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if they were in the same plane they would never intersect
well
I think they are technically skew
but if they were in the same plane they would be parallel
but since they are not in the same plane they are skew
sorry to backtrack there
In three-dimensional geometry, skew lines are two lines that do not intersect and are not parallel
https://en.wikipedia.org/wiki/Skew_lines
they are parallel (and not skew)?
I presume the drawing is a cube
the distance between A and G is the same as the distance between B and H
parallel is for lines in the same plane
Yeah thats what I was confused about
^
it was sufficient i was in a call im so sorry
ABGH generates a plane
yeah
hahah
i think the official definition is that same direction vector = parallel
and the lines definitely have the same direction vector
thanks guys!
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Hi can anyone help me?
x=2*55 right?
ADCB its a quadrilateral inscribed in the circle hence y+55 =180 right?
yeah
angles at a center
but do you know the proof?
isn't the proof just angles at a circle
or am I wrong g
what says the theorem "angles at a circle"?
what does it say?
... i say that x=2*55 because i used this theorem
ohh
do you know the proof of that theorem ?
yes
what about the reason
so it's the same theorm just different positions?
yes for the 2 question
for the first its just the sum of anlges of trianle ...and angle between the ray and the tangent its 90
angles subtended at the centre of the circle is double the angle at the circumference
i think thats how they write it in gcse
and for this wuestion it would be related to tangents right?
Angel C would be 90 degrees
or am I wrong
Good nihft
I'll try to solve the rest of it alone
I don't think i can but yeah
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where did the cos^2 go?
compound angle identity was applied
which is?
$\cos (2 x)=2 \cos ^2 x-1$
heavy
also dodgy notation on that page
how so?
improper () to clearly indicate arguments of the cos
I dont mid the first two as much
but the
cos2(6x)
is horrid
yeah It's a screenshot from a yt video
in my humble opinion
the only time writing cos/sin without brackets is acceptable
is when its just x
so cosx or sinx
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What makes x positive?
All good
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yo
11?
@vapid steppe Has your question been resolved?
i did (16+6)/2
should be right
@vapid steppe Has your question been resolved?
how do i finish the equation
you're already 99% of the way there
what goes after x in there
after y was the major axis length, which you found
so after x is what
4?
how can y be the major axis if itβs 25 while the minor axis is 64
oh my bad, i was being dumb
the denominator is the square of the minor and major axes
the stuff after y was the center of the ellipse
so 11 was the y coordinate of the center
and yes
4 is the x coordinate of the center
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Hello! I am playing a game and looking for the most mathematically efficient/fastest way to solve the puzzle.
There are a few rules and some information to help:
- This game has 6 players, split in to two teams of 3 players, those teams are divided between the blue and brown colors on the map. Any player can cross between the two halves of the map any number of times (ideally the fewest times possible).
- The two teams of 3 players will both start at their respective number 1 on each half of the map.
- The numbers must be 'activated' in order to complete the puzzle.
- In order to activate a number, you must first stand at n-2 of the current number you are trying to activate to receive a buff that will allow you to activate a number.**
Any number of players may stand at a number at one time to recieve this buff. i.e: all three players will stand at number 1 to receive this buff. - **The numbers may only be 'activated' by a player if you are at n-2 of the current number you are trying to activate. This rule only applies to number 4 and beyond. Prior to number 4, the buff you need to activate a number will always be at number 1. i.e: a player could not skip to number 5 and wait for 4 to be done without first standing at number 3 to recieve the buff necessary to activate the number.
- Any player can activate any of the numbers respective to their colour, so long as they are done in order.
- The goal is to activate all six numbers in order in the fewest moves possible, as fast as you can.
If you'd like to try and help, try just doing the blue side only first! Remember each side only has 3 players, and a number cannot activated without first standing at
n-2 of the number you are trying to activate.
Thank you :D
@potent hare Has your question been resolved?
For some more information, the way we solve it right now is very inefficient. Only 1 person out of each team will oversee activating the numbers, in an order that goes like this: 1->2->1->3->1->4->3->5->4->6.
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@potent hare Has your question been resolved?
Try #discrete-math
so what stops you from doing this
or it's like, someone else must be at nβ2 in the present, not just you in the past
masmis
Hello,I need help in my assignment and the submission is after tomorrow, I searched on google but idk if I can trust it cuz its different from the example its central limit theorem,z score btw here is the question
In a study of the life expectancy of 400 people in a certain geographic region, the mean age at death was 70 years, and the standard deviation was 5.1 years.. If a sample of 50 people from this region is selected, what in the probability that the mean life expectancy will be less than 68 years!
