#help-0
1 messages Β· Page 578 of 1
- check if the {(1, 0, 0), (2, 1, 0), (0, 0, 3)} make a basis for R3 or not
- write down a linear combination of them
- compute T(x, y, z) on the linear combination
<@&286206848099549185> could you please answer me? I really need this
All of them I believe
no its 0.5
just move on
whatβs the solutions of sin(x)=-1/2 if x is in [0;2pi]
@keen python
You can simply get your standard matrix by $\begin{pmatrix} 1 & 3 & 3 \ 0 & 2 & -3 \end{pmatrix} \begin{pmatrix} 1 & 2 & 0 \ 0 & 1 & 0 \ 0 & 0 & 3 \end{pmatrix}^{-1}$
zslya
God bless you mate, much appreciated.
No problem
Does the same go for a quadrilateral thatβs inscribed in a circle with the perpendicular medians?
@muted raft I'm not sure what you are doing
is there another way
Order my "Ultimate Formula Sheet" https://amzn.to/2ZDeifD
Hire me for private lessons https://wyzant.com/tutors/jjthetutor
Read "The 7 Habits of Successful STEM Majors" https://amzn.to/2FFJlR2
in this video he said that
A is equal to [ T(e_1), ...., T(e_n) ]
Well, you can always express the standard basis in terms of $\begin{pmatrix} 1 \ 0 \ 0 \end{pmatrix}, \begin{pmatrix} 2 \ 1 \ 0 \end{pmatrix}, \begin{pmatrix} 0 \ 0 \ 3 \end{pmatrix}$ and then just compute $T\qty(\begin{pmatrix} 1 \ 0 \ 0 \end{pmatrix}), T\qty(\begin{pmatrix} 0 \ 1 \ 0 \end{pmatrix}), T\qty(\begin{pmatrix} 0 \ 0 \ 1 \end{pmatrix})$
zslya
but how do I compute it if I dont have T yet
@keen python Ok, lets make it simple and do it the easy way
We will apply the definition of linearity to find the standard matrx.
Do you recall what that means?
Shouldn't linearity be the first thing to learn in linear algebra 
Standard matrix is just columns that are images of the standard basis. So just T(1, 0, 0) T(0, 1, 0) T(0, 0, 1)
So we want to find this standard matrix. We already know from our given that T(1, 0, 0) = (1, 0)
So our first column would be (1, 0)
Now, our second vector from standard basis we need is (0, 1, 0)
We need to write (0, 1, 0) as a linear combination of vectors from your basis.
which was why another person had asked you to check if they form basis in R^3 or not.
So we need to observe that $\begin{pmatrix} 0 \ 1 \ 0 \end{pmatrix} = \begin{pmatrix} 2 \ 1 \ 0 \end{pmatrix} - 2 \cdot \begin{pmatrix} 1 \ 0 \ 0 \end{pmatrix}$
zslya
so before you do anything check if we form a basis ?
ok Can you continue from here then?
you want to transorm it to canon basis
Since we already know that they form basis, that means every vector can be written as linear combination from those vectors.
and the results form the standard matrix
I see why it works but somehow I dont understand why
What part do you not understand?
do you maybe know any good tutorials
@muted raft like why do we have to do this whole stuff ?
to express the mappings ins canon basis
cant we just say that standard matrix is (1,0), (3,2), (3,-3)
No.
Your basis is B = {(1, 0, 0), (2, 1, 0), (0, 0, 3)}. The matrix you wrote is the matrix associated with basis B.
You want to change it to standard matrix which is associated with the basis S= {(1, 0, 0), (0, 1, 0), (0, 0, 1)}
$\begin{pmatrix} 1 \ 0 \ 0 \end{pmatrix} = \frac{1}{2} \begin{pmatrix} 1 \ 1 \ 0 \end{pmatrix} - \frac{1}{2} \begin{pmatrix} 0 \ 1 \ 1 \end{pmatrix} + \frac{1}{2} \begin{pmatrix} 1 \ 0 \ 1 \end{pmatrix}$
zslya
Do you know how I got this solution?
not really
$\begin{bmatrix} A | \begin{pmatrix} 1 \ 0 \ 0 \end{pmatrix} \end{bmatrix} = \begin{bmatrix} 1 & 0 & 1 & 1 \ 1 & 1 & 0 & 0 \ 0 & 1 & 1 & 0 \end{bmatrix}$
zslya
Write it as an augmented matrix then solve it by converting it into reduced-row echelon form.
aka apply gauss jordan elimination.
