{7+\frac{t}{60}}{12}$ pos of hour hand before swap
$\frac{7 \cdot 60 + t}{720}$ pos of min hand after swap
UCYT5040
$\frac{7+\frac{t+\Delta}{60}}{12}$ pos of hour hand after swap
UCYT5040
$\frac{7\cdot 60+t+\Delta}{720} = \frac{7+\frac{t+\Delta}{60}}{12} \ \frac{7+\frac{t}{60}}{12} = \frac{7 \cdot 60 + t}{720}$
UCYT5040
angles are equal modulo full turns
thank you for your help, but honestly my brain is too fried today to attempt this further
i think i know what you mean though. ill try again tomorrow
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@fast heron Has your question been resolved?
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I have perhaps a very elementary question. Let $|\cdot|$ be the Euclidean norm in $\mathbb{R}^d$ and $q$ a fixed point, $x,y$ two other arbitrary points. If $|x-q|\neq |y-q|$, is it true that $y\neq x$?
psie
you can see it by the contrapositive of this statement i think
if y=x, then |x-q|=|y-q| which is obviously true
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x = y+3
yep
another way you can do this is to solve for y
so from x = y + 3, simplify this to get y = (...)
remember coordinates are (x, y)
not (y, x)
also, (-2, 0) isnt correct
-2 isnt 0 + 3
yes, that would for example be a point
if you keep putting in x and y, you can plot the graph out
another way you can do this is to solve for y
so from x = y + 3, simplify this to get y = (...)
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So im just doing some exercises in my school book: Derive a formula that can be used to calculate the volume of a sphere from its diameter.
I lowkey dont know how to proceed/ where to even begin
Are you supposed to use calculus
i think maybe it just wants you to convert the volume of a sphere formula from using the radius to the diameter
so to start, do you know what the formula is for the volume of a sphere with radius r ?
4/3 x pi x r^3 right?
Not really
Its kind of a weird exercise
The ones before was just calculating the volume
Now im supposed to think of a formula
this is not to do with this specific question
there is a formula relating radius r and diameter d
Well yea radius is the half of a diameter
1/2 d = r?
no, substitute this formula into the other one
So uhh d = 1/2 x pi x r^3?
So V = 4/3 x pi x 1/2d^3
almost, we cant forget brackets
Yea
then replace each of those with 1/2 d
No like i know the purpose
Wdym
as in just go along with it
So just do what u Said earlier
yes
1/2d x 1/2d x 1/2d
and what does that simplify to
Which is (1/2d)^3
So what would i have to do to simplify it
its easier to simplify from here
forget about any brackets for now, we're just looking at 1/2 d x 1/2 d x 1/2 d
if i said simplify 1/2 x 1/2 x 1/2 what would the answer be
1/8
if i said simplify d x d x d what would that be
d^3
ok so what should 1/2 d x 1/2 d x 1/2 d simplify to
So its not 1/2 but (1/8d) ^3
not quite
because (1/8 d)^3 would be 1/8 d x 1/8 d x 1/8 d
which i think you can agree is clearly different
Yea
1/2d^3
still not quite
think back to this
1/8d?
no bc now youre missing this
yes
So just without the brackets
because (a b)^n = a^n b^n
So what do I put in my formula
So is my formula V = 4/3 x pi x 1/8d^3
yes perfect
Fuck that was hard to think of
then that can simplify just a bit more
To?
we have a 4 in the numerator and an 8 in the denominator
Nvm 1/2
V = 4/3 x pi x 1/2d^3
you kept the 4
In the 4/3?
$\frac{4}{3} \cdot \pi \cdot \frac{1}{8} d^3 = \frac{1}{3} \cdot pi \cdot \frac{4}{8} d^3 = \frac{1}{3} \cdot \pi \cdot \frac{1}{2} d^3$
Acman
does that make sense ?
i just moved some stuff around
maybe it would be easier to see if we got rid of some stuff that isnt changing
$\frac{4}{3} \cdot \frac{1}{8} = \frac{1}{3} \cdot \frac{4}{8} = \frac{1}{3} \cdot \frac{1}{2}$
Acman
I mean I got the formula now
well it still needs to be simplified
Why is there always something to simplify
well not always, we're almost there now
Dont tell me that i gotta take the 3rd square root now
Does that even count as simplify
we dont need to do that
were just doing arithmetic at the moment
multiplying these fractions
Maybe multiply again to 1/6d^3?
bingo !
