#precalculus
1 messages Ā· Page 95 of 1
Yeah same here. Being self taught is fun but often gets rocky at times
Oh well do yk the expansion of (x+h)^n
yeah that's what I mean
this problem doesn't required you to know a lot about limits or derivatives or whatnot
if you know the needed algebra theorems inside, you can solve it
Uhm have u heard of
$(x+h)^n = x^n + \sum\limits_{k=1}^{n} \binom{n}{k} x^{n-k} h^k$
Scholar Of Mysteries
@gleaming walrus
yes, I learned it to solve that problem
Yea so what do u need help with? š
I don't need help š
I was talking in the discussion channel but I can't send images there
what is that Man
what the helly
too many unknown signs and their uses
Ohh I love these, though I'm not always good with them, idk why.
the 6x - 3 should be a 6x + 3
I am not too sure what method you used but I divided the fraction, or the first term by x^2 on top and bottom and got (12x + 6 - 3/x^2)/(2 + 7/x^2) now the -3/x^2 and 7/x^2 as x approaches infinity reaches zero so those are negligble giving you (12x + 6)/2 which is just 6x + 3
I used ruffini
12x3+6x2-3 = 3 . (2x-1) ( 2x^2+2x+1)
and
( 2x^2+2x+1)/ 2x^2+7
that doens't equate though

h wait it does
didn't see the 3
k
and I used this

your work makes sense but your taking the limit of not just a fraction but 3 things, namely the fraction, cube root and the 7x
all terms must be compared together before concluding anything
the dominant behavior of this cube root is x + 1
why why
giving (6x + 3) + (x + 1) - 7x

that gives 7x + 4 - 7x which is just 4
depending on how u do it if you get a 1/3x^2 lets say as x approaches infinity that fraction will be 0
so it won't even matter you can just get rid of it
but i have 6x-3 instead 6x+3
try factoring out a x^3 inside the original cube root, which does give x + cbrt(1 + 3/x + 1/x^3), and the idea here is that the cuberoot of (1 + 3/x + 1/x^3) approaches 1 + 1/3 * (3/x + 1/x^3), which after multiply out and taking the lim gives x + 1
you probably got that because you tried to cancel something you can't
like the quadratic with the denominator
oh I see you did do that, then you should have gotten x * (something small), which is x * cuberoot(1 + tiny) now you can use linearization which I did use to figure out what that cube root would end up being, but there is an algebraic way if u want to know
its just painful
is ap precalc worth or shld i jst take normal precalc
i have the opportunity to take precalc in 10th and take ab/bc in 11th
How would we solve this
Iām in AP rn I mean I think itās a good bridge to take ap calc and get into ap exam math structures with frqs and all. and more rigor to colleges/weighting possibly
Take square root to both sides (you can do it without worries because everything is non negative)
Btw
I remembered a^4-b^4
Thatās what I got
you can do the fourth power square root on both sides so you get 2x+1 = |3x+4| and that working out is quite easy
i checked on my calculator and that should work
Looks like a fun one
U need help with this or just answer?
Guys in a differential equation, What exactly is x and y?
y is a function of x right? so like y=y(x) or h(x) whatnot. And x in an differential equation is the variable, input for the function y.
and dy/dx is just the y derivative, y'(x).
and in the image when we wrote g(y) this y in g(y) is the y in the dy/dx? so g(y) is a function which has an input of y=y(x)/h(x), and f(x) is just a function which has the input x, which is the same input y depends on?
um sorry if i dont make sense at all.
2
I get bc 4 is 2^2 and 8 is 2^3
it took me like 3 pages and 5 tries cause i tried stupid shit but i got it
I used nth root of(x^m) = x^m/n
And get same base
Then that cancels and left with 2x-1=x+1
Subtract over to get x=2
i simplified to (2^4x-2)^3=2^3x+3)^2 then just work it out to 2^12x-6=2^6x+6 and then you remove the 2 and simplify
hey guys im new and i really need help with calculus...can anyone help me...
You are free to ask your questions in #calculus like plens suggested ^^
looks like it
it has the same hieroglyphs on it
Is this what u said āif u want all solutions even complex then let LHS=aā“,RHS=bā“, so u get aā“-bā“=0, (a-b)(a+b)(a²+b²)=0, so a=b,a=-b and the last is just the quadratic so finding ex is trivialā
Anyone know a place to find a good and quick explanation of why the properties of conics hold. All the hs curriculums just dumb it down and donāt explain crap and Iād rather not read 40 pages for this.
