#help-33
1 messages · Page 83 of 1
Merineth
now we'll group all the x² terms, all of the x terms, and all of the constant terms
but
Can't i just put in x = 0
that way A is gone and we get B
B = 4/3 - 1
B = 1/3
that works
$x-1 = Ax^2 + Ax + \frac13 x + \frac13 -\frac23 x^2 -\frac43$
Merineth
the general method for this is:
- expand:
$x-1=Ax^2 + Ax + Bx + B + Cx^2 + 2C$
group all like terms into a single coefficient:
$0x^2+1x-1 = (A+C)x^2+(A+B)x+(B+2C)$
cloud
by comparing coefficients, we find the following must be true:
- x² coefficient must be 0:
$0 = A + C$
- x coefficient must be 1:
$1 = A + B$
- constants must add up to -1:
$-1=B+2C$
cloud
I think A = 2/3
you can either solve this as a system of equations from the start (hard but doable) or you can use substitution to make it simpler (in this case we know everything except A)
Yeah!
I put in B and C
and then i saw that i could make x = 1
Giving me an easy equation
$\frac{\frac23x + \frac13 }{x^2+2} + \frac{-\frac23}{x+1}$
Merineth
That should now be in partial fractions
we now get back to the integral: remembering to add 1 to the front from our earlier division, we can now integrate this
oh nearly forgot the +1
$\int 1 +\frac{\frac23x + \frac13 }{x^2+2} - \frac{\frac23}{x+1}$
Merineth
we can also split
$\frac{\frac23x + \frac13}{x^2+2} = \frac{\frac23x}{x^2+2} + \frac{\frac13}{x^2+2}$
cloud
now we split into 4 different integrals and solve (mostly by substitution)
i think you're confusing integrals and derivatives
Woops, yeah
I'll do those calculations on paper
gets a bit tricky with the bot
I got a question about F(x) tho
if i have
$f(x) = \frac{2x/3}{x^2+2}$
To find F(x)
do i just take 2/3
and find primitve of that
Merineth
Merineth
and then find primitive of these two ?
this one is solvable by substituting u = the denominator
remember that when we're substituting, we have to divide by the derivative of u
$\int \frac {2x/3}{x^2+2} = \int (2x/3)ln|x^2+2|$
Merineth
So this is wrong?
that is wrong
:(
I'm not too familiar with substitution. Why do we have to divide by the deriviate of u?
$\int \frac {2x/3}{x^2+2} = [(1/3)ln|x^2+2|]$
I'll just remember to do it
Merineth
Merineth
because substitution is the chain rule in reverse
I had a suspicion it had something to do with the chain rule :3
can i go even further than this?
that's nearly everything, we still need to integrate (1/3)/(x²+2)
aaaaaaaaaaa i missed that one
One moment haha
$x + \frac{ln|x^2+2|}{3} + \frac{1/3ln|x^2+2|}{2x} - \frac{2ln|x+1|}{3}$
Merineth
That should be it
unfortunately that's not a correct integral of (1/3)/(x²+2)
when we have a u-sub we have to get everything in terms of u, with no leftover x
and divide by deriviate of x^2 which is 2x
$\frac{1/3}{x^2+2} = \frac{1/3}{u} = [(1/3ln|u|) / u']$
That would be my thought process
Merineth
we would be left with (1/3)/u * 1/2x, with nothing to cancel the 2x with
when we have these types of integrals we can instead rewrite:
$x^2+ 2 = 2(\frac{x^2}{2} + 1) = 2((\frac{x}{\sqrt{2}})^2 + 1)$
cloud
that's our denominator. then you take out all the constants to the front and u-sub u = x/√2
we're trying to turn it into the form
1/(u²+1) because that integrates to arctan(u)
if we have integral in the form 1/(x²+a) that's close enough to 1/(x²+1)
that's a formula that includes the u-sub as a hidden step
you can just apply that formula directly
That is the only formula that provides arctan
the derivative of arctan(x) is 1/(x²+1). by the fundamental theorem of calculus, the integral of 1/(x²+1) is arctan(x). the formula above is using that + the same u-sub i showed above to make a more useful/general formula
$[\frac{1/3}{2^2}tan^{-1}(\frac{x}{2})]$
Merineth
But it says a should be squared?
or nvm i guess i get it
$x + \frac{ln|x^2+2|}{3} + \frac{tan^{-1}(x/\sqrt{2})}{3\sqrt{2}} - \frac{2ln|x+1|}{3}$
Merineth
there we go..