So its V = 1/6d^3 x pi
yep
Gotta take it down step by step now
Thank you for the help
Atleast you didnt give me the answer right away
Made me use my brain instead
yes no problem, happy to help
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I needed help proving M, K, N all lies on a straight line.
Question: Given $\triangle ABC$ has heights of $BD$ and $CE$ intersects at $H$. The angle bisector of $\angle ABH$ and $\angle ACH$ intersects at $K$. Let $M$ be the midpoint of $AH$ and $N$ be the midpoint of $BC$. Prove that $M$, $K$, $N$ all lies on a straight line.
1 divided by 0 equals Infinity
do you know determinants?
?
im doing normal geometry here, not coordinates-related
yea but you can still assign their x and y coords
i don't think that im allowed to do that here
Why? is that not part of your syllabus?
tho you may be right, it might not be possible to assign them exact coords
yeah i know, im supposed to do it like, not related to coordinates and descartes plane and stuffs
you should be able to assign them some variable coords tho
i mean, my curriculum didn't learn about coordinates in geoemtry yet
ah
then nevermind
<@&286206848099549185>
btw 1 divided by 0 does not equal infinity
get out
idc
wow I suck at geometry without numbers
same
@proper nova Has your question been resolved?
@proper nova Has your question been resolved?
if i wanted to prove BKC = 90, then i have to prove KN = BN = NC?
bro we have all the angles
since we can calculate BKC, we have all that
from which we can calculate KNB
do a lil angle chasing
alr
interesting that forms a circle then
let me try something:
EBH = DCH (there are many reasons to say that)
since BK and CK are angle bisectors of these 2 angles then KBH = KCH
ok from what ive got alr: -||prove K lies on (BEDC)||
-||K is the midpoint of some arc||
-||K lies on perp bisector of some segment, and so is N||
then something something nine point circle?
didn't hear the term midpoint of an arc before
i mean if you have that, we know that MN passes through the midpoint of ED
(both perpendicular)
so we're done
but how did you get that
which part
midpoint of arc
BK is angle bisector of BED
lmao
wait how did you get this
just use this to finish
only thing is that im trying to see why BKC = 90
i did some funky and finnicky stuff with the nine point circle trying to prove this
both are centres of circles, and ED is a common chord, so if the midpoint is L, ML is perpendicular, NL is perpendicular, so MNL is collinear
what the 💀 is even the midpoint of an arc
EK = KD
ohhhhh
my brain hurts when i encounter geometry 😭
i was thinking of constructing (AEHD) but i didnt realize M was the center of it 
yeah lol no matter how much i try i still suck at it
NE = ND is easy to prove since BC is the diameter of (BEDC)
the hard part is ME = MD and KE = KD
like did you not understand or are you remarking
im just remarking
and trying to see why this is true
(AEHD) is concyclic. M is the midpoint of the diameter of it (AH), thus M is the center of (AEHD)
ME and MD are radiuses
i can't seem to see why KE = KD
i only got KE = KD left and im trying to see why that is true
thats a consequence of angle bisectors and arc bisectors (no idea which theorem states it tho)
chords that make equal angles have equal length
can you elabortate more on that
?
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✅ Original question: #help-39 message
i actually have one more question i needed help with: Given $\triangle ABC$ which is an acute triangle, three heights of that intersects at $H$. From $A$, draw tangents $AP$ and $AQ$ of the circle with diameter $BC$. Prove that $P$, $H$, $Q$ both lie on the same line
1 divided by 0 equals Infinity
in the diagram above, i let $O$ be the midpoint of $BC$
1 divided by 0 equals Infinity
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hey so, i'm just curious about a concept of math... If someone wants to chat about that
i'm new to this server and i'm trying things out
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Hi, i'm with the topic, "equations with radicals" you see, sometimes you get two diferents values for x, like "x¹=4, x²=6" but why can a solution be "fake" (in mathematical terms) when you do the comprobation? (When the result does not satisfy equality)
A solution is deemed false only when the logic building up to the result is contradicted by the answer.
because when you square both sides, you create solutions that aren't part of the original
if $a = b, a^2 = b^2$ yes
south
but $a^2 = b^2$ can also come from $a = -b$
south
Like the following example, when the squares are taken off from both sides, it doesn't guarantee that both sides must be equal.
Unless there is some conditions sit upon them.