I mean like all of the connections between all the ways to define conic sections and why cones connect to general 2nd degree equations. Figured out a lot on my own but Iām bound to miss some interesting things Iād rather not misss
Were u in NotMathClubās live
x and y are nothing special, dy is just a little bit of y (lets say y is an hour a tiny bit of an hour would be 1 second for example), and dx is a little bit of x, so the ratio dy/dx is simply saying how much does y change when we change x (dx) by a little bit. Speaking precisely if you have x, then dx is the derivative of x, same with the y. In the image you show its a bit more complicated though because we have a function f, where x is the input and a function g where y is the input, and theres no derivate weird stuff happening there but we equate it to dy/dx. Depending on how far you are in calc you may realize you can seperate the variables and get (1/(g(y)) * dy = f(x)dx which you get by just algebraic manipulation, and the right side is the derivative of f(x) and the left side is the derivative of 1/g(y), or the reciprocal of g(y).
dy/dx is read as "the derivative of y with respect to x"
now you would want to integrate after rearranging
you typically do differential equations after completing calc 2, or 3 as well
and next time use #calculus
<@&268886789983436800>
No, havenāt heard of it
Ok
Nope
Okay
OH THAT GUY. I donāt think I was in any livestreams but Iāve commented on a few shorts of his
Yep
im first
@gentle vault Hi
Hi
Hii can someone help me with this? Im not sure if this is correct
I thought thats what your supposed to do i think i got it mixed up
Im new to this stuff i just started learning today im learning by myself i dont go to school š
you guys got any youtube video recommendations for this one?
,rccw
linearity and
power rule
check out stuff from organic chem tutor
also use your space,
write stuff on new lines
+- can also be simplfied down to -
making the final result
9x^2 - 8
This Channel is dedicated to quality mathematics education. It is absolutely FREE so Enjoy! Videos are organized in playlists and are course specific. If they have helped you, consider Support:
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Your su...
ohhh okay i see thank you!!
organic chem tutor is goat
any good vid for continuity and differenciability,
and tricks for integration, highschool level to solve multiple choice questions?
Just differentiate the options if there is an MCQ for integration.
Far easier.
Also, continuity is not that hard imo.
A function is continuous if for all c in its domain, lim_{x->c} f(x) = f(c).
A function is differentiable at a point if it is continuous at it, and also smooth.
Extend it to all points for a differentiable function.
The smoothness is given by the limit of the difference quotinet.
I see you mention 'smooth' but I think that this definition is a bit dangeroous to operate with. Would be better to prove that a function is differentiable at a certain point and hence continuous at it. Smoothness is just a vague term, in several cases you can't declare a curve to be smooth at certain point without checking if it is differentiable at it.
ohhh thank youuu @urban kernel @rugged sleet ššš
do u have any videos? a short one, just for explanation works
Khan Academy (Calculus AB/BC) Playlist is good imo for beginners.
Remember, i am not recommending this for rigour.
It's for intuitive understanding.
hmm, i dont know calc, but are u saying that the continuity of a function depends on how it changes its outputs as u change the input
No.
like when your input approaches a value, the function's output also reflects that
its output gets closer to the output of f(that value)?/
Yeah..., you can say that
why though?
why does continuity depend on that?/
like isn't it obvious?
does every function not support that?
why?
A function is continuous at x=c if it attains the same value at every point in the neighbourhood of c.
ahh ok
Piecewise functions don't.
but if it breaks, there will be atleast one value that makes the function undefined
Check this example:
f(x) = x^2 if x>=2 and f(x)=2x-1 if x<2
To determine if f is continuous at x=2, you will have to check if lim x->2 f(x) = f(2)
So, for the provided function, can you comment on its continuity at x=2
its the same func srry
f is the same function defined differently for different points of domain
I hope you know how to check if limit of a function exists at a point?
uhh....... about that
you make dx, smaller and smaller right?
if lim f(x) exists as x->c then this applies that its right and left hand limit exist and are equal.
hmm
wait, how do u know which direction to approach fro
m
do u do both
what if the limit exists on one side
what would that entail.
it would be dis-continuos right
what do you mean
you take both limits
elaborate
i digress
?
what i mean is that, if we take the limit from one side, that does not like fully define the function cuz it may be dis-continuos from the other side
for a function to be continuous at a point, the left hand limit and right hand limit as it approaches that point should be same and equal to the value of function at that point
yes, so one must approach from both sides, before declaring that its continuous
right
thanks!
$\sin^2(x)+\tan^2(x)=\cos^2(x)-1$
YeetusDeletus5
try rrt first
I did
I get P/Q is 1,1/2,1/4,3,3/2,3/4
6x2=12 possible solutions
wait ||3|| is a solu
-1 works
Two repeated roots; -1 and -1/2
yea
According to desmos
When I did rtt, my teacher let us use desmos even on quizzes and tests
im new here what do i do
That depends on what you want to achieve.
i know someone taking a2 in middle school
im a freshman in precal
ik a few other kids in my school doing it (like... 3, 4 that i know of)
I wish i was
š„
damn
Iām a senior
ik u told me before
Yep
Where do I go from here?
,rccw
I would go back to line 1 and instead bring -log|x| to the left
and then apply on both sides the exp func
That fixed that. Thanks!
Went ahead and did that @exotic barn still kinda rough on this
Why would applying e^x to both sides work in this case?
The roots of the quadratic are 0 and 10 and since the leading coeffcient is positive, it's open upwards, so within the roots it would be negative
because e^x is the inverse of ln (I am assuming log means here with base e)
but you can take any base
Right⦠Knew that just need to make cheat sheets.
Thank you for your help!
Np!
what does exp mean here
oh
can you show me more of this problem
specifically the base of the log
and when u write a straight bar is that abs value?
ah nvm this was yesterday, just take away that e^x is specifically the inverse of ln(x), NOT log, but in your problem assuming the straight bars are abs symbols then you can just change log(24) and change it to log(24/|x|) giving you:
log(|x - 10|) = log(24/|x|)
And since there is no notation provided for the base it is assumed to be 10, with that being said they have the same base here so you can remove the logs giving you |x - 10| = 24/|x| where x cannot be 0 (otherwise division by zero).