+C
I need to get some rest now before i die
this has to be the hardest one i've ever done
painfully hard
none of the individual steps are especially hard (once you practice them) but partial fractions problems can get really long
I’ll just have to practice more tomorrow I think
Def need a break now
Thanks for the help ;-;

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Yo
I need help with prooving the complanarity of vectors
My vectors are A(1:0:1) , B(0:1:0) , C(2:1:2)
Now i dont know how i am supposed to handle the 0
like its 0r
so thats zero
but what then
Im trying to solve it with the gaus algorythm
So its
I r + 0 +2t
II 0 + s + t
III r + 0 + 2t
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Hi, trying to solve this probability q
Suppose that two players A and B take turns rolling a pair of balanced dice and
that the winner is the first to roll at 7. If A rolls first what is the probability A will win?
I can arrive at (5/6)^(k-1) * (1/6) which is the probability where k is the number of roles but unsure of how to proceed from here.
@hollow moth Has your question been resolved?
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,, 2^{2x+1}-17\cdot 2^x=-8
Akira (fumo)
I've began but stuck midway
ill show work
,, (2^x)^2 \cdot 2 - 17 \cdot 2^x = -8
let $u = 2^x$
now it's $u^2 \cdot 2 -17u =-8$
Akira (fumo)
then what
solve for u?
2u^2-17u+8 = 0
so $(2u-1)(u-8)$?
Akira (fumo)
yep
np
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factor out log_5(x)
that would be incorrect
would there be no solution for when i say that the first factor = 0
how are you reaching that conclusion
5 - log_5(x)^4 = 0
log_5(x) = 5
log_5(x) = 5^(1/4)
you missed the power in that second line
just one more step after this
yep
where's 11 coming from
use approx instead of =
wdym by cancel the exponent
yes
use something like 4th-root or exponents instead of 4 next time
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h=\frac{\left(100\right)^{2}\left(\sin30\right)\left(\sin30\right)}{2\cdot9.81}
h=497.556 (should be 127.4)
Why am i not getting the same result (using desmos)? 😅
Maybe degrees vs radians
Edit, yeah its radians, thanks! :D But man thats messy written out by the person, this formula doesnt make any sence without adding Degree*0.0174533.
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Is the answer B?
sounds good to me
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,w 10 = 15+22x-5x^2
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hello i need help with excel math
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Alina wants to make keepsake boxes for her two best friends. She doesn't have a lot of money, so she wants to make each box described so that it holds as much as possible with a limited amount of material.
For Jen, Alina wants to make a box with a square base whose sides and base are made of wood and whose top is made of metal. The wood she wants to use costs 5 cents per square inch, while the material for the metal top costs 12 cents per square inch. What is the largest possible box (in terms of volume measured in cubic inches) that Alina can make for Jen if she only has $30.00 to spend on materials? (Round your answer to three decimal places.)
I can’t figure this out
whats 9 + 10?
how does that relate
its a question
19
<@&286206848099549185>
AND why are you asking qn
sorry my calculator said 21
what
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nvm thank you for the help
💀
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I forgot how to do the substitution method
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17x^6 + 73x - 315 / 0,2 - x^7 = 0
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
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Hello what would be correct if they ask me for the first derivative
Should I simply it by the double angle identity
both are correct
And when they ask me to find a tangent in a point 0, then still it doesn’t matter?
simplifying things makes easier sure but they have the same meaning here
Thank you!
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guys small question
since for charged condutors, electric field lines are normal to the sufraceat every point
we know that electric field lines can curve as well
so if a field line is normal to the surface then bends, is it still perpendicular to that surface?
.