I'm having hardtime in labeling and idk what to do with "less than 68 years".
Should I ignore the 400 people? Cuz in google they did ignore it
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.reopen
How does this have a solution?
!show
Show your work, and if possible, explain where you are stuck.
π
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Wtf
does that say n! * 2n! in the denominator? and n^3 * 2n! in the numerator?
yes to both
and + (2n-1)*n!
Ok, thanks
np, but i've been stuck on this problem for the last 15 minutes
i'm just dying
@near crag Has your question been resolved?
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i got to:
$ae + \frac{b}{e} + c = \sum_{n=0}^{\infty}\frac{n^3}{2n!} \quad + \quad \sum_{n=0}^{\infty}\frac{1}{(n-1)!} \quad - \quad \frac{1}{2}e$
hannibal
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Not getting much progress with this question
just to make sure, you need to prove IVT applies first right?
Yes
so I have that x must be > 0
Im sure im doing something wrong trying to figure out IVT
Determine whether the function is continuous on its domain
but basically I thought that if a function has a point below and above 0 and is continous
a solution exists
but for this case there is none below 0
Umbraleviathan
There are values of x such that x > 0 such that s(x) < 0
Oh right
s(x)
I guess what im having trouble with then is finding the values
because I cant solve for s(x) = 0
No
But you can prove that s(x) is continuous for all x > 0
And then you can prove that there exists a value of x such that s(x) < 0 and there exists another such that s(x) > 0
Then you need to prove that s'(x) is continuous for all x > 0
so to get those two points id kinda have to guess and check in a way?
right
MVT
But to get those two points where s(x) is < and > 0
is it kinda like guess and check
I mean let's be real
Let x = 0.001
That's definitely gonna be below 0
And then let x = 10000000000000000
That's definitely gonna be above 0 lol
And then you just need to show that s'(x) is either monotonically decreasing or increasing
just to make sure, I have to make sure s'(x) is dec/inc or s(x) is dec/inc?
I have to study more on MVT
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can someone help me get the answer to part b? my brain isnt braining
i know that the answer to part a is 156cm
Do you know what integers are
Well whole numbers and integers are different sets but sure
And I'm assuming they want a nondegenerate rectangle so the side lengths will end up being natural numbers
You know that to get the perimeter you need to add up 4 numbers, 2 of which are the same and 2 are also same
yep
in this case would it be 3
3 is not the lowest natural number
it cant be 1 can it
Oh wait I'm dumb
so 2?
I didn't read the text above it
oh
Send it in 15
ππ»
Well hm now I'm thinking
Because I didn't read the excerpt at the top
Do you know calculus optimization?
i dont
how did you get 1/2 e?
bro?
Ffs
1/2n! =/= 1/2*n!
Maybe list out different combinations of integers that multiply to 1521
wouldnt that take ages
Uh
Maybe
Not really
,w all integer factors of 1521
Oh apparently 9 and 169 are the only integers LOL
Well
No
oh lol
oh
Hopefully I didn't do a dumb
it doesn't?
is 17+17+13+13?
Alright I got every one
It shouldn't
Did I do a dumb again
Oh my god
I'm failing as a helper lol
Let me
Yeah this
I meant 117 I guess lol
oh lol
and it cant be 39x39
since that would be a square
the 13x117 combination is 260 if im not mistaken
which should be the answer
bro
lol
I'm sure you can read, can you?
I'm sure your ability to navigate is not reduced down to red arrows and not making connections
Oh sorry
It should
ill try 260 as an answer for b
Because 39(5) = 156
39(4)*
Equals 156
Iirc the theorem is that the square has the smallest perimeter given area
I'll have to check
lets go i got it
great
but i had that answer b4 and it said it was wrong lol
weird
thats why i came here
They did not explain well cuz the tutorial said claim help 0
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β
Let $A$ be a fixed area for some quadrilateral. The area and perimeter of this quadrilateral can be expressed as:
$$A = xy$$
$$P(x,y) = 2x + 2y$$
Since $A = xy \implies y = \frac A x$, we can rewrite $P(x,y):$
$$P(x) = 2x + \frac{2A}x$$
Taking the derivative and optimizing:
$$\begin{align*}
P'(x) &= 2 - \frac{2A}{x^2} &= 0 \
&\implies x &= \sqrt{A} \
&\implies y &= \sqrt{A}
\end{align*}$$
Therefore, the quadrilateral of area $A$ that minimizes perimeter is a square of side lengths $\sqrt{A}$
Umbraleviathan
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Alright so I ain't tripping balls lol
@prime vessel if you don't know derivatives, it's fine, derivatives are basically slope of a function.
