#precalculus
1 messages · Page 312 of 1
this is pre calc / trig functions ig
so i solved it and got sin theta > 1/2
and b/w 0 to 2pi there are 2 solutions which are pi/6 and 5pi/6
$$ (0,π/6)∪(5π/6,2π)$$
Zyzzbrah
this is correct answer tho
how can i represent it in this way?
after finding out the solutions
If it is just those 4 solutions put it in a set
Wait...
Your theta in (0, 2pi) doesn't really make sense
okay so i solved the equations first then plotted the graph of sinx and took a line parallel to x axis with y=1/2 and marked the points intersecting it
its principle solution (0 to 360)
oh yeah ik these
If you are trying to say theta is an element of the interval (0, 2pi) you need to say like it is on the left
thats what im saying the answer should be just [pi/6 and 5pi/6]
Then just write the solution set {pi/6,5pi/6}
yeah ikr but its not in the options
i mean ik the correct answer
So what are the options?
Do you have a picture of the options and or the original question
i closed the site
but fuck it
i solved the question
all that matters
,w solve 2sin(x)^2 -5sin(x) + 2 > 0, x between 0 and 2pi
- 2
Yeah it isn't only 2 solutions is probably why
yeah
anyway thx
for taking ur time out
what do you algebraically? I am pretty sure that is the only to do it. sin(2x) = 2sin(x)cos(x) comes from sum identity for sin.
what is the range 1/x
Use your asymptotic behavior
What is the horizontal asymptote of 1/x
y=0
so can you say the range is y=/0
Yeah y ≠ 0
wouldn't you use the quotient rule on that?
I've been doing derivatives all day nom stop lmao
It's just ingrained in my mind
My bad
Hey guys
I'm thinking about not taking Precalculus next year and studying on my own
Does a good book cover all of this?
sin 2x= 2 sinx cos x
what country are you from
there are loads of good books tbh
R - {0}
I'm having some trouble with approaching this situation. I just not sure ir it'd be possible to find the 77th term without it being so time consuming. I also don't know why exactly n is only less or equal to 3.
use the formula from T3 to T7, after the T6 you can see that the sequence starts again from 4, 5, etc
and answering you doubt, n is >= 3 because for n = 1, T1 = 4 and for n = 2, T2 = 5
Oops, in my text, I meant to the if not I greater or equal to 3, but I understand why now.
This sequence is basically repeating values of 4, 5, 3/2, 1/2, 1. From term 1 to 5. And those values repeat again from term 6 to 10. This mean that my 77th term would be 5, knowing that sequence repeats every 1-5 terms
yeah
its correct
Alright got it 👍, thanks for the help @lofty sage
What's a good precalc book?
like what kind book do you want, my entire text book for precalc was online btw
if u want it
I was reading some Stack posts and found titles of old school precalculus books. So idk if I want one of those or just a some other recent book. The point is that I do want to have solid foundations whilst not being overwhelmed by seeing zillions of exercises. Yeah, I want exercises, but not those kind of mechanical ones
if i have a binomial expansion of (4-x)^1/2
for what values x is the binomial expansion valid for
is it mod x < 1/4 ?
no, it's |x| < 4.
I need help with this question under pre calculus II
square both sides and when u get cos^2x u can substitute it for 1-sin^2x
okay lemme try
squaring may generate extraneous solutions (especially since sin(x)-1 is non positive)
so you'd need to be extra careful
I'd actually recommend rearranging the equation to
sin(x)-cos(x) = 1
and apply harmonic trig identities to express the LHS in terms of a single trig function
okay ,thnx.
there are also videos like from UNC on youtube teaching precalc in like 6 hours, that could be helpful. are you in America?
Yeah
yeah that video is litterally the entire class let me see if I can find it and send it. The only problem is that its kinda short but for concepts you dont understand you can just review on youtube too
Learn Precalculus in this full college course. These concepts are often used in programming.
This course was created by Dr. Linda Green, a lecturer at the University of North Carolina at Chapel Hill. Check out her YouTube channel: https://www.youtube.com/channel/UCkyLJh6hQS1TlhUZxOMjTFw
⭐️ Lecture Notes ⭐️
🔗 Part 1 - Functions: http://lindagr...
at least as a review its pretty helpful in my opinion. I just took precalc this year and this video is pretty much the exact same
Interesting. I’ll check it out. Thanks @viscid thistle
It’s pi/2+2pi(n) for any n integer
That gives some of the solutions, but not all.
can someone help me with this?
have you made any progress so far?
nope, can't think of anything
have you ever done things with quadratic sequences before?
probably not
maybe the words "first differences" and "second differences" may ring a bell...