What was the latex notation for augmented matrix again?
We are basically just solving system of linear equations.
for this problem you can add all three of your things
to get T(2,2,2) = (1,1)+(2,0)+(1,-3)
Ahhhh
Just was confused by the name
So we are looking for a linear combination to get that vector
we are looking for the values of T on (1,0,0), (0,1,0) and (0,0,1)
Ye now I understand what she did
this may take multiple steps
Ann, do you happen to know latex notation for augmented matrix?
I don't recall if it exists at all.
there is a way to write those but it's hacky
you basically have to use an array environment enclosed in a \left and \right
ahhh i see
Write this before \begin{document}:
\makeatletter
\renewcommand*\env@matrix[1][*\c@MaxMatrixCols c]{%
\hskip -\arraycolsep
\let@ifnextchar\new@ifnextchar
\array{#1}}
\makeatother
Then you can make an augmented matrix by doing \begin{pmatrix} [ccc|c] ... \end{pmatrix} for example (This gives first 3 columns then a straight line down and then the last column)
So for example the following command will give you:
$$\begin{pmatrix}[ccc|c] 1 & 0 & 0 & 1 \\ 0 & 1 & 0 & 2 \\ 0 & 0 & 1 & 3\end{pmatrix}$$
Quick question: does x between 2 and 3 mean 2 < x < 3
or the same thing, with less than or equal to
2 < x < 3 is correct, include equal sign if it says inclusive
I need to calculate an angle between two 3D vectors in which the x,y,z of each vector will mostly, but not always be different than each other. How can I achieve this? (usecase: working on a game where the red dot with the yellow arrow is the gun, while the red dot at the top of the triangle is the target. I need the gun to aim towards this top red dot, which I believe involves finding the angle between these two vectors (or dots).
Hi everyone.. could anyone answer me why linear algebra is useful in group theory?
anyone free?
i got an assignment that i want help solving it, it's a 10 question assignment.
and eh idk what i got but im paying in uc nitro codes lol so yea dm me
it isn't money doe
β Do not cheat on tests or exams. Do not be academically dishonest. Do not offer money for doing homework assignments, and vice versa.
it isn't money .-.
Post assignment
I dont know what uc nitro codes are
well they are unchecked nitro codes lol
I dont know what nitro is, just post assignment
k
btw they are 10 questions and 120 mins, when timer ends i fail
Donate it to charity or something
Is it a test?
nop
its an assignment
teachers give us shitty assignments every day
Whats the topic?
doesn't say in title
but here they are
- 2
4
2 - 4
(choosing btw)
well i can donate like $30 to charity only cause im pretty broke
btw that's a solving with steps kind of potato
question
same thing
choosing:
1
2
4
- 4
steps
choosing:
{ 3 , - 4 }
{ 3 , - 1 , 1 }
{ 3 , 1 , - 4 }
{ 3 , - 1 }
choosing:
3
2
0
1
steps
steps
steps
btw (im asking this here because i didn't come in last 2 days cause of some fam probs and the teacher doesn't respond to any of my messages)
and assignments go to smth called assessments that help in my exam, like if i get 20 from 100 and i did the homework good, i will get like 50-60 grades
some good/bad system
bad cause its literally timed
@alpine sable is that still allowed or no
cause tbh idk shit and my professor doesn't answer to any of my messages and i only have like 1 hour left on it
Is what allowed
like is asking for that allowed
if i don't know anything? and i have 1 hour left
I mean, it's a test. People wont give you answers here
no
it isn't
1 se
sec
It's timed homework for which you want answers in an hour
@alpine sable it isn't a test
lol
its assignments but for online classes
we take classes on an app that our school bought sub in
it's zoom but better lol
every assignment is like that
@alpine sable will u please help me?
.-.
No clue what S.S. means.
Two numbers, x and y
Three times first plus twice second is 13
Hi I'm having trouble getting started with this question and I would appreciate if someone taught me how to think about them ^^^
Write that down
what question is that
^?
9
this?