But yeah I can confirm the 39x39 square
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hi
I have a question ..
y=(1/x)^x , find its second derivative at x=e and then find e^e (y")
I've tried it many times, it becomes messy and everytime i do it , i get a different answer , i dont know what the right answer is
Show ur work
And for all times i tried i got a different answer
Am i just dumb
Just were am i going wrong??
,w d/dx(d/dx(x^(-x)))
I tried using the partial derivate for the first order derivative then differentiated it again to get the second derivative
And then i put x=e and multiplied by e^e
<@&286206848099549185>
By substituting x=e in the equation given by wolfram alpha and then multiplying by e^e gives me 4-1/e , is it right
yes?
I dont know im confused
Wait give me a sec let me write it down neatly
k\
its alright
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Hello, can someone help me understand some questions on exponents im struggling with
how do i write math with a keyboard
use bot
you can sen a picture?
let me send a pic wait one sec
actually the question is (3squared+4squared+10squared) to the power of 1/3
does that make sense
that
9+16+100=125 the cube root is 5
yep
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i think its c because the det b is 0
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I need help understanding the question
pls bruh
@past hornet
@lost relic
@marsh rapids
don't ping random people
@neon sierra Has your question been resolved?
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i have not taken matrix algebra yet but i need to solve something like this by hand
i understand how the multiplication part works, but how do i account for the 36 and 0? how do i compute all of this?
if you multiply that matrix by that column vector
it will be the case that you get the top row
with its first entry times v1
plus its second entry times v2
will be equal to 36
and the bottom row with its first entry times v1
plus its second entry times v2
will be equal to 0
alright
this is just an ordinary system of equations
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I'm trying to get values of a and b, while solving I'm getting b =0, which seems wrong.
Fyi your C is wrong
That is probably why your A and B are wrong
yeah it is 1/2
Yeah C = 1/2
Because you used C = 1 here, it lead to A = 3/8 and B = 0, but if you used C = 1/2, you'll get different values
I'm solving again. Many thanks π
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Can someone help me understand how they simplified this:
Well, everything is square rooted (they have the same exponent), so you can multiply the two arguments
so you can take (4-x^2) and multiply it w/ what is inside the other root
and then take the square root of all of htat
from there, it's simple algebra
distributive property and simplifying
it's like β(2) * β(3) = β(6)
Yes, but I'm not sure how that works..we'd get sqrt((4-x^2)(x^2/4-x^2)+1)..
yep
so you would distribute the (4-x^2) to ((x^2/4-x^2) +1) using the distributive property
resulting in
sqrt(x^2+(4-x^2))
simplifying results in sqrt(4) = 2
How did that work? How did the distributive process worked here..sorry, this all looks visually confusing.
ok hold up
FOIL it out
u wouldn't need to
Or do a substitution, and let a = 4-x^2
And then you have a * ((x^2/4-x^2) +1)
When you multiply it, you get (a * (x^2/4-x^2) + a * 1)
Plug back in a
a u substitution?
Just a substitution in general
How does the distributive process work here, the one o7 recommended..
that seems easier..I just don't understand how it works on these terms..
$(4-x^2) * \frac{x^2}{4-x^2} + (4-x^2) * 1$
dldh06
It's literally what I showed
.
Sorry..makes alot of sense. I'm just shit at math. Thanks for putting up with me..
@high wolf Has your question been resolved?
Sonny I've helped you before, you aren't shit at math. we all get stuck sometimes
keep it up
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where did the (7n)(7n+1) come from
original
in $a_n$, the numerator is $7\cdot 14\cdot 21\cdot...\cdot 7(n-1) \cdot (7n)$ so the numerator of $a_{n+1}$ is $$7\cdot 14\cdot 21\cdot...\cdot 7(n) \cdot (7n+7)$
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thats not the numeratore
i extended it back one bit
you would have that 7(n-1) before the 7(n)
which is why when you replace n with n+1, you get 7n(7n+7)
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Help
I wanna start studying
what do you need help with
take practice tests
review questions you have no idea how to do and also the ones you take a guess on
But how tho
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Let $F = \mathbb{Z}_2[x] /(x^2 + x + \bar{1})$. How many elements does F have?
perhaps the top should be Z_2[x]?
yes sry
OOKK
F should be the polynomials with degrees less than two right?
Is this right? $F = {x+1, x, 1} \implies |F| = 3$
OOKK
what about the identity class?