For example, if $a, b > 0$ and $a^2 = b^2$, we can be certain about $a = b$
Erebus
(Because they both need to be > 0 and a = -b doesn't satisfy the condition)
Ohh right
Erebus
Then you can reject this case.
But like i was asking, mathematicaly talking, why can a solution be "false" if it does not satisfy the equality? How can you get to that result
do you understand how squaring both sides creates extraneous solutions?
Yes, because i they wouldn't satisfy the equality?
By equality, do you mean why a solution might be false although they fit in an equation or another thing?
I don't understand where you're confused on
Mostly, I'll give you another example.
$x^2 = 4 \implies x = \pm 2$
Erebus
Here, non of the solutions are false because there is no other restrictions on it.
$\sqrt{4x - 3} = x \implies 4x - 3 = x^2 \iff x^2 - 4x + 3 = 0 \iff (x -3)(x - 1) = 0$
Erebus
Wait bad example
there's even $\sqrt{x} = -2 \implies x = 4$
but when you check $x = 4$ by subbing in the original equation, it doesn't work ($\sqrt{4} = 2$ only)
south
so the conclusion is that there are no (real) solutions
In the above case, no square roots could be negative.
This leads to a contradiction.
So, what happens?
Well, Assuming $\sqrt{x} = -2$, then $x = 4$ (squaring both sides.)
Erebus
But $\sqrt{4} \neq -2$
Erebus
So, our previous assumption is false.
Yeah, so what's the solution then?
There is no solution.
The solution simply does not exist.
It is somewhat of a law that square roots *aren't negative.
$\sqrt{x} \ge 0$
Erebus
no worries!
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I;d like to solve this using convolusions
wai
the probability density of a sum of independent random variables is the product of the probability densities
so just a^2/x^4
thats not correct
why is this wrong ?
no worries we are all here to learn :)
$f_Y$ is nonzero on $[a, \infty)$ and $f_X(z-y)$ is nonzero on $(-\infty, z-a]$
what is z ?
flynger
the variable in terms of which I'll express the final answer
I also just realised I assume both RVs are the same
I think this implies that the integral is between [a, z -a] right
so their intersection
yeah
this is thm 10.1
yup so what would Z be in this case?
maybe that question is too trivial for you and if so Im sorry, but its important to understand
the RV?
X+Y
so I have $a≤y≤x$;
$a≤z-y≤x$?
wai
( to find the bounds of the integral?)
you can insert the functions even with the cases
I don't follow
I'm just unsure of how to do this using convolusions
(which is what I wish to use here)
okay first of all what formula do you want / need to use?
from the pictures that you presented
the last one
okay what is f(z-y) and g(y) in this case?
$\frac{a}{(z-y)^2}; \frac{a}{y^2}$
wai
From direct substitution you have
$h(z)= \int_{-\infty}^{\infty} \frac{a}{(z-y)^2} \frac{a}{y^2} dy$
flynger
the what?
\[
f(x)=
\begin{cases}
\dfrac{a}{x^{2}}, & x \ge a,\\[6pt]
0, & x < a.
\end{cases}
\]
tobi
From direct substitution you have
$h(z)= \int_{-\infty}^{\infty} f_X(z-y)f_Y(y) dy$
flynger
this is only valid in its given domain
$f_Y(y)$ is nonzero on $y \in [a, \infty)$ and $f_X(z-y)$ is nonzero on $y \in (-\infty, z-a]$
ye
flynger
oops, right
so yes from direct substition you would first get this
so thats what I meant with inserting the function even with the different cases
By this you have
$h(z)= \int_{a}^{z-a} f_X(z-y)f_Y(y) dy$
flynger
I hope you dont have to integrate that, that would not be fun (but possible)
I think my course would require me to, but we usually don't get such problems on the exam
such computational ones
use partial fraction decomposition, if you wish to evaluate the integral
sure
have you worked with probability measures?
this course doesn't do measure at all :(
It's done alongside RA1
sorry I only know how to do it with probability measures
I do have a formula in mind
the pdf of $X$ is $ \frac{4h^3}{\sqrt{\pi}} v^2 e^{-h^2v^2}$
wai
yeah that works here
(very important formula in physics btw!)
Y = X^2 = T(X)
So W(y)=√y
Z=1/2mV^2
Why does your example satisfy this assumption?
the RV increases on the domain
f(x) = x^2 is not an increasing function
yeah it would not be on whole R
but on [0,inf) it is
wai
you are missing the 1/2 * m
but otherwise your done
1/2 * m is just a constant and therefore independend so you can just mulipliy it to the density of V^2
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✅ Original question: #help-39 message
@elfin stirrup you were saying something?