Yeah
ight 1 sec
Two numbers, give them names. a and b or x and y
lol i don't understand
can u tell me the steps
I wont give you the solution, I can guide yoi
You*
.-.
how will i know the solution in 1 hour
Two numbers call them x and y
if i didn't even join session
ok
Three times first plus two times second gives you 13
what's first and second
x y?
x and y, we dont know them
Yes
ight ok
So whats the equation when you write it down? In terms of x and y
im trying but my brain isn't functioning
i just woke up few mins ago
ok so now
3 x X + 2 x Y
= 13
Yes
Thats step 1
lol this is gonna take so long
Step 2: first added to three times second is 16
and i'll not submit the assignment in time
Then fail
why .-.
ok how about this
can you solve the stuff now, and after the assignment can you stay abit or when you're free and dm me and try to explain until my shitty professor answers?
cause tbh i need all the assignments i can get cause i got some other fam stuff i need to focus on
assessments*
1 sec lemmy show u what they are
these are assessments
please?
Focus on family stuff then. I wont give you answers sorry
ok
ok can u give me a way i can solve the choosing questions
like not answers
Could have finished 1 question by now
Find help elsewhere
why are you acting like that
and 1 question in 1 hour .-.
You want solutions, not help. Find someone to solve it for you then. Giving out answers is against the rules
Sorr,
Sorry
well i will sit and understand the questions after i solve it
Ping helpers, maybe someone will. I doubt it though
<@&286206848099549185>
well i think its a gonner anyways
rip
Guess randomly. Or google it
if it took 1 hour to do 1 question it would take longer to make them all
randomly how
i will write the answers
and take pic with my phone and answer it
@alpine sable Standing on the top of the sunset cliff in OB, Jack spotted a ship. If the cliff was 20 meters above sea level and the angle of depression of the ship from Jacks's eye was 10 degrees, how far is the ship from the shore <@&286206848099549185>
π PLEASE BRO
ill try
Kk
yeah yeah
so the answer is 20/x>
so your answer is 20/cos(10)
it is not?
?
π° pls i only got 1:24 min left
that wouldnt make any sense delta
why wouldnt it
for the ship to be the base?
the shore starts from the bottom
how far is ship from the shore. if jack spots the ship from the cliff
yeah assuming the cliff is straight
its tangent that u use
to solve for the base of the triangle
im not a native speaker but i got a strong feeling im right here. could be wrong though lol
me neither and same
yeah the shore starts from the bottom
ty guys!
π
but how far away is it from the shore
i got no idea
30 seconds left
thats the hypothenuse
not the distance to the shore
π damn it's just math bro
hmm
it's just school bro
delta u in uni?
lol don't beg em, suddenly they start to feel like they better than you and act all holy. just ask someone else
$\int_{ }^{ }\frac{x}{x+3}dx=\int_{ }^{ }x\left(x+3\right)^{-1}$
Delta
do x+3-3 and split into two fractions
but have no idea how to go past this
bruh forgot the dx there
Couldn't you just u sub this?
Yes.
how does the sub thing work?
let u=x+3
Have you never done substitution?
we havent had those yet
im just bored and learnin ahead of time
i did quite a lot of those yesterday but cant say i got them to the heart
Using u-substitution to find the anti-derivative of a function. Seeing that u-substitution is the inverse of the chain rule. Created by Sal Khan.
Watch the next lesson: https://www.khanacademy.org/math/ap-calculus-ab/ab-antiderivatives-ftc/ab-u-substitution/v/u-substitution-example-3?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusAB
Mis...
that integral at the start looks like pure suffering
$\int{ }^{ }\frac{x}{x+3}dx=\int{ }^{ }x\frac{x+3-3}{x+3}$
HyperBolt
that's what i suggested, then split the fractions
Sorry im new here
the x shouldn't be there, typo
yeah thought so
$\int{ }^{ }\frac{x}{x+3}dx=\int{ }^{ }\frac{x+3-3}{x+3}$
HyperBolt
add dx at the end and it's perfect
Then you just can split x+3 and -3
ahh
hard on a phone π
atleast on a phone u can use the technique of pen and paper
and picture
not if you're on a bus
$\int{ }^{ }\frac{x}{x+3}dx=\int{ }^{ }\frac{x+3-3}{x+3}dx=\int{ }^{ }\frac{x+3}{x+3}-\frac{3}{x+3}dx$
HyperBolt
not keeping a notebook on u at all times to do some quick maths
the first part simplifies to 1 right
Clear from here @alpine sable ?
yep
show how its done after uve done it
done these with a number on top
is it x - 1/3 * ln(x+3) + C
just make the 1/3 to just 3
Then you got the exact solution
i dont know what u mean
true abs value
no abs value
u meant 1/3 instead of 1-3?