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Can I say this diverges because if the harmonic series or is it not enough? Do I have to use integral test?
Harmonic is fine
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Can a true patriot fact check this
I think this should be cos^2(x)-sinx cosx?
Which?
the numerator since I assume you multiplied the numerator and denominator by cosx -sinx yes?
yes, I was gonna say that I forgot to write down paranthesis but I did do cos^2x-sinxcosx
ah ok you just forgot it there
I think something fucked up here
why? I took a factor of 1/2 out because of the double angle
1/2(cos(2x)+1)-1/2sin(2x)
although I'll say this is under a bunch of domain restrictions that it is possible that the function won't have the same antiderivative
in a calc 2 class, I am assuming everything is integrable and smooth
I mean it should turn out the same
can you show
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thrd line is bad
but sin is in denominator
yes
$\frac{3}{sinx}-sinx=2\Leftrightarrow \frac{1}{sinx}-\frac{sinx}{3}=\frac{2}{3}$
Joanna Angel
can you see it ?
oh yea
now, multiply by 3sinx
and you get euqations like quadratic one
$\frac{3}{sinx}-sinx=2\Leftrightarrow \frac{1}{sinx}-\frac{sinx}{3}=\frac{2}{3}\\\Leftrightarrow 3-sin^{2}x=2sinx\Leftrightarrow sin^{2}x+2sinx-3=0$
Joanna Angel
then you can substitute: u = sinx etc
CN you explain this substitution?
ok when you use new vriable u
then you get a quadratic equation like:
u^2 + 2u - 3 = 0
you know how to solve it ?
then, you can factor it, or use the delta formula
gotcha
cool
how did you know to multiply by 3sin at the top
seperate question ^ cant tell if I did smth wrong
it was oobvious fo rme, since, 3 and sinx were both in denomiantors
your new equation is sinx + 1 = cosx ?
yes
what did you do in second line ?
squared
it is wrong
first all you shud us eparenthesis
and second
yo do not know
i fboth sides are positive
so no
it wud be denmied by teacher
whats wrong if they are netative
-2^2 is still positive
look, wait =
$\left( sinx+1 \right)^{2}=cos^{2}x\Leftrightarrow sin^{2}x+2sinx+1=1-sin^{2}x\\\Leftrightarrow 2sin^{2}x+2sinx=0\Leftrightarrow sinx\left( sinx+1 \right)=0$
Joanna Angel
bu tperosnally i wud negate t my students
since, it requires chekcing
in the orignal
anyway
you forgot parenthesis
finally you got :
sinx = 0 or sinx = -1
Why you make me hate math

@gleaming pecan so are you saying
because we don’t know if its positive
we need to plug it back into equation ?
yes
isnt it bc squaring removes solutions
or adds extra solutions
so we need to check which is valid
what does it have to do with positive
sometimes squaring adds , how to say , foreign roots
flase roots
yes extra rotos you said
i say : obce pierwiaskti 🙂 in mhy native
so
i prefer to not deal with them
so if you sqaure, you must be caerful
itis even more important if it coem sto inequalities
but you have got onyl equations so far
that is another way :
$sinx+1=cosx\Leftrightarrow sinx-sin\left( \frac{\pi}{2}-x \right)=-1\\2cos\frac{\pi}{4}sin\frac{2x-\frac{\pi}{2}}{2}=-1\Leftrightarrow \sqrt{2}sin\left( x-\frac{\pi}{4} \right)=-1\\sin\left( x-\frac{\pi}{4} \right)=-\frac{\sqrt{2}}{2}\Leftrightarrow \\x-\frac{\pi}{4}=-\frac{\pi}{4}+2k\pi\text{ }\text{ }\vee \text{ }\text{ }x-\frac{\pi}{4}=\frac{5\pi}{4}+2k\pi\\x=2k\pi\text{ }\text{ }\vee \text{ }\text{ }x=\frac{3}{2}\pi+2k\pi$
Joanna Angel
I used formula of the form:
$sin\alpha-sin\beta=2cos\frac{\alpha+\beta}{2}sin\frac{\alpha-\beta}{2}$
Joanna Angel
my solution does not require checking original equation, if all is calcualted correctly.