I asked what Tq means but I looked it up
thank you
:)
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Hello, I am in quite the bind at the moment because I need to get to calculus undergrad levels of math.. and currently I can barely do 5th grader math. That in itself isnt that much of a problem...
The problem is that I start school 13th of January.. and I need to get up to a reasonable level by then. I dont particularly want to cram but I dont think I have any choice? Are there any good tools I can use to help me along the way? The software my school uses is ALEKS but of course its paid software so I dont wish to spend too much time with it. I spent 13 years in school yet I remember literally nothing. I am a bit stressed by now.. 
Sorry if this question is too generic..
Work from the ground up and understand the fundamentals. Don't be scared to stay on the beginner material until you fully grasp it. Once you learn a topic, push yourself with harder questions to test how strong your understanding is.
I think the main problem here is the time limitation
It's already November, and school will open on January? 
I think that skipping a few topics is a must atp
Just learn what is more important, try to watch YouTube serieses like Organic Chemistry Tutors
And watching a few 1-2 hour "intro to alg", " Algebra review", "basics of trig"
After watching those 1-2 hour videos, use apps like Khan Academy to strengthen your understanding by practice
They said they can barely do 5th grade math, so I'm gonna assume they could need to start even earlier
True
yeah and to kinda add onto this, don’t worry about going too deep into it because usually the intro calculus classes will kind of guide you through the problems so you can learn any gaps if you need
Only having 2 months to re-study 13 years of math is just... Insane
@urban crypt Has your question been resolved?
Thing is that this seems a bit scary 💀
to be honest a lot of it is just going to be repetition
They expect me to get up to that class before I start if I read that right? English isnt my first language
that means I need a score of 76% or better
I did it once already and I got 18% 😭
yeah you need to place into it
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i was trying to appraoch this question with a stars and bars method, i think i got there would be 97 choose 3 ways if we ignored the odd condition, but im not entirely sure how to appraoch it with the odd condition (maybe might have to use a different method), i was thinking maybe it involves reducing the previous 97, maybe dividing it in half or something similar, as we need odd gaps between each bar?
x_i = 2a_i+1 because they are odd
@shut flicker Has your question been resolved?
so does it become like this
The concept is right but you're overlooking one thing
can u hint where that may be
What's the least value a_i can have in your method
ah is it that i should have done 2a-1 instead, since x_1 can be 1, so if 2a_1 - 1 = x_1, then 2a-1 can equal 1, so a = 1, whereas with 2a+1, i can't get x_1 = 1 unless a is non positive
Yup
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What are some applications for the fundamental theorem on homomorphisms? And why can you say that the diagram you draw for it commutes?
Same as first isomorphism theorem correct?
this right?
Yes
Ok so just slightly different format
? That's not similar to the first isomorphism theorem, is it?
That's 1st iso
Wait lemme check my textbook
I might be tripping
This is what I have in my book, its just not labelled
yes
Ok phew
So what I mainly use it for is like elaborating on "induced" homomorphisms whenever I'm creating a proof
A lot of the time if you have these conditions satisfied then its easy to prove that \tilde{\phi} is bijective since according to this theorem its already an isomophism
There are a few examples I have
How do you remember it? Like can you describe it in one sentence intuitively or something
Well its the diagram
You just think of the diagram?
But (i) is not in the diagram, is it?
Hmm
Well I guess you can memorize that little part
Its not in my book for some reason
True
Ok and one more thing:
Do you remember all the three iso theorems?
Uh no
haha
Partly because I haven't gone in-depth and partly because my book doesn't name the theorems 🥲
Alright
I gotta go eat
Thanks
You can keep this open to see if anyone else can help you with memorization
So the new question is: How do you usually remember the three isomorphism theorems? Do you have like a one-sentence-intuition you keep in mind?
Also by the way, apparently yes, it is the first iso theorem, we just named it a little differently and that's why we don't call it that for some reason
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hey im unsure why these angles are the same
they don't have to be the same, that's just given
Ik but how would I know that the top angle is 30
Nc is perpendicular to that inclined
can you show me a diagram?
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#19
Do I have to calculate the area of both circles and subtract their intersection?