Solve to get:
|x(x-10)| = 24
And split into cases:
x(x-10) = 24
x(x-10) = -24
You should know what to do from there
Also for the step where you just remove the logs, note that a log is injective making it one to one, and if you want more intuitive reasoning think of the situation where you raise a constant b to the power of log_{b}(x), which is just x, and instead of applying "e^x" you would just apply the base of the log to get rid of them.
It's important to note that because of what @exotic barn said here about e^x is the inverse of ln, and regardless they have the same base meaning its okay to remove the logs no matter the assumed base
easy question to try removed
oh it wasnt on my channel list for some reason
!status
Do I have to show steps
I guess so
But what's the issue with this exercise? Which part are you having trouble with?
Did Khan Academy mess up?
where did x go 
Oh wait, I realized that they talked about the co-vertices and not the vertices.
The answer isn't an imaginary number, whoops.
Reasoning
The first method is synthetic divison
I think
Then I got R(x)=6
Will it be (x+1)(x-4)+6
Since we know (x+1)=0 then
0(x-4)+6
Then itās 6
what does this have to your previous question
also this isn't what the question is asking for
This one
If it that I have to solve the first requirement
To get the second
but what does that have to do with the f(x+1) = x^2 - 3x + 2 image you posted
That was the second one while waiting for them to respond
To the first
they responded
they were waiting for you to say which part you had trouble with
Then I did
It was the reasoning
The wordings are confusing to me
did you do part i)
i mean b i),
there's only one i) there so i ditched the a
Itās subtracting the ālog_2 x^2
Okay
Do we just use the given and solve or I have to proof the first equation to a
wdym
you said a) was easy, so i'm assuming you did that already
b) i) is a continuation of that
solving the equation you just got
Thatās what I got
continue solving, you're not done with that yet
you've only factorised,
haven't explicitly stated the roots yet
We get x=-5/3 and 6
I see that -5/3 doesnāt work bc
log (-x)= undefined
yes
didn't really need to eval the whole thing,
just starting domain and/or log(-5/3) is undefined is sufficient
Guess what 6 works
you've also dropped the 2 in front of the log on the right side when plugging your values in
and the way you're evaluating when x=-5/3 is also bad
because you're essentially doing algebra that ignores the restriction that disqualifies it from being a solution
intersection of all arguments of the logs being greater than 0
x>0 would be the domain, yes
the way you're evaulating it
,w log(2,(-5/3+3)(-5/3+10)) = 2 + log(2,(-5/3)^2)
would actually be true
hey -5/3 doesn't work tho
because the origional equation on the RHS is not squared
oh okay
also do u say your pau part as ram?
thats cool
@tired garden
hello, can i ask you a question?
Ī»: line density
Ļ: surface density
Ļ: volumic density
These are usually used in physics/engineering
I remember them appearing on electrostatics, and also a little bit in mechanics
p=mv
Huh, that's not a density
That's linear momentum
(Sometimes I've found it called q)
And this doesn't have greek letters
Now yes š
What is it
Ļ = mass/volume
Yess
But often this is simply called d, not Ļ
(at least in my country)
g/cm^3
Thatās the unit for density
But d=vt is distance
That's just one of infinite units
??? No š
Distance = speed x time
Itās just (massās unit) per (v^3)
Is this right
It's simply "whatever unit for mass" / "whatever unit for volume"
Okay
The international systems uses kg/m³, but often you can encounter g/cm³, g/L, mg/mL and so on and so forth
Okay
But this is physics, not calculus
Of course
Okay
"centi" means a hundredth (aka 1/100 or 0.01)
Ok
jeez, vary your responses at least
you come across as a redstone repeater, just outputting the same thing over and over again
...yes I know that's not technically what they do just deal with it
dayum
he seems interactive enough to me
okay
sup
Who
fk precalc
nooo
i think someone had a rough study session
any1 know the most elegant part of precalc?
What
Wdym
Indeed, how do you measure elegance? š
Guys i made fun notes of calc like the idea of it in a fun way does anyone want to have a grasp
I'd like to see
Is bearing same as angles
Can somebody explain that question marked line only?
ignore the language cuz there is no english translation for me
Itās upper limit - lower limit
At x = 5 (upper limit) it will be
(5sqrt(25 - 25))/2 + 25/2 sin^(-1) (1) = 0 + 25/2 sin^(-1) (1)
At x = 3 (lower limit) it will be (3sqrt(25 - 9))/2 + 25/2 sin^(-1) (3/5)
ive done too many area under the curve to forget ab this š thermo fluids is killing mee
i know of exponent rules like 1/x becomes x^-1
however how do i integrate that exactly? you add 1 to the power and divide by the new power
am i missing something there
you cant divide by zero
Am a send u on dm later just leave me a reminder cuz am busy rn so sry
alright understood
Integral of 1/x is not the same as normal integration
Itās ln|x|
hello guys, Iām new here and just starting out with calculus. Could anyone suggest some good resources to help me get started?
which physics problems do you think are best for beginners to grasp the core concepts???
any resources youād suggest for learning?/
classical mechanics problems will may help you learn WAY more why calculus is needed and youāll start to see relationships that kind of usher in calculus
<@&268886789983436800>
i get into this chat and i feel like "dang, ap precalculus failed me š"
There are often people who for some reason or another try to talk about calculus questions here instead of in #calculus.