i meant 1-3
true no abs value x is x > -3
forgot about that part, it was stated yeah
x - 3 * ln (x+3) + C
ahhhhhh im stupid i forgot
no abs cause x>-3
obv you can take the constant out
$\int_{ }^{ }\frac{x}{x+3}dx=\int_{ }^{ }\frac{x+3}{x+3}-\frac{3}{x+3}=\int_{ }^{ }1-\frac{1}{3}\cdot\frac{1}{x+3}=x-\frac{1}{3}\ln\left(x+3\right)+c$
Delta
that symbol gives me the scary
forgot the dxs
It is 3 not 1/3 @alpine sable
yeah it is 3
3 ln
dude cmon how the hell did i miss that
I think it is a little attention error
$\int_{ }^{ }\frac{x}{x+3}dx=\int_{ }^{ }\frac{x+3}{x+3}-\frac{3}{x+3}dx=\int_{ }^{ }1-3\cdot\frac{1}{x+3}dx=x-3\ln\left(x+3\right)+c$
Delta
now it should be correct
can i get some help laters
Happens to even the great mathematicans
ask we are done with my problem
i dont get it i keep getting wrong answer
finite difference
200x / ((x^2) + 1)
f'(4)
i get f(4.01) being smaller than f(3.99)
so it gives me negative number
h=0.001
so
doing it the f(4.01)-f(3.99)/2h
sec ill screenshot
hello everyone !
how can i generate this sequence ?
1, 2, 2, 3, 4, 4, 5, 6, 6, 7, 8, 8,β¦
odd numbers once, evens twice?

floor(2n/3)
The function is decreasing on the posive real line
So every difference should be negative
thats a great hint thanks !
ty
Could someone help me out? I did this word problem but I donβt think I did it correctly.
@surreal lantern, I just joined this server, but trig questions are up my ally. Iβll answer this, just give me a few minutes.
Thanks so much!
Btw, bearing is the clock rotation from north
Yup this is how my teacher described it.
When sixty consecutive odd integers are added together, their sum is 4800. Determine the largest of the sixty integers.
obligatory question if this is a test or not
I would start by doing that an odd number is 2n+1, the next consecutive odd is 2n+3, and maybe try work out the sum from there? Iβm not sure how youβd do it without noting all 60 numbers tho ππ
I did that
And got this
I know I went wrong some where
But I do not understand where
Iβd try approach it with a series, calculate sum of 60 numbers with progression: 1,3,5,7,9 etc. Then take that away from 4800 and youβd be left with 120n=4800-sum of integers, find value for n and then use arithmetic sequence formula to find 60th number and substitute if you have to
Thats what I did
The sum of the integers is 900
Iβll give it a try, two mins :))
kk
I got 139 as the final answer, Iβm unsure if itβs right but I did it via the method I suggested,
Hmmm
I got 133
I used the arithmetic series and arithmetic sequences to work it out, are you aware of those formula?
Yes
What did you get as the value of n
I got n as 10
I got n as 7.5
Would you like me to send my working?
Yes
Please
I got the sum of the odd integers as 900
Iβm not sure where you got that from
2+4+6+8+10 = 30 and 12+14+16+18+20= 80, therefore I said that they increase my a common difference of 50. So, 30+80+130+180+230+280. Adding them all up I got: 930
Thatβs even numbers?
I know, allow me to further explain my thinking
The sum of the sixty of the consecutive integers would then be: 1830. Using the formula: n(n+1)/2
1830-930= 900
There are 5 integers that make up 30 and 80 respectively i only count 30 total integers in your calculation to 930. Youβd need to keep adding 6 more :))
If you add the remaining 6 digits you get 3660 which is a total of 60 integers
For even numbers*
Ohhhh
I see
Try it now, hopefully itβll work out π
@tight basin Iβm stuck on this too funnily enough, what I think you could do is differentiate first which removes b as itβs an integer, then substitute x=1/6 which means gradient function is 0 (I think), then rearrange for a. Then you may be able to work out b? Iβm not too sure how just yet
@surreal lantern, I feel like such an idiot, i certainly did something wrong
Lemme show you what I did
Itβs been a few months since Iβve done this, and this is old for me
yeah mate i got a = -13 but ms says a = -2
just doesnt say how it got -2 so kinda annoying
Sorry if I wasnβt much help
@tight basin same here I got -13, not sure how she got -2
Here is a similar question from one of my online classes
stupid
I think your teacher is wrong π¬, subbing a=-2 in the differential doesnβt equal 0
What negative two?
Yeah apparently
Wdym?