So I’m assuming the circles have radial bounds of 0 to their respective equations, and angles 0 to pi for sin and -pi/2 to pi/2 for cos
I can do that all well and dandy, what about their intersection? How can I calculate that
?
<@&286206848099549185>
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I dont really understand the answer
,rccw
a-b the whole square = a² - b² - 2ab
that should be about it yeah
don't look at it differently just because of the -x
what is the question?
But we have two specific formulas
a^2+2ab+b^2 for when (a+b)^2
And a^2-2ab+b^2 for (a-b)^2
When i asked chatgpt he said the answer is x^2+2x+1
But i get the answer in the picture
,rotate
right so the 'a' being -x, doesn't make it a + b the whole square.
you compute it just with the formula of a - b the whole square
it just gives you a funny 'a' that you don't expect to be +/positive (while doing the computation)
Ohhh so -x-1 is treated as a a+b so i have a positive 2 when multiplying
no no, -x - 1 (the whole square), is treated as a-b (the whole square).
the "a" Here being -x (negative guy) doesn't change the fact that it's gonna be a - b the whole square.
So the formula is a2-2ab-b2?
yes
and not the +/positive formula
might have gotten confused with the -x squaring to positive x²
but you should not really ask chat gpt for answers, as it has a lot of errors/mis understandings and you won't get what you're doing
there is, he means the a - b the whole square and a + b the whole square formula.
If you sub b for -b'
You get second formula
yea there's 2 formulas then, aren't they!
Say you wanna evaluate (-x-1) ^2
Think like this a=-x , b=-1
Then do (a+b)^2
If you wanna do by (a-b)^2
You can think a=-x , b=1
Or you could be smart and think (-x)^2 =x^2
I mean... do we really wanna confuse someone who's just learning this?
it's simple enough either way
Ok im genuinely confused now
Our proffesor told us to just fit in the numbers into the formula depending on the +/- beetween a and b
Yes
Is the -x treated as x ?
nope
it's treated as -x, but there's a difference between treating it as -a and +a
so when I speak about -a or +a, I'm speaking about the left side of the sign in between
let's not confuse you and take 55 + 45 here for example
when I say +a, here I mean 55 because it's left to here
but if I say -55 + 45
I take "a" as -a
get the point? it can be -a or +a depending on the sign of the variable/constant
Ohh i see
(−x−1)square2 =(−x−1)(−x−1)= xsquare 2+x+x+1=xsquare2+2x+1
now think about this, -a doesn't matter here really because you compute two numbers hmm and the second one matters more
so, what matters is the b sign
Ohh ok
now here, the b is "-1" so it has a negative sign
Ye
that means, you use the formula for (a-b) ²
Yep
the a being -x or +x, does not matter
you can even confuse it by saying the "a" as -x² or x²
but it's just gonna be "a"
the "b" matters majorly here
So in this scenario how would i fit the numbers into the formula?
now we plug in what's "a" and what's "b" here
Shouldnt it be a2-2ab+b2
yea it is, we just flipped the order
changing -2ab to the right edge doesn't matter
because we brought +b² to left without changing anything
it doesn't matter if you do it that way as well
yeah, now plug in a and b to the formula
and check what's happening
be careful with the cancelling after you do it
Im stuck at the -2 times -x times -1 since its
-2 times -x is 2x and 2x times -1 is -2x
But in the original answer it should be +2x
mhm
,rotate
now think of it like this, what would be -2 times positive/+x?
right? now what if the x was also negative? the answer changes it's symbol right?
no no dont move on yet
we have -2 times x, resulting in -x.
U mean -2-x?
no, I mean -2 × X being -2x, then what does -2 × "-" X be?
+2x
-2
so you get the 2 times a and 2 times b, now our step is to multiply those both:)
so what is -2 times 2x ?
-4x
exactly!
that's 2 times a × b, don't get confused if "a" is something hard or weird!
and lemme just point out the idea here, you multiply 2 times "a" properly, and 2 times "b" properly.
before you can multiply those both together
Omg i know the problem
I was solving this thinking x2+2x+1
Is the answer what i got from Ai and photomath
they may be correct
but they most likely mis understood your wording
mmmmm it would be if something was different, but I told you wrong somewhere, where is it?
are we still on the (a+b)^2 / (a-b)^2 thing?
(Hint: I did no calculating error, something went wrong in calculating the 2ab)
Idk im genuinly confused
Since i done all my other with 2 times a times b rather than 2 times a and 2 times b
scrape out everything, think of -2ab when a is -x and b is -1
Are we still stuck on this?