So don't assume everything being spoken about here is something a precalculus class should have taught you.
that channel isn't even showing up on my server channel list, i guess I didn't dd all of them lol
like this, i'm just confused on the syntax lol
Yeah, the server uses a Discord feature that aims at not overwhelming newcommers with a bazilion channels, but it's somewhat wobbly. You can right click the server name (above the channel list) and click "show all channels" in the menu.
Is it writing e^blah as exp(blah) that confuses you? Or leaving out the parentheses?
yeah the exp and my curriculum never used abs value
and the arrow is that just like simplification or
i can see the math it's just stuff ive never approached i guess
The arrow is an implication arrow
A ā B (B follows from A, or A implies B)
Well, do you know what modulus (absolute value) is?
like do i know what absolute value is? yes, i've just never used it graphically and i haven't done any solving with it since 9th grade lol
As you can see, the output for a modulus is always non-negative
so can an absolute value's function never have a y value of -a?
it was introduced to me in alg 1
and i think i used it in geometry a little bit in real world problems?
they introduce it but i dont think they actually do anything w/ it
idrk i don't remember lol
besides distance but thats not really using the parent function tbh
all it really is is just the distance from 0 so
f(x) = a|x - h| + k
h : horizontal shift
k : vertical shift
a : vertical compression or stretch
if a is negative, the graph reflects about the x axis
but this doesn't matter cause you can just multiply the number by a so don't mind me š
its a subjective question, which part of precalc delivers maximum results with minimal, surprisingly simple formulas or methods, like eulers identity.
Istg if I have to do this STUPID axes rotation by angle transformation again in calc I will die
Actual nightmare
Me when eigenvalues of $\begin{bmatrix} a & b/2 \ b/2 & c \end{bmatrix}$
Civil Service Pigeon
Anddd thereās a 10 second method
25 minutes of my life down the drain
what u typin
me?
@loud fossil
-.-
I hope this will help,p
So let me wrap up everything I said. So basically the derivative and the limit is is like something that is widely misunderstood upon others. For example, the derivative is mostly known as the accurate change like the accurate change that's not like like the slope. But actually the derivative is how much the velocity or the thing we're measuring changes as we as it approaches and this approaches zero meaning it's more than the accurate change. It's something related to the physics behind of the thing and not only the numbers. Like it's not just the slope it's literally the physics everything behind it. For example, so we have a car. So the car is basically transferring energy from chemical to mechanical to kinetic. The chemical part is when the car is not even moving is when the car is literally at zero zero constant velocity or the unit we're measuring it in and as it moves and this approaches zero when this mechanical and chemical energy turns into kinetic it increases and gets away from the zero. But as the friction of the ground acts as a external nerving uh force that's like how Newton Law said that any force second law actually that any force acted by another force is the only way the force can change. It decreases and makes it approach zero. So when we solve something like 3x^2 the derivative is basically when
we manage the power we're basically measuring how much it approaches zero and then when we are multiplying the constant it's basically how much like it's getting away of zero. So it's basically widely just connected to physics more than just numbers and abstract proofs. It's basically the way we should look at look in it when we actually solving real life problems instead of just looking for how much is the rate of change. We should look of how much does the thing change as it approaches and this approaches zero. And this gives us more accurate and more reliable answer that can be used for any operation then if we're using it for only the slope we're basically just like we're basically just like um finding an answer for the temporary state. And when we say it's an accurate estimation we're just saying an accurate estimation for for example a two points and then that we combine but it's actually a way to solve this problem forever like without actually having to measure every single part of the of the graph. So the misconception is that if the thing that we actually believe is that derivatives that means we need to actually measure every single small part while we're only measuring how much the thing changes as it approaches and this approaches zero. And when we zoom in into something we're just seeing the little slope of the thing instead of seeing how much is the change over certain time for a more reliable answer we use the derivative that is actually the real versus the misconception which is just a dumb idea of what we see that's only used for hard like thinking cuz if what it was actually true we'd sit years trying to find the derivative. And basically the the thing changes as the the the the certain type of graph changes is what changes the way and method we use for example power rule, chain rule, etc. And this gives us an accurate estimation that helps us understand everything very well. I hope you enjoyed what I said.
its prolly a light
Iām an algebra 2 student and I was curious whatās ahead, I looked at this, and ngl im kinda scared now..
lol itās a reduced blue light led
derivative is a graph of instantaneous slope
youāre overcomplicating it a lot
In physics for position functions your input is usually a time
so the derivative of that position function throughout a time interval would just be dp/dt
meters / second
which is just velocity
Velocity with respect to a time is acceleration
and instantaneous slope is just the slope over an extremely small interval as the length of that interval approaches a finitely small number
So just this
What ur saying is technically kinda the same as what i said
Thats what i said
But am saying
How do we find this conctusie sle
Slope(
This is not what ur gonna take its just a theory
<@&268886789983436800>
Did I do something wrong here?