His teacher got a =-2 but we both got it as -13
I think we are doing different questions
Iβm really confused how they got that result tf
I mean I get how to obtain the second derivative but and all that but it seems strange that you have to use the second derivative
A point of inflection is just where the gradient is 0 so surely the first derivative would work too
i figured
first deriative is for stationary point
they got a+4b= 10 by multiplying everything by four after u sub in g(-1/2)
I have literally no idea where they got a+4b=10 either because I can only make it as a+b=10
Unless Iβm missing something
ye just a shitty question
Yup
They got the answer wrong though for sure because second derivative is only used to determine the nature of the stationary point right?
Though saying that a point of inflection still has a second derivative of 0
i'd say try something with noticing that if you start with 1, then plus 3, then plus 5, each interim sum would be a square number
so starting from 1, it'd be n^2, where n is the number of terms
now ofc you don't want to start from 1, and you can subtract the point where you want to start out
in this case 60 earlier, since you want to add up 60 numbers
so you'd end up with n^2-(n-60)^2 - then you could factor it out by the difference of the squares as 60(2n-60)
and n is the nth odd number starting at 1
I got the answer, it was the guy I was helping out who needed help. 139 was indeed the answer π
yeah then solve 60(2n-60)=4800, resulting in 70
that's the 70th odd number, with the 1st being 1, so you multiply by 2, subtract 1, yep 139
Any idea on how to even start solving this? https://i.imgur.com/qghbiv7.png
i dont even understand the question
@steel scaffold What's the height of the bottom triangle if the base is 1?
1/sqrt(3)?
Right, so you can get the area of the bottom triangle from base and height.
Now, what's the base of the second triangle? It's the hypotenuse of the bottom triangle. What's that length?
sqrt(4/3)?
sqrt(4)/3
Yep, which can be simplified a bit.
So, you have the base and height of the second triangle, so you can find its area.
What's the base of the top triangle, which is also the hypotenuse of the second triangle?
0.7698003589
Chai T. Rex
The base of the middle triangle was sqrt(4/3), which is 2/sqrt(3). That's the adjacent side, which is the numerator on cosine. The hypotenuse is the denominator of cosine.
So, $x = \frac{2}{\sqrt{3} \cos(30^{\circ})}$
Chai T. Rex
hmm ok i see
So, $x = \frac{2 \times 2}{\sqrt{3} \times \sqrt{3}} = \frac{4}{3}$
Chai T. Rex
Now we know the base of the top triangle, what's its height side?
4/3 tan30
Yep, and what's $\tan(30^{\circ})$?
Chai T. Rex
1/sqrt3
OK, so you have the base and height of the top triangle.
Find the area of all three triangles, add it together.
1.186775553
No, it's 2.37 something, but what's the exact answer?
https://i.imgur.com/aUe7sOj.png where did i go wrong?
Oh, I see. I think I made a mistake. One moment.
Yes, you were right.
,w (1 1/sqrt(3) + 2/sqrt(3) 2/3 + 4/3 4/(3 sqrt(3)))/2
So it has $\sqrt{3}$ in the exact answer.
Chai T. Rex
So, it'll be one of the answers with .5 in the power of three.
wdym
Chai T. Rex
yea
Chai T. Rex
yea
there are 12 triangles not 3
and there are different angles for some
not all have 30 degrees
i assume 4 4 4
wait no
It says they're similar triangles, which means the angles are the same in all of them.
oh yea
But basically, let's make it easier for ourselves.
The area of the bottom triangle is $\frac{1}{2 \sqrt{3}}$.
So, the total area is $\frac{1}{\sqrt{3}} \sum\limits_{i = 0}^{11} \left(\frac{4}{3}\right)^i$
Chai T. Rex
in that case shouldnt the second triangle have a base of 2sqrt(3) rather than sqrt(4/3)?
Let me recheck.
Sorry, computer crash.
@steel scaffold Yeah, good catch.
So, the area is $\left(\frac{2}{\sqrt{3}}\right)^2 = \frac{4}{3}$ times as much.
Chai T. Rex
So, it comes out to the same thing, but I made a typo.
No, wait, another typo.
So, the total area is $\frac{1}{2 \sqrt{3}} \sum\limits_{i = 0}^{11} \left(\frac{4}{3}\right)^i$
@steel scaffold I think that's correct.
yea i think
,w 1/(2 Sqrt[3]) Sum[(4/3)^i, {i, 0, 11}]
So, that should be the total area of all 12.
hmm i see
is there another way that I could calculate the area of all 12 without having to use sigma?