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Ok so I have that since f(x)>epsilon we know that the set will contain the x's that result in f(x)=1/n, or that we will have a subset of the rationals
And then by the archimedean property, if you give me some eps>0 I will be able to produce a 1/n that is smaller than that epsilon
so we can only use rationals with n<c where c is some real number
Is that enough to say that this is a finite set?
Please ping me if you respond I am cooking right now
@summer trail Has your question been resolved?
<@&286206848099549185>
@summer trail Has your question been resolved?
@summer trail Has your question been resolved?
@summer trail Has your question been resolved?
I guess so, we all can guess the idea. I would just say for some c>0, f(x)>=c.
Let n be the largest integer such that 1/n >= c, then for some natural k with n>=k, we have f(x) >=c for x being a rational with denominator k. Let Sk denote the set of rationals in [0,1] with denominator k, (lowest terms) , notice Sk is finite as you have only finite amount of naturals m, such that m/k =< 1. Then you notice the set that you want is just the union of Sk for 1=<k=<n, which is certainly finite.
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women β
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is sample variance just defined as this
is there anything special about it because my material only talks about it twice and only briefly mentions that it changes with sample (same as sample mean) and that it's not normally distributed
i understand that a rv can be normally distributed but i dont get why my slides say the sample mean is normally distributed but the sample variance is not
As far as I understand it, you can use the sample variance to calculate the variance of the distribution of the mean
although I may be mistaken and it would me the population variance
let me check rq

so the sample variance is talking about what the sample mean can take on?
are the xs normally distributed
because i also understand that the sample mean itself is a random variable as well
we assume so
it is
yea
heres what I was talking about, its known at the central limit theorem: https://en.wikipedia.org/wiki/Central_limit_theorem
In probability theory, the central limit theorem (CLT) establishes that, in many situations, for identically distributed independent samples, the standardized sample mean tends towards the standard normal distribution even if the original variables themselves are not normally distributed.
The theorem is a key concept in probability theory becau...
i swear i hate CLT everyone just says CLT something something it works
well
if the sample is normally distributed
then any sum of them is also normally distributed
yep
lmao its a very powerful tool in statistics
anyway im guessing the sum/difference of 2 independent RV is also normally distributed
it's a fundamental property of normal distributions
i'll assume it to be true for now
iirc the sample variance is chi^2 distributed
i dont take stat2372 but i go to the lectures in hopes of learning more
anyhow not the point
i dont get why my slides say the sample mean is normally distributed but the sample variance is not
what tells me the sample mean is normally distributed but the sample variance is not
well the sample follows a certain distribution
well i suppose if the sum is normally distributed then so is the sample mean that makes sense, kinda
like
i just dont understand what makes the sample variance not normally distributed
is sample variance also a RV?
oh
so like
they should say that
yep
(if they are iid which they are)
you wouldn't expect something like X1^2 to be normal
why not
well just think about the values
a normal RV is symmetrically distributed on the real line
when you square it
you definitely lose all the symmetry
half the real line is no longer realisable
because smaller numbers get squared less?
like
if you have a discrete RV
say binomial
and you square it
you destroy the original distribution
so like if 6 7 8 is symmetric, 36, 49, 64 is further stretched on the 49 - 64 compared to 36-49?
the square of a binomial RV is no longer binomial
so adding, subtracting, multiplying, dividing all fine
all gives you back a normally distributed RV
but once u square it it stops being normally distributed?
by constants
right constants
but not by other RVs
yeah so if i do X1 + Y1 that's fine
in fact like
if i do X1 * Y1 that's not fine
oh what
distributions are very specific
but are we not saying all of these are "approximately" normally distributed?
the sample mean of an iid sample will be approximately normally distributed
but that's a consequence of CLT
right
even then it's not always true if you don't have the right conditions
and sample variance is not approximately normally distributed....
because CLT doesn't apply?
it's not in the same form
in what form
well idk the slides seem to also say that even if it's a little bit dependent it still works
honestly this week has been quite a jumbled mess i dont really understand why CLT applies in some cases and not others
so it is actually the sum of independent squared normals
and what exactly clt is doing to make things approximately normally distributed
it might be out of the scope of what you're doing
π¦
usually i've seen CLT proven using characteristic functions
hard to wrap my head around concepts that they just go: haha too hard to prove just memorise it hope u understand
i tried looking on youtube but they lost me on taylor series
i better learn how to do that it seems extremely useful
it takes a bit of theory to develop
ok so reading wikipedia, chi^2 is just some special gamma distribution
i've seen gamma distribution before
since Xis are normal
oh normal rv
and you square them and sum them in the sample variance
right
so it's chi^2
so doing Xi-Xbar is still normally distributed
but when you square it it becomes chi^2 distributed
i'll write that down as fact for now i suppose
but intuition wise that's fine
otherwise it's a bit too hard to remember or convince myself
aight thanks snow
.close
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q3a
what can you add to both sides to complete the square
what does Q2 look like
(x+2)Β²-5?