I donāt think so
Qait
Itās gonna be 13sqrt2/2 - 13sqrt2/2 i
Oh ok, thanks phew
Ohhh, that's how you do it.
Thank you so much! That was much simpler than I thought it was going to be.
DONE WITH CONICS YAYAYYAYAY I HOPE I NEVER SEE THESE EVER AGAIN OMLLLL time for sequences and series hope this ain't harderš
gulp wow
once I do s&s I will be DONE with precalcš
Sequences and series
ohh
I acronymed it cuz I said it msg before
how hard would you guys say sequences and series is compared to conics and paras
sequences and series can be so much harder, oh boy the sigma notation, and learning how double sums work, and triple sums, and recursive sums, and deriving all the equations for a{n} and S{s} and then even more, its a lot, way harder than conics imo.
its so much more difficult
although if your not self study it will probably be around the same difficulty
im self study so I had to learn it in so much depth, and rederive where all the formulas come from and develop new techniques to invent new ones
because you have to learn all the basics which go by fast, for the single sum, and nail the notation down with practice and the rules for it and why they work.
and then move onto double sums
then triple
until you get the pattern and you can do quadruple on your own
thats how I did it atleast
and then taking a sequence of numbers and thinking about it as a function and finding first differences, second, and third, and so on
and then finding the degree of the polynomial based off of that
for f(x)
and rederiving the equation using the form Ax^3 + Bx^2 + Cx + D for example
and you would do so by setting up a system of equations and setting the polynomial to the sum of the first term, first two terms, first three terms, and first four
so @viscid thistle it can get kinda crazy if you mean to go deep
definitely worth it though because now I look at it and be like, oh this stuff is easy
as when I first saw it I couldnt do it at all
alr, wish me luck thenš so far I litteraly just started 2 minutes ago so
imma stuydy for 4 hours straight
the start should be rather easy, the formulas for a linear sequence are just simple and the sum is simple as well and creative depending on how you want to intepret it if you do research that, same for geometric, once u get into sigma notation and that type of stuff though then you will be able to invent those types of formulas
the weirdest thing I do till this day is factor out a sigma
this basically
since the sigma literally just means add and its all linear u can just do that
so if the sum of x's was 10 then would it be a(10) +b(10) = (a+b)(10)?
yeah
because if u set 10 to u so 10 = u you will have au + bu = u(a+b) @viscid thistle
thats one way u can think about it
nice, thank you
@orchid urchin yo arithmetic sequences lowk rlly fun
nvm just sequences
im aboutta do arithmetic
wait I think I can do this now
let me try it
im not sure if I got this right at all since I litteraly had no idea what was going on so I made up a thing on how to do it lol
51?
,w \sum^{3}{i=1} \sum^{4}{j=2} (i+j)
whooop
You seem to be off by $6=1+2+3$, so maybe recheck somewhere there
Civil Service Pigeon
oh also ill mention if u can do sequences and series on a good level u can begin discrete calculus
which is lowk easy
and calculus too if u can do that
Now try to find an explicit formula for the sum of (-2)^i from i = 0 to n
i personally would recommend not using the geoemetric series formula
and learn about telescoping series to solve that
Its also wrong to so dw
$pi$
š£
Uh idk
Wat
3.14sqrt(-1) or psqrt(-1)
Can someone help me with understanding the use of tangents and normals in conics?
The ones done were in class, didnt get it someone mind explaining 7, 8, 10, 12 my dms are open anytime.
THE ALGEBROS
Ok but do you want it explained here or in DMās?
Im In precal honors bro
Sure dms would be great
Precal reviews a lot of algebra
ive noticed that, i was never great at algebra bcs i never focused in class lol
I sent you a message R
Oh⦠thatās⦠not great
What do you think for 12)
hope you're doing well, here is the question:
i struggle to understand the change of base rule of logarithms. even though i made a proof for it myself. i understand the proofs but they don't really explain anything. they just show you why the rules work algebraically but i want to know the logic behind the rule.
i don't understand that why you get a completely different base when you divide two logs, with the same base.
i asked the same question when I tried to make sense of adding up rule. I asked the question of why you multiply the input values when you add up logarithms with the same base? How does this actually work when all you're doing is summing exponents up? and why doesn't this work when you add up logs with the different bases? I was desperate by answers, so i asked that question to ChatGPT and it told me this:
"You are trying to mix two different counting systems into one system."
that made kinda sense but my gut says that it didn't explain anything mathematically, thus this is not really reliable or understandable.
can you tell me the logic of base of logarithms?
there are literally too many rules in logarithms and it feels kind of frustrating to make sense of all them.
i could just use them as tools which will save me a lot of time and would be actually smart since I need to pass the universty entrance exam but i have a lots of time ahead of me plus that's not really how i study.
It's a bit hard to know what will help when you already have a proof and that doesn't convince your gut ...
But ... suppose the only way you know to calculate powers is b^y = exp(yĀ·ln(b)).
Then, instead of looking for log_b(x) as a solution to b^y = x, you're solving x = exp(yĀ·ln(b)) which is the same as ln(x) = yĀ·ln(b).
would you like to learn my proof
Another way to look at it would be to say: Logarithm functions are just arbitrary multiples of ln -- after all, these all satisfy f(xy) = f(x)+f(y), by linearity.