@sleek crater Has your question been resolved?
sorry had to go cuz driving but thank you so much
yw 🙂
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ugh does anyone know how to prove this?
I tried using an example function where F(x,y) = f/g and finding the gradient of that but I get it in vector form idk how to put it in one thing like this
what are the domain and codomain of f and g
Well this form is a vector as well
idk man ngl
The numerator is a vector at least and the /g^2 can be viewed as a single term so it can be factored from the vector
hmm yeah that's fair that makes sense, idk how to get it in that form tho I couldn't rearrange the terms after I did it
Try to extract a 1/g^2 from both the terms
yeah I did that
Then the gradient of f and g should be (df/dx df/dy) and (dg/dx dg/dy) assuming f and g are both two dimensions
But I guess it’s also not specified what dimension f and g are
Also I’m using d but I’m referring to partial derivatives
huh so I let F(x,y) = f(x,y)/g(x,y) and then I found Fx and Fy and let those be the components of the gradient
Yeah that sounds right
but I got <fxg - fgx, fyg-fgy> /g^2
Try to turn that into the differences of two vectors now
The numerator
Break that single vector into two in a way that makes sense to you
Also did you remember the chain rule btw
Like you need to have f’ and g’ somewhere in there I’m pretty sure
Unless you meant to add the primes and forgot
Or I guess the prime notation is bad since f and g are multivariable
Oh wait that’s what you meant by fx and gx
The partials
Ok I see now
Nice
how do I prove that it works for any number of variables?
do I just say the result holds for any number of variables or
Well I guess for infinite dimension it would be different but for n dimensions you can just make them functions of n variables
X1, x2… xn
Then do the exact same thing
o I see that's smart thanks
I don’t know exactly how to do it with arbitrary or infinite dimensions
But I assume that finite dimension is almost expected
Cause you’ve probably never worked with infinite dimensions in calc 2 or even calc 3
Like most likely you are just working with functions from Rn to Rn
In fact as far as I know the gradient is only defined on finite dimensional spaces
huh so I said F(x1, x2, ..., xn) = f/g and then found Fxn (partial derivative of F with respect to xn)
You get something else when talking about banach spaces in general I think it’s called the frechet derivative
not sure if that's enough but ig it works ?
Well the gradient of F would require you to have a partial derivative in all the dimensions
for a function of n variables I wasn't sure how to show that besides taking Fxn tbh
I can't exactly take Fx1 then Fx2 etc etc
Yeah it becomes more cumbersome
I almost wonder if you can perform induction on the number of dimensions
Do you have product rule for gradient?
Like if that’s a given then you could also try using that
Actually I think another easier approach would be to prove that the quotient rule applies to any given coordinate of the vector
Like consider x_i
And the i-th component of the gradient
If you show that the I-th component of the gradient of f/g is equal to the i-th component of the vector on the right then you are also fine
And in that way your method of using xn is fine just to be pedantic I would use a different variable than n
Cause essentially you just want to argue component wise that they are equal
Definitely don’t use induction that wouldn’t help
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i have to calculate cardinal function for this data sets
this is the formula
but i honestly forgot how to do it
this is what I think we have to do
l_o = (x-x1)/(x_0 -x1)*(x-x2)/(x_o-x2)
L_1 = (x-x_o)/(x_1-x_o) * (x-x2)/(x_1-x_2)
L_2 = (x-x_o)/(x_2-x_o)*(x-x_1)/(x_2-x_1)
is this right
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Given a geometric progression (an) has a1 = 3 and 20a1 - 10a2 + a3 reach the smallest value. Find the 6th number of this progression
try writing whole expression in terms of a2
a1 = a2/r and a3 = a2*r
Idk if this will help or not but atleast try
Yes
Doesn't seem to help
I think now you have to differentiate the function and find its minimum value
What is "differentiate the function"?...
dy/dx
And just know that differentiation of x^n is (n)x^(n-1)
It'll become a1(2q-10)
Ohhhh
Alternatively you can also find minimum value at vertex of this parabola
Ohhhh
Still don't really get it..