Well, you could do sigma by hand.
,w 1/(2 Sqrt[3]) (1 + 4/3 + (4/3)^2 + (4/3)^3 + (4/3)^4 + (4/3)^5 + (4/3)^6 + (4/3)^7 + (4/3)^8 + (4/3)^9 + (4/3)^10 + (4/3)^11)
The trick to save a lot of work is to notice that the sides of each successive triangle are 2/sqrt(3) times as large, so the area must be 4/3 as large as the previous.
So, you have the first area plus 4/3 of the first area plus 4/3 times 4/3 = 4/3 squared of the first area, etc.
This allows you to find the area of just the first triangle and multiply it by that.
You're welcome.
am having math problem on scaling image from all sides and keeping the corner position
this piece of code work only before rotation
preview
Determine the excise tax to be paid on a house that sells for $268,210 if the buyer makes a $25,000 down payment and the seller takes back a second mortgage for $50,000?
[7:56 PM]
A)$536 .42 B)$537 C)$533 D)$538
[7:57 PM]
so the answer is B but can anyone explain how you get the answer please?
amp12128 β Today at 8:34 PM
$268,500/500 = $537
this is all it says soo idk where they got 500 from
my exam got cancelled
π
π’
(deleted message with mod ping to remove venmo info)
CβA, f:A->B
need to prove that Cβf^-1(f(C))
so i suppose my task here is to show that for every x in c that x is also in f^-1(f(C))
and im having trouble formulating that into something more explicit than a vague gesture at the page and saying "well of course it is, look at it"
any tips?
verbally i can say that its true because that set contains all elements in A that "point" to the elements in B and that that set contains C
might as well mention the other part while im at it, need to also prove that if f is bijective then c=f^-1(f(C))
it's no more than using definitions of image set & preimage
just feels like that falls short of the task to "prove" it
i meant most of the proof involves using those definitions
for every xβC f(x)βf(C) β xβf^-1(f(C)) β Cβf^-1(f(C)) does this look right?
yes
Hi
what should i do first
this is out of context, but after I have a complex number in polar form, it's equal to z
What is the question?
then
i know those lol
im asking if i should find z first then multiply, THEN take the conjucate
or
find the conjucte then multiply
Well if you have it in a+bi form I would just multiply them together and then take the conjugate
you've already done the heavy lifting
are both ways correct?
I don't really know
I don't think so
but I may be wrong try it out
The question is (a-bi)^2 = Conj((a+bi)^2)
Yeah you can convert from a+bi to polar form
k
the radius is just the magnitude of a+bi and the angle is just arctan(b/a) I believe
since the line is on top of all
i think maybe do z*z first
then take their conjucate
That's what I would do π
Multiply first because it asks for the conjugate of the product
,w conj(z) * conj(z) = conj(z*z)
Oh nvm then
Oh hey that other way does work
so both...
man I forget how conjugates work some times damn
Indeed it does sorry not too well versed with complex
lol
Tell me what you get
What is z*
r is zero
right?
1
What is this the solution of?
i simplified the big fraction
Nvm continue
Okay cool so the magnitude is 1
So our polar form looks like this e^ix right?
but recall that e^ix=cos(x)+i*sin(x)
What value of x does cos(x)+i*sin(x) = -1?
Chai T. Rex
Yeah exactly and cos(x)=-1 when x= pi so that means (z * z)^*=e^(i * pi)
@small stag
Every value of (2n+1)$pie
Well that's only if you're a math major
Well range is not defined so we have to assume (-infi,+infi)
Around these parts we only care about first order terms and finite solution sets
consider: in how many numbers does the digit 1 appear in the hundreds place?
repeat for the other digits and the tens and units places.
come to a conclusion about how one might calculate the sum.
well you made it so that the x only appears on the left
why not add or subtract something else to both sides to get rid of that +10
Its asking for solution set
And all the answers on the multiple choice are not decimals and i keep on getting decimals and i check it online and it says decimals too
Im sorry i guess i took it the wrong way
I tried adding 4x instead and then 10 and then 5 to try out different ones like you said
I just ended up putting this cause it made the most sense with what i got
what the fuck?
none of these are correct.
the correct answer is x <= 5/9
,w -4x + 10 >= 5x + 5
Thats exactly what ive been getting
And i even started doing it different ways to get different answers to just get one from the choices
But i couldnt find any so i just put the one with 5 cause 5/9
well the thing is
all the answer options are wrong
so the correct course of action is to talk to your teacher and hope they don't double down
is 2log|x-2| = log(x-2)Β² ?