And we define the "base" of one of these functions to mean the input that happens to map to 1.
feel free to share it
also, are you comfortable with exponent rules? because if you are, log rules are really not far behind
do you understand that logs are basically reverse exponents
i am
ok so as tropo said, try to turn your log rules to use exponents
like, what does log(xy) = log x + log y mean?
what does that look like if you had to write it with exponents instead
a^??? = xy
a^? = x
a^? = y
a^??? = xy = a^? * a^? =
i know this is far from valid math but you would think about that rule like this
the ? is why logs are helpful
anyways with exponent rules you would have a^(? + ?) = a^??? = xy
so ??? = ? + ?
thats why a log xy = log x + log y
yeah, actually that's why these rules are called as "the properties of logarithms" because you can prove them by the very own definition of logarithm and exponent's basic properties.
loga(x)=y <=> a to the power y = x
i assume that all the properties are basically the interpretation of this definition
well yeah log rules are just what happens when you use exponent rules
and write them with logs
just checking, are you saying that angel's explanation is one you already know but doesn't satisfy you?
Yeah, that goes through so many steps that it's understandable if it doesn't produce much intuition. I would instead start just with the definition of log_b(a) try to derive the fraction at the end of the calculation:
log_b(a) is the solution to b^x = a.
But b is c^(log_c(b)), so this is the same as c^(log_c(b)Ā·x) = a.
Now take log_c on both sides again, giving log_c(b)Ā·x = log_c(a).
And now you only need to divide through by log_c(b) to isolate x.
sorry for intruding guys but uh... are ALL of these answer choices wrong or am i just not understanding
yeah
ok i don't really understand what you are asking
you know log rules exist because they are just exponent rules written in a different way and you ask why that is?
uhhh looks very wrong yeah, these look like 3-3sin t, not 3sin4t
so would you like me to try explaining a different way, that helps visualize these properties intuitively?
is that your ask?
i think my problem is about the logic between the base
you mean like the change of base stuff?
here's how i like to think about it:
but before i proceed, let me clarify some vocabulary to be rigorous
if we say "three fives make fifteen", the "make" here implies that we are adding the 5's together
i am going to use the same language, but i will use multiplication instead, since we are working with exponents and logs
so in this case it would be "three 5's make 125"
make sure to always think about multiplication as our "building action", not addition
when we say log_b c = n (aka b^n = c), we are essentially saying that an "n number of b's make c"
does this make sense so far?
to "visualize" it you can think of the b's as objects, grouped into boxes, with n of them in each box, and c is the value of the entire box
@young spire ping me if you're comfortable with this visualization and ill proceed
i was already comfortable with these actions
just checking
ok so
lets say we have as in your proof log_c a and log_c b
picture a as a giant box, picture b as a small jar
log_c a is how many objects fill the box
log_c b is how many objects fill the jar
so log_c a / log_c b is basically the number of objects in the box, divided by the number of objects in the jar
what is log_b a? the number of jars that go into the box
isnt that just this?
i didn't quite grasp the situation
chatgpt told me something similar to this, refering to the ratio
what in particular do you struggle with? can you point to something more specific?
the thing that i struggle with is that how do we get to the base b
like, why does this ratio lead us to log_b(a)
maybe write it as exponents
lets try a specific example
so log_2 512 / log_2 8
imagine 2 as a ball
i can fit 9 balls into a box, which i will use to represent 512, as 2^9 = 512
similarly, i can fit 3 balls into a jar, so the jar is 8
log_2 512 is how many balls fit in the box
log_2 8 is how many balls fit in the jar
so what is log_8 512?
that would be the number of jars that fit in the box
does this help?
when you divide logs, dont you divide the exponents
i dont understand how the base just come in to the solution, i guess the base matters only if you try to write it as another log
edit: ah, i think so? depends on what exactly you mean. that is what we are doing here in this example
do you at least follow my intuition
perhaps we can figure out how to explain away the confusion through that example
how did we directly come to this
the problem is here
well, we said log_8 512
8 is the jar
512 is the box
since 8 x 8 x 8 = 512, 3 jars fit into the box
and that is log_8 512
so log_8 512, in our example, can be visualized as the number of jars that fit in the box
why do we find how many jars would fit in the box
because the entire point of this was to help with visualizing the concept
you dont have to do this at all
no no, like
loga(x)/loga(y)=log?(???)
when i first saw the rule, i asked to myself that if i was finding this rule, what would i do to divide two logs? as it turned out, i was struggling to determine the base.
its easy to prove the rule when the base is determined and all you need to explain is why ... is equal to ...
so we can either pretend we know the left side and figure out the right side or vice versa, which way do you wanna approach first?
we should try to find the left side (base) and pretend to know the right side (input)
ok
so let's pretend that, once again, 8 represents the jar, and 512 represents the box
so log_8 512 represents the number of jars that fit in the box, which we know is 3
but let's say we don't measure this directly, we don't just shove the jars into the box and count
let's say we have to use some kind of measure, like volume
we say, for instance, the jar is 1 liter, the box is 3 liters, or something like that
except instead of measuring in liters, we measure in balls
what is a ball? doesn't matter, literally any amount
so hypothetically, if we set the ball to be 2, as in our previous example
I wonder if some of the problem might be that you expect the rule to work like "we must always rewrite this to that when we're doing calculations". That wouldn't be a helpful way to look at it; it is more "these two different calculations always yield the same result" -- a plain fact that you can then do with what you want. It can sometimes be useful to replace one with the other or vice versa when that happens to make something you want to do simpler.