Do you know how to find vertex of a parabola
a1(20+2q-10q??)
Oh

I got it now
Ty ty
So
a6 = 9375?
Maybe
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this is just c and d right?
Yeah
awesome
my notes define it in a pretty wordy way
just wanted to make sure
ty
.close
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$\int\sin x\cos x\ dx$
Hazwi
when i do u sub for u = sinx i get 1/2 * sin²x+c
but when i do it for u = cosx i get -1/2 * cos²x +c
were you going to ask whether they're equal or not?
no i'm just asking how that is possible
like getting a different answer for the same integral depending on how you choose "u"
1/2 (sin^2(x)) + C is also equal to 1/2 (1-cos^2(x) + C aka 1/2 - cos^2(x)/2 + C
and that 1/2 gets "absorbed" with the C
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Hey what properties does the relation {(a,b):a,b∈ℤ|a≡b(mod5)} have on ℤ?
It could have reflexive, transitive and symmetrical or only one of them, or none of them, or two, I'm not sure.
I'm a bit unfamiliar with mod, maybe someone can help me out
$a \equiv b \mod 5 \iff 5 | a-b$
tales
So we know $ 5 |0 = a-a$, so $a\equiv a \mod 5$
tales
So I have this rule for reflexive right?
a≡a(mod5)
But isn't it not reflexive for a = 6?
you mean $a \equiv a \mod 6$?
tales
Oh no, hmm
So how can I know that this rule a≡a(mod5) is true for the relation?
I thought I can put in a value for a and test it but that's probably wrong?
Is this the definition you are using?
What is the definition of $a\equiv b \mod 5$ that you are using
tales
"means that each element in the set is related to itself. In this case it means that for every a in ℤ it holds that a≡a(mod5)."
No
okay is the definition wrong?
That is the definition of a reflexive relation
Yea I want to know what the properties are from the relation and I wanted to start with if it's reflexive or not
You have to show that $a\equiv a \mod 5$
tales
But first, you have to know what $a\equiv b \mod 5$ means
tales
Is it a mod 5 = b?
'-'
Sorry 😂
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Okay what I've understood so far, a = b (mod 5) is a - b = 5
So a = a (mod 5) is a - a = 5. In the set of the relation are values for a and b, for example a = -10 and b = -5
So it's -10 - (-5) = -5, which is not 5 so it's not reflexive?
Or what is wrong in my calculation?
your definition is wrong
5/(a-b)?
$\dfrac{5}{a-b}$?
tales
@foggy atlas Has your question been resolved?
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why is the derivative of x^2 = 2x
like I get the power rule or whatever you call it
okay
but surely (d(x^2))/dx = dx/d
yea
nothing more
but why does that work
like surely the gradient would just be divide function by x
like 7x has gradient of 7
and x^2/x = x^2-1 = x^1 = x
the power rule is based on the limit definition of the derivative
gimme one sec to just catch up
I'm pretty slow so gimma a min
so you're telling me
you can work out derivatives
using limits?
no that can't be it
im telling you that the derivative of x^n is given by limits
nothing more
nothin less
you asked me why it is like that
well that's why
okay
can you help me with something else
hopefully
I'm still new to like calculus and all that so what is this
The limit definition of a derivative
ohhh
Emphasis on definition
Because it is the limit of the secant line between two points on the curve
It's basically slope approximation (rise over run) in the limit that run (given by the variable h) approaches 0
ok several questions because I truly am horrible at this
what is the secant line
is that like the function
sec(x)
Derivative of f(x)=x^2 is the best example to start with
ok
Secant line is the line between two points on a curve.
Correct. Nothing at all
pure mathematical amazement
Are you in a calculus class?
Oh. Well good job making it this far but you kinda glossed over the most fundamental concept in all of calculus. Kind of what the whole thing is based on.
yea my online friends kinda showed me it once
and then just went on about derivative of constant = 0
then derivative of ax = a
then he taught me power rule
In your words, what does a derivative of a function give you? What is its purpose?
the rate of change
Very close
The instantaneous rate of change at a given x.
difference being?