2 log|x-2| = log( (x-2)^2 ) yes
Can someone guide me as to how I can solve a simple question like this on matlab?
syms y(x)
ode = diff(y,x) == -0.0004332 .* y;
cond = y(1) == 0.005;
ySol(x) = dsolve(ode,cond);
disp (ySol(-0.002));```
This is my code so far, however it doesn't work as intended, the value it returns looks too random.
can this be simplified any further
<@&286206848099549185>
please don't crosspost
yes log(x/y)=log(x)-log(y)
I m new here
@inner zinc please familiarize yourself with the rules in #βhow-to-get-help; in particular don't multipost
Ok
any help on this physics question
Physics server, link for which you'll find in #old-network, is more suited for this
alright, I thought this was more maths based question with mechanics
is it asking for mu? i dont understand the question because of my bad english
If x=1/6 at the point of inflection on f(x)=4x^3 +ax^2, how do you work out a? If you take the first derivative you get fβ(x) 12x^2 +2ax=0, the second derivative fββ(x)=24x +2a. Sub in the x=1/6 and for fβ(x) you get a=-1, sub in x=1/3 for fββ(x) and you get a=-2. That shouldnβt happen right? What have I missed?
why is minus sqaure root of 7 an irrational number
@alpine sable you're not using your x=1/6 properly
Because β7 is an irrational number. Any non-perfect square under a radical will be irrational.
when consider inflection, you're only really interested in the second deriviative
thanks
i.e. solve f''(1/6) = 0
Actually, it would be better to say the square root of any prime number is irrational, and 7 is prime.
oh smort, thx
I'm pretty sure the former statement is still correct though.
oh and one more thing, the quotient of a irrational number divided by a rational one, is a rational number right?
Not necessarily. In fact, I can't think of a single case where that is true.
oh ok
in fact this is never true
not sure where to begin doing this, idek what the question means lol
Sure 
it's asking you to find the size of angle C
thank you
note that the given 103Β° is for angle A and is rounded.
you could apply the sine rule (which may be what they want)
since you are given all 3 sides, you can instead apply the cosine rule to get a more accurate result
thanks
why is there only one possible value of x and how, i feel like im missing smthn i didnt realize
context?
show the whole question, there's probably something earlier in the question that doesnt permit negative numbers or smthn
this
in isolation, whats written is fine
oh why not
convention
also because in the context of this question, a negative length makes no sense.
halp ;-;
It returns a value like this
which imo looks too absurd? xD
Gotta love computers
The equation solution will be an exponential, so that seems correct...
But you're going to want to simplify it to a decimal
$\frac{1}{200}e^{0.004315}$
John_Cavanaugh
Check my work
A number is selected at random from the set {1,2,3,4,...,20}. Find the probability of the following events
1. drawing an odd number
2. drawing an event number
3. drawing a prime number
4. drawing a composite number
5. drawing a number divisible by 3 or 5
6. drawing a number divisible by 4 or a factor of 20
7. drawing an odd number or a factor of 18
8. drawing an even number or a factor of 11
i need to finish my homework because my mom is gonna kill me again, so I need help in someone.
not sure about matlab, but the correct answer is 0.00500217
@acoustic crater what you need help with? which number
need a bit of help with finding the domain over which a function has an inverse, but not sure if im doing it right. The function is f(x) = (x^2)/(x^2 - 9), and i need to find the domain where it has an inverse. any help is appreciated, thanks.
well (2sqrt(3))^(1/3) = (3sqrt(x))^(1/6)
(2sqrt(3))Β² = 3sqrt(x)
12 = 3sqrt(x)
sqrt(x) = 4
x = 16
If I'm not wrong
u sure?
you can verify
I mean you plug 16 in the equation and see if it's correct '-'
what do you know about the diagonals of kites?
nothing
could you just tell me how to do it?
yeah so i gotta find the perpindicular gradient how do i do that?
use the definition of perpendicular slope
which is?
look at your notes or google yourself. I'm not gonna spoonfeed all the things you can easily google
why not?
Cause you should be able to type on google. .
i prefer human interaction
I think the problem moshill is currently dealing with is that you are not showing much attempt on trying to solve the problem on your own.