we can find log_8 512 by first measuring the amount of balls that fit in a jar, then the number of balls that fit in a box, and this can be a proxy to find the amount of jars that fit into the box without directly measuring jars inside the box
the ball could be any other value and this would still work
you can try this with the ball being sqrt2
and that's why the general base c just appears, and can be anything
Does anyone have AP Precalc exam prep materials that are either legit or leaked? I need resources for final exam and especially help for FRQ#2 part Bii and C
Just do past papers
there's only so many and FRQ 2 i dont understand
Well, do as much as you can
What FRQ#2? What year?
Try to find a video on YouTube explaining it, instead of just doing it @hybrid leaf
?
I can help you out for Bii. What did you get for Bi??
Your answer in Bi is your rate of change per month (slope) for the equation you have to compose in Bii
By what is given, 25 is your intercept (at t = 0) soooo you can make up a slope-intercept form equation and solve for x = 1,5
sorry, I meant to say t, not x lol
Honestly I might be the only one who does this but lets say a problem has me run a logarithimic regression then for the rate of change question i just switch to linear for the same data and take the rate of change there
cus frq 1 and 2 r both calc so i can do that
My bad.. I meand Bii š
It's the explanation ones - I don't know what they are looking for. For part C as well, I understand the concepts but its the specific phrases I don't state that lose me the points
Yeah. I am talking about Bii
For example when it says determine the domain, technically the question doesn't say you have to find the domain but i believe that you are expected to find it
gosh typo for the second time Biii
Oh š
mb
@hybrid leaf D is a quadratic that opens down and increases on [0; 4]. A_t is a secant line to the quadratic
So concluding from that, why is A_t always less than D(t)?
Example of a concave-down quadratic and a secant line
Okay so itās asking you to connect the idea of a vertex of the graph to the domain. In the context of plays, it makes no sense for it to decrease. The maximum in a concave-down parabola is when the rate of change changes from increasing to decreasing soooo do with that as you will
Yeah... I can do the explanation part but I guess my main issue is not not kowing how to solve the problem... it's writing what they want
should I just write everything I know in hopes that one of those is what they want
Well, if you know the explanation, write it down??
I basically gave you the entire answer
that the function has a maximum so the domain is from 0 to where that maximum is?
Exactly
Iād say the explanation is already enough, but if you want to include saying the maximum, go for it. Better to be safe than sorry loll
Anyway, happy to help)
If you have any more questions, feel free to reach out here
Me and @crimson wraith need help with math
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
Uh
Just post the question.
Read the message...
#precalculus message
isnt the answer ? 4/9 ?
do Eqn 1 Ć· Eqn 2
(x^2y^2)/(xy^2) = 36/18
x = 2
sub x = 2 in Eqn 2
2y^2 = 18
y^2 = 9
y = +- 3
therefore x/y is +- 2/3
thats the perpendicular distance formula
you can prove it with vector geometry later on
Correct
I got 50
correct
The long way is
Make a slope formula
And use the distance formula with sqrt((sum of x)^2)+(sum of y)^2)
How would u make an equation of this parabola
Presumably it is a parabola with vertical axis (without assuming that there isn't a unique solution), so plug those three points into y=ax²+bx+c, giving you three equations in a, b, and c that you can solve.
You can also wing it less systematically by writing down a function for the line through (8,0) and (14,18) and then adding an appropriate multiple of (x-8)(x-14) to make it pass through (12,16). That's a simpler calculation but perhaps more conceptually confusing.
It's just like by quadratic general equation y=ax^2+bx+c
Itās y=-ax²+bx+c
<@&268886789983436800> MrBeast
Am I right
I also noticed (8,0) is on x-axis
You can write it in that form too.
And I got x=20 also
Or y=-(1/2)(x-8)(x-20)
Even I can use mean value theorem on (12,16) and (14,18)
Case 1: x = x - 1 => 0 = -1. Doesnāt work
Case 2: x = -x + 1 => x = 1/2 (only real solution)
1/2.
1/2 ± i/2
1/2 ± (1+sqrt2)i/2
,w x^8 = (x-1)^8
Just got that
Wolfram writes the imaginary parts weirdly, but sqrt(3+2sqrt(2))/2 is the same as (1+sqrt(2))/2.
then immediately you have that $x = \left{ \frac{\zeta}{1 - \zeta} \right}$ with $\zeta = \exp(2\pi i k / 8)$ for each $k = 0, 1, 2, 3, 4, 5, 6, 7$
And there's a pair of solutions I missed with imaginary part ±(1-sqrt2)i/2, which I really should have exepected -- they correspond to an 8-pointed star with edge length 1 rather than a regular octagon with that edge length.
howd you solve it if not with the roots of unity
Since x^8 = (x-1)^8, I know in particular that |x|=|x-1| which is only possible when the real part is 1/2.
very nice
So I was looking for regular polygons with number of sides dividing 8, and side length 1, where one of the sides could be the line between x and x-1.
x^5-1 has complex solutions that is with radians
yes you can use roots of unity
$x^5 - 1 = 0$ has solutions $x = {\exp(2 \pi i k / 5)}_{k = 0, 1, 2, 3, 4}$
,w x^5 = 1
did i mess up somewhere 
oh well

i will ping Moderatrosand you will be banned.