Same difference between a secant line and a tangent line on a curve
You can have an approximation of the rate of change at x by picking two points close to x. That's basically the slope of the secant line of those two points. But using limits to get the tangent line precisely at x will be the instantaneous rate of change
Yeah. Pretty much right
The derivative is the limit to a perfect approximation of rate of change
I can do any derivative with this
Yes
Wow indeed
Some derivatives are harder than others though and you'll need to learn some techniques, but x^2 is a nice and easy start
but is this good
so I replace f(x+h) now
this?
with lim obv
no way
tysm
that was exciting ngl
Early calculus learner here 
aw thanks
You can try x^3 and x^4 if you like. Maybe find a pattern
sqrt(x) would also be a good one
I know the power rule, I just didn't see why it was 2x and not x
although I still learned this rule
so that's even better than the power rule
What math are you taking right now? You understand functions very well. I feel like you must be in trig or precalc
You can try proving power rule using definition of limit, but it's not obvious
What math are you in?
What's your class learning?
Just made the cutoff for discord haha
yea
ik
I broke the rules a bit but joined this server at 13, also started using this a lot more at 13
Well you have a great understanding of functions. A lot of people really struggle with the notation
thanks
If you know geometry and trig, you really should be in a more advanced class
yea we don't have classes yet
But that depends on how well you know the material they plan to teach you know
we in the uk have to wait till like 14/15 to do some exams
Oh that's a shame.
yea ik
Keep studying then. You're doing great
Ping me if you ever need help. I respect your talent and hope you continue to enjoy math.
Best server
You have an obvious skill at it.
thanks
I just love the beauty of it at the same time tho
like infinite series and all that
and how there are still so many mysteries
The more you learn, the more you will realize how little you know
It's a crazy feeling
Same. Soon as I learned division and square root, I thought that was it. That was every button on my calculator.
Yes. But I'm older.
yea, exactly
You learned calculus earlier than I did. Your growth beats mine
thanks
"I can see further now that I stand on the shoulders of giants "
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help. i dont know how to get the equation.
do you know how to get slope?
and do you know how to get the y-intercept?
yes. it is 4
then you have the equation of the line:) $y=mx+b$
PajamaMamaLlama
where m = slope and b = y-intercept
i caan get it in y=mx+b but it wants it in point-slope form.
its y=1/3x+4
but thats not point slope form
@paper raptor
@paper raptor how abour 0,4
(you don't need to ping every time) and that works plenty well 
sorry
now, point-slope form is as follows: $y-y_1=m(x-x_1)$, plug in and bob's your uncle :)
PajamaMamaLlama
so its y-4=1/3(x-0)?
yep!
thanks
who is bob
his uncle
"Bob's your uncle" is a phrase commonly used in the United Kingdom and Commonwealth countries that means "and there it is", or "and there you have it", or "it's done". Typically, someone says it to conclude a set of simple instructions or when a result is reached. The meaning is similar to that of the French expression "et voilà!".
it's an idiom
ohhhh average UK ppl
that's why US >>
not UK :), just a fun expression to say
well I'm sorry about that
your sorry im british?
mhm
but we are better then the US. we got W health care and W free schooling
where is your free healthcare.
hmmmmmmm....
but do you guys have joe biden
yeah....
what's wrong with good old joe
the leader of your country
not sleepy joe
who relies on chocolate icecream every sunday
He's a Trump fan, trying to look like Trump too
mf needs a babysitter
(y = \frac{1}{4}x + \frac{7}{4} - 1), (y = \frac{1}{4}x + \frac{7}{4} - \frac{4}{4}), (y = \frac{1}{4}x + \frac{3}{4}).
$(y = \frac{1}{4}x + \frac{7}{4} - 1), (y = \frac{1}{4}x + \frac{7}{4} - \frac{4}{4}), (y = \frac{1}{4}x + \frac{3}{4}).