They gave you guidance, but note they will not just give the answer to you. That's not how it works here.
becuase kites are (hopefully) perpendicular, i think it should be the reciprocal of AC's equation + or - an offset
there's not enough evidence if the angles arent 90 degrees
bow wow
i put it on a graphing calculator and it worked
so how i do it?
(x=\frac{1}{3}y-\frac{2}{3}) is the reciprocal to AC's equation
bow wow
you gotta find the perpendicular gradient first
if you swap x and y back it will rotate 90 degrees
and then (i think) you square the 2 in 2/3
i'll check
no
the offset is different
welp the answers tell me to find the perpendicualr gradient
google that
Omri
Sorry I meant $C_2[a,\infty)$
Omri
No, this is calculus
oh
the hint is "integration by parts"
right
but how?
so pick one of the f'(x) to be u and the other to be dv
I tried that.... I didn't get anywhere
You get $f(x)f'(x)-\int_a^\infty f''(x)f(x)dx$
Omri
right yeah
but both terms might not converge
if you remove the offset from the other eq i sent, then y=2 will have x=-6, so the offset must be -(-((6-2))/3, so 4/3
well you know for the integral to converge $\lim_{x\to\infty}f''(x)=\lim_{x\to\infty}f(x)=0$
moshill1
Thats simpy false
simply
There are positive functions that don't have a limit at infinity, but their integral converges
Is this question solvable? I don't necessarily want an answer, I just want to know if the question is written wrong. I have been having a problem with questions not having a correct answer.
if you do an expaned version of the quadratic formula, (so ax^3 + bx^2 +cx + d)
you can make any wave like that
that's not a wave
that's a cubic
so there's no such thing as expanded version of the quadratic formula
Are yo uguys talking to me?
I was talking to bow
but you know the roots so you can write the factored form of the cubic.
then use the y-int to find the a value
Thanks
does anybody know?
What if you integrate by parts again to get something $-\int_{a}^{\infty} (fβ(x))^2 dx$
Wew Lads Tbh
You just get 0=0...
I think it would be $f(x)fβ(x)- fββ(x)fβ(x)+\int (fβ(x))^2 dx$
@half pasture where you get 0=0?
Wew Lads Tbh
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
That is mistaken, the second term is $f'(x)f(x)$
Omri
And you just get a trivial identity
Only other thing I can think of is maybe try integration by parts on $\int (fββ(x))^2 dx$ but Iβll need to actually write it all out to see if it leads anywhere
Wew Lads Tbh
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
How? $f$ is not three times differentiable
Omri
Yeah thatβs the problem
do i need geometry to learn trigonometry? sorry for the stupid question
yes
ok thank you
what's the construct called if equivalences between a and b are themselves all equivalent?
product rule in reverse
umm.... not really
can you explain it to me please?
or is there some sort of step-by-step explanation for it?
look up "calculus product rule derivation" if you want a proof
im just plunging into ODE without knowing this stuff and it felt a bit hard π¦
yes, im planning to speed-through it π
ew no
any advice where I can learn calculus?
I don't have the luxury... my exam is in 3 months π¦
bruh
i mean like ok just to put this into perspective
this is like if you tried to start solving quadratic equations while barely knowing how to multiply.
is there like a table of content/recommended book or something similar to have an overview of what I need to know to do ODE?
@vale wigeon do I need to do Calculus 1-3 before ODE?
1 and 2 definitely, 3 maybe
and what happens if the independent variable was also a part of the derrivative?
I noticed that t was there too
y*
the dependent variable*
ok... im a bit confused
of course youre confused
this is like trying to explain a particular instance of factorization to someone who struggles with multiplying numbers ;p
like
no really, i could try and state the product rule time and time again
it would be no use because it will not stick
I just skimmed it
like ok for reference here is the rule itself: $$\dv{x} [f(x) g(x)] = f(x) g'(x) + f'(x) g(x)$$
Ann
its like taking a derivative of 4+t^2 times y, right?
yes thats exactly what is on the right-hand side
lets say 4+y^2 is f(x) and y is g(x)
(4+t^2)y, differentiated
4+t^2 itself differentiates to 2t
y differentiates to dy/dt, almost tautologically
I just need to do f'(x)(g(x) + f(x)g'(x)?
"need to do" is one way of putting it Β―_(γ)_/Β―
I can't do that since I am not enrolled in calculus π¦
okay, im a bit confused at this part
how does it differentiates to dy/dt?
what do you think dy/dt even is
the derivative of y is dy/dt by definition
if not the derivative of y