Ye
okay, recap, cause the explanation is pretty easy
we're not stuck really I'm just trying to get him though it so that he understands it completely
You have to know the following properties of arithmetics and thats kinda it:
$$a\cdot (b+c) = ab+ac$$
$$(ab)^c = a^cb^c$$
Uhh i dont think so
I may have but i wasnt a real math person trough 5-7 grade
Now i want to lock in
Okay, to ease out your confusion. For this time I'm telling you where I went wrong,
when I tried to calculate 2ab , I thought it was 2(a) × 2(b). Something that is only correct if it was 2 (ab) [ with ab in bracket]
it's a common error, and you only had to be multiplying it once
Ohh so its 2 times a and the answer of that is ans times b
yes exactly
thinking you should multiply 2 times a and 2 times b, then multiply it again, is a common error
Oh ok
Okay, well, lets recap on how distributive property works:
Do you agree that something like:
$3 \cdot (5+2) = 3 \cdot 7$
What is original que?
?
this is just pemdas applied
now let's not get too complicated of ourselves^ and see what 2 times -x is, and then the answer of that to times -1.
So 2 × -X × -1
Yes
Guys its hard keeping up with two people
mate appreciate you, but this is in a complex language for him right now
need to help him with pure basics, nothing else
@edgy laurel think of this
and tell me the answer what you think is correct. (Nothing too complex, just ease out your mind)
2️⃣ ✖️ ➖ ❌ ✖️ ➖ 1️⃣
Red X is x as in x mass, and black x is multiplication sign
My original answer
correct!
One mistake
Oh
So my problem was checking with AI
Where
When you write b take as +1
But isnt it -1 since u need to take the - if its infront of a number?
-2(-x)(+1)
Could u explain why +1?
Yes but here we applying (a-b)^2
a-> -x
b-> +1
-x - (+1)
= -x-1
Problem is i dont understand why -1 would turn into +1
If so
Then AI was indeed correct
Might i try to take a jab at it? I think distribution is easy enough of a concept.
Go on
If +1 then answer
x^2+2x+1
sure
A bit off
Using pemdas, we got this results previously, which, mind you, is also = 21.
Well, distribution basically tells you that the order of operation doesnt really matter
So, you can multiply and then add
or add and then multiply.
going back a step
$$3 \cdot (5+2) = 3 \cdot 7$$
but also:
$$3 \cdot (5+2) = 3\cdot 5 + 3\cdot 2$$
Ohh i know about that
We learned distribution + commutitation or commutation
You can multiply term-by-term
You can check on your own, both expressions are equal to 21.
Oh i understand that part
Without too much on the details of why
we say that multiplication distributes over addition (what we just did)
And that exponents distribute over multiplication
Yes
mmmm I see, the -1 does not turn into +1 .
-1 is actually - times +1 , which turns it into a -1 ( - times + is -) .
We just take it as +1 and leave the minus symbol left of it because the formula we're using, already has in the account of it being ("a" '-' "b")².
Suppose, it was actually -x + 1 instead of -1 ,
We would use the other formula wouldn't we? so when we consider the b, we take it as + and not negative. But when we think of a, we take it as whatever it is no matter what it is. Because the formula only changes because of it being - or + , and the formula has taken into the account of the number/variable without it being positive or negative.
Well, we can use these to easily solve for why we get x^2 + 2x + 1
OMG ik
Bc of the minus in the formula we remove the - from the 1 since its alr in the formula by default
yeah
Consider a small fact: We usually call "factorization" to the process of doing """inverse""" distribution
sooo, as you just said
$$(-x-1)^2$$
$$\left((-1)(x+1)\right)^2$$
$$(-1)^2(x+1)^2$$
$$1\cdot (x+1)^2$$
$$(x+1)^2$$
took a bit too long to tell that, but I hope you've learnt common errors and mistakes along the way.
the level you're in, it does not matter in a bad way for you to do mistakes.
Learn from your inability of knowledge. The lesser things you know, the more you can learn and you aren't compulsioned to be perfect. So don't take it too hard, and be in a stage where you can sleep a good night even if you hadnt studied for the exam in the morning
I think i understand other stuff
Dont mind the questions in croatina
I will hit yall up if i need sum more help
U can make this channel available now
Yeah 👍 glad to be of help
you actually need to do it by typing ".close"