$(y = \frac{1}{4}x + \frac{7}{4} - 1), (y = \frac{1}{4}x + \frac{7}{4} - \frac{4}{4}), (y = \frac{1}{4}x + \frac{3}{4}).$
Illumiant
NOT BORIS JOHNSON
GRACE
$[y = \frac{1}{4}x + \frac{3}{4}]$
Illumiant
@still temple Has your question been resolved?
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how do you prove the power rule for derivatives?
I tried and failed with this new limit thing I learned
oh
it very basic
but sure
I just lerned limit
the thinks that look like 9's are a's
i think that right
that doesnt seem right
wait i think i misread
is it your assignment to prove this, or are you doing it for yourself
the proof is less trivial than I thought so if its for class there might be other useful context
oh ye
sorry there's meant to me a plus in (x-h)
no
like just the power rule
(x^a)' =
whatever
but it is a class assignment to prove why this works?
I wish I could say yes, but I am super new to calculus
oh
binomial theorum yes
i think
maybe not actuakky
yea
i didnt watch the video, but this is the binomial theorem version of the proof
you should be able to follow
yes
ok
$\delta$ means "change in" usually
$\Delta$
so its just a small change in x, which is what h also is
i used the wrong delta in my first message, the triangle one is the one i want
oh
$\delta$ is also for partial derivatives
so you know how by default you have y = f(x)? When you take the derivative you are taking it with respect to x (change in slope on the x axis)
but you dont have to do that
if you had some function like f(x, y) = xy, you could take the derivative with either respect to x or y
hmmm
which are called partial derivatives
probably can find better resources on khanacademy or pauls online notes
although if you are just doing power rule, I dont think you should skip to it
iirc its a calc2 topic, and you would be in calc1 or precalc
I don't do calc, I just learn for fun
so I don't know what I am
I know most of precalc I think
well, i would definitely take a look at that khanacademy video i linked, its the standard binomial theorem proof of the power rule
any other questions?
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i need help to undertsand something about transposition. I read that this formula can be a triangle.
pl
-----
R x A
and i can rearrange that to get what i need. what i don't understand it why the example above moves the A left first
what can't it move the pl over right away? the rules of transposition say it must be the opposite ? so wouldn't it become
R
-- = A
pl
@vast jolt Has your question been resolved?
@vast jolt Has your question been resolved?
@vast jolt
still here?
your example explains in detail the process of solving for a certain variable
the triangle method is a quick one used when you need to do stuff fast
the actual rule for transposition are as shown
usually we keep the variable we solve for left
the example moves A from right bottom to left top
so you would have RA/1 = ρ1/1
We can write anything as a fraction by putting 1 below
1 = 1/1
2 = 2/1
167 = 167/1
then he divides with the assembler of the unknown Value
which would be R
he divides both sides
we do this to ''get rid'' of the assembler
but what i don't understand, is if i use the triangle rule, i can simply always move the top over withouth changing it.
and get the correct answer
.
the official explanation behind that rule is the steps used in the example
for example if you were in a formal examination that required you to reason your course of action
you couldnt just say the triangle method
why do the move A first? do they always move the denominator, get rid of that, first?
we move A because we want to solve for A
at the top here it says ''to find a formula for A''
If you wanted a formula for ρ1 you'd move ρ1
ok, but why is it not allowed to just move the pl over when that is going to bve correct?
why would you move ρ1?
that is incorrect
because if you move ρ1 you would have
ρ1 1
-- = --
R A
because A is at the bottom
the triangle shows that pl will never be divided by anything. so i am confused why this "quick" method somehow violates the rules of transposition?
but gives the correct answer
it doesnt violate any rules
but it is not like
a formal reasoning
if an exercise asks you to use the transporation rules
you'd have to use these steps
that i can understand and i'd not question that.
i'm just cannot seem to see how transpostion takes a weird route to a solution the trianlge says is evident.
as far as i can see, in any example of a triangle formula, you never divide the top and just move it.
and you get the correct solution?
yes
b
----
a x c
that is my triangle
wdym opposite
the rule is if you go over the = it swaps place or -/x///+
so it would go under a?
i'll show the whole thing
ohh
and you wanna know
why the symbols dont change?
when the letters cross the = ?
okay