LMFAO did he get banned š
Practice makes perfect!
i was correct
idk why wolfram alpha decided to omit a solution
||square (1+i) first||
Add then square it once more.
just binomial expansion
for all terms except first and last
and you find every part that is imaginary
oh wait I lied its 0
use the polar form
Yes
chinese
Itās -16,384+0i
So itās 0
I like solving this
I get log_2^a (log_2^b (2^1000)) = 1
seems about right to me
^
yeah, and then 1000/b = 2^a
I thought itās 1000*[log_2^b^2]=2^a
well you can keep going in layers, like the first layer which is log 2a and all that stuff = 2^0 = 1, and then the second layer you get the log2b(2^1000) = (2^a)^1 = 2^1, then third layer you get 2^1000 = (2^b)^(2^a) = 2^(b * (2^a))
It's a bit odd here but equating the exponents from the last step we get, 1000 = b * 2^a and then since a na db are positive you just identify all powers of 2 that divide 1000, and sum em up to get 881
the only hard part is actually finding all the pairs and summing them
which this would also get you there, just because it comes from the law property log_{a^b}(c^d) = d/b
I got 128
Okay so
Iāll start with log_2^b (2^1000) = 2^a
Move the base under 2^a
Now itās 2^1000 = (2^b)^(2^a)
Same base can cancel
1000=b^(2^a)
We know 1000 is 10^3
So itās 10^3=b*(2^a)
im kinda confused on this step, it would have to be 1000 = b * (2^a)
10^3 can be 5^3 * 2^3
Then itās
5^3 * 2^3 = b*(2^a)
You see
b = 5^3=125 and a=3
yeah so far I agree
its for all possible values of a+b though
thats just one pair
a = 3 and b = 125 which sums to 128
a = 2 and b = 250
a = 1 and b = 500
501 + 252 + 128 = 881
neat relationship btw
Thanks
How would u derive a=2 and b=250
I just checked a = 1, a = 2, a = 3, etc
lol
im surprised thats a comp math problem, ig it makes sense though since u have to find pairs of numbers and sum them up which is unusual but I feel like it is very straightforward
de moivre's theorem
1+i=sqrt2cis45
so sqrt2^28 * cis(45*28mod360)
and then u get there
mod is modulus
cos+isin
NOOOOO COMPUTER SCIENCE explodes
Oh
if x % 2 == 0 then "even" end
except for 0 = x
you can also take everyone's advice and square it once, (1+i)^28=((1+i)^2)^14=(2i)^14 which as you know is not going to be imaginary
Yep
forgot one more rule, x>=0
I never remember where the = and > goes
it can't be 0 because 0 is odd nor even
and it can't be negative
in general u can do their tactics but for more weird problems on that I suggest doing de moivre's theorem
if u cehcking if its a even or odd num
how
show proof
idk I don't do discrete meth
hmmm
what about -0
let m, n be any positive integer where m>n
2m-2n=2(m-n)
since it is divisible by 2 and m-n is positive, it's a thing yeah
2n-2n=0
-0 isn't real
oh i see what I did, I assumed that it couldn't be even or odd because it was neither pos or neg
it was satire
discrete math is fake
wait
oh yeah? Then whatās (0i)^2, huh?
0^2*-1 btw
I had a headache trying to read this what
Modulo* The modulus is also called āabsolute value,ā while the modulo is the one that finds the remainder
Or I might be wrong
The modulus might also be the specific number you divide by to find the remainder, I guess
Or something like that
pop quiz, whats the modulus of a complex numbert
sqrt(a^2 + b^2)???
nice
for a complex number a + bi
yeah and if u think about it its the same for x,y coords
non complex or rect coords
True
whatever u want to refer to them as
makes it easy to convert them to polar as well
Mhm
yall tryna read an exploratory note?
what is this
idk bro
a dyadic kinda polynomial and quadratic sequence
Plot the points on a graph of the factored polynomial $p(x)=4(x-6)(x+3)(6x-1)(1x+2)$
emiya
how much detail is required?
Thats easy stuff
Its called precalculus but its easy
Just algebra at that point
Yes
it is left as an exercise for you to prove
Just use epsilon delta definition
It would js be annoying to expand
Guys, is there any website kinda thing where i can find calculus questions regularly??
Daily Integral
what is a squeeze theorem
What do you mean "falling for"?
The embed looks like the site is probably more than a bit snarky, but just seeing the embed itself should give you more than enough clue to understand Alberto's point without actually following the link ...
Hey chat how does one determine the direction of a parabola (or which variable changes) from this state?
Um write the equation with x square and its term on side side while keeping y on other side then its something like
Y=1/2(x)^2+5x+59
This proves the parabola is opening upwards and u can find its vetex by using (-b/2a,-D/4a)
Then find the y intercept and trace the graph
Also if x is squared term parabola opens up or down and if y is squared it opens left or right depending on conditions , here it opens up as x square is positive