oh hold on
that's correct, ish, you've turned an equation into an expression somehow
so we're solving the equation for q3?
yyup
but it says complete the square tho
do i continue with this?
you've just turned something that looks like 2x = 4
into 2x
the equal sign just disappeared into thin air
(you should not do that)
(x+2)Β²-5=0 is correct
sorry, (x+2)Β²-5=0
x=sqrt5+2?
ok we start here
(x+2)Β²-5=0
add 5 to both sides
(x+2)Β² = 5
what's the next step
x+2=sqrt5?
3
is that the only answer for x
-3
so what should this be instead?
btw why does sqrt always have + and - tho
because, when you square root something
you dont know if it originally was positive or negative
it could be either
x+2=+-sqrt5?
so x=Β±sqrt5 -2
fantastic
also this only applies if the thing you're looking at is already squared
so let's take x = 5
βx β Β±β5
it's ONLY if it's taken to an even power that we do the Β± thing
oh ok
so x^4 = 16, x^2 = Β±4, x = Β± 2
btw is it necessary to put it in order like -2Β±sqrt5?
no
BUT
i would say use brackets
if u wanna put the -2 at the end you want to write +-sqrt(5) - 2
just to make sure everyone knows the -2 is not inside the sqrt
to make it as unambiguous as possible
if i was writing on paper i would add the hook at the end of the hat of the sqrt
to show that's the end of the sqrt, everything after this hook is NOT inside the sqrt
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Bro
d
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@fading citrus
Yeah thatβs good
You need to be more descriptive with the math question
Like what are the degrees on the angles
Sorry I meant the illustration..
You need to fill out the rest of it bro
Youβre missing half of the angles
Closed by @young wraith
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Very confused about how to solve functions and finding range.
all range is, it's the solution you get from putting the values of x in
The range of S under f would be the set of outputs that the elements in S have
I.e., simply plug in x = -1, x = 0 and x = 1 and put what you get together in a set
Closed by @rose sequoia
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is there a formula to be used on the 1st problem?
charge formula
?
sorry i mean coulomb's law
@sage epoch Has your question been resolved?
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hello
hii
id no idea
about
maths and i ddint get .
good marks in maths
what i should do
??
Or ask more help from her
Because maths isnt that hard its mostly formulas
Where you are having more problems
What lessons
in circle
Geometry you mean
You should watch videos in youtube
What grade are you in if i may ask
k
Ok
wjat is c1
grade
Which year are you in?
grades are numbers not letters
15
Grade 15?
So you are in grade 9 right? 9th school year
congrats
and..u
me?
good
ok
not so weak
good
k
Patterns more so
Have you done multivariable and vector calculus
It's patterns and bullshittery
But now im learning calculus limits
English is not my first language so i thought "formulas" was the right term to use
@upbeat moth Has your question been resolved?
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Wait why does this not hold? What rule am I breaking?
Please don't occupy multiple help channels.
1/(a+b) != 1/a + 1/b
it is easy
correct but neither side is equal to 1/(a+b)
minus is turn into 1/
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!15m
Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.

hey
@alpine sable Has your question been resolved?
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Hey
I need help with exponential equation
When i do logarythms here
i just get into a loop
and i can never solve it
and i cant make the bases the same
Consider rewriting 3^(x + 1) as 3 * 3^x and factor 3^x out of the left hand side
3^x+3*3^x=4
Right, now add the similar terms
Could you maybe write it out? i cant follow at all
i know the solution is 0
just out of looking at it
but the way to get to it is fcked up
$1 + 3 = 4 \$
So
$3^x + 3\cdot3^x = 4\cdot3^x$
A Lonely Bean
Thus you have $4\cdot3^x = 4$ or $3^x = 1$
A Lonely Bean
man i love u
What?
still dont get it
getting it explained by a friend rn too still not understanding it π
just lovesir bean
How I am understanding it (feel free to correct me if I am mistaken):
3^x + 3 * 3^x can be also written as: 3^x + 3 * 3^x * 1. The one does not impact the value of 3^x.
Since 3^x appears twice, you isolate that out so it becomes: 3^x(1+3)
Which then becomes 3^x * 4, or 4 * 3^x
@fluid hornet Has your question been resolved?
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Show that (n^2)a^n converges to zero for 0<a<1
Closed by @spark isle
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I have been trying to solve this forever.