there is still a way to do this if not
let $u_r = Ar^2 + Br + C$ and either set up a system of equations directly involving the first three terms (hard) or do some nonsense involving first and second differences anyway (easier mechanically but harder conceptually)
Ann
oh
I think I got it
thanks
so I have to do
7=A+B+C
19=4A+2B+C
37=9A+3B+C
and find values right?
that works, yes.
https://tutorial.math.lamar.edu/
I like this website for learning calculus
Welcome to my math notes site. Contained in this site are the notes (free and downloadable) that I use to teach Algebra, Calculus (I, II and III) as well as Differential Equations at Lamar University. The notes contain the usual topics that are taught in those courses as well as a few extra topics that I decided to include just because I wante...
does anyone have a folder or something of a bunch of quick trig limits questions to practice identities etc
trig practice problems?
this simplifies to x^2 - 0.5x, right?
the textbook I'm using has this coefficient 2 in the solution and I'm just wondering if I'm taking some crazy pills and have failed to understand something critical
The following error occured while calculating:
Error: Undefined symbol x
Photomath is the #1 app for math learning; it can read and solve problems ranging from arithmetic to calculus instantly by using the camera on your mobile device. With Photomath, learn how to approach math problems through animated steps and detailed instructions or check your homework for any printed or handwritten problem.
Thar you go dude
(x+2) (x^2 -0.5x) = x^3 - 0.5x^2 + 2x^2 -x
= x^3 +1.5x^2 -x
so no
true, though I can't quite understand where that 2 comes from
if (2x^2 + 3x - 2) = (x+2)(x-0.5), then why isn't
x(2x^2 + 3x - 2) = x(x+2)(x-0.5), but instead 2x(x+2)(x-0.5) ?
because (2x^2 +3x -2) is not (x+2)(x-0.5)
That too
its 2(x+2)(x-0.5)
Could also use synthetic division to divide numerator by denominator
Yep
yes
shows that I've been practicing mostly with 2nd degree polynomials with the a-coefficient of 1 😄
yup
I don't like when the a coeff is not 1 so I always divide everything by that
so it becomes 1
makes sense. I'm guessing that in this example, it wasn't divided by 2 since that way you can use the quadratic formula with nothing but integers
yeah most likely !!
i have a screenshot from a class i took
gimme a sec to find it
thank you
yeah limits involving trig functions
here ya go
oh wait those are derivatives
oops
i misread your question
ahhhhhh
i mean derivatves are a type of limit so they're still good practice 😉
one good limit problem i know is the following
although its kind of well known
find lim x--> 0 sin x/x
and also another one
find lim x--> (1-cos x)/x
do you know anywhere i can find like a bunch of them? are there any folders online
but i appreciate it very much thank you still lol
Hmm zlib might have some books on it
i found a couple online
this one has some (although probs not the most reputable lol)
The trigonometric functions sine and cosine have four important limit properties:
also this video has a bunch of them from orgochem tutor
This calculus video tutorial provides a basic introduction into evaluating limits of trigonometric functions such as sin, cos, and tan. It contains plenty of examples and practice problems.
My E-Book: https://amzn.to/3B9c08z
Video Playlists: https://www.video-tutor.net
Homework Help: https://bit.ly/Find-A-Tutor
Subscribe: https://bit.ly...
u can just do them before he does the sol
103 trigonometry problems: from the training of the USA IMO team | Titu Andreescu, Zuming Feng | download | Z-Library. Download books for free. Find books
and if u don't get it u can watch him go through it
There’s also this https://usa1lib.org/book/640448/28a134
Trigonometry Workbook For Dummies | Mary Jane Sterling | download | Z-Library. Download books for free. Find books
See above
What do I google for this to find something to help me learn to solve it? I'm not understanding how my teacher is explaining it, to the point where I don't even know what to type in to find a video showing somebody solving this type of problem
I get that it's the difference quotient, and I know it, but I don't understand how to plug in the given interval in or anything like that
Search up diff quotient on YouTube I guess
integration of 1/(x-1)^3/5 (x-2)^7/5 dx
help this question is making me feel like dying
isn't the average rate of change from k(5.5) and k(12) just the slope between those points?
i think so
it is $\frac{k(12) - k(5.5)}{12 - 5.5}$, and everything needed to know to calculate this is given in the problem
Ann
I'm out of school and haven't taken a college math class yet, so I'm not even sure if this is exactly the right channel. Dot products were never brought up, so I'm absolutely stumped by them. I'm trying to figure out machine learning right now, and this is one of the steps. From my understanding and 2 days of Google searches, the dot product is just a way of multiplying two matrices?
So I'm supposed to be getting the dot product of these two matrices, but what I'm not understanding is why. According to a Khan Academy video, the dot product is a human construct and was chosen pretty arbitrarily as the standard. But how does that work? I understand how to get a dot product, but I can't find anything about what the dot product actually represents compared to elementwise multiplication
And I'm just more confused, because the dot product exists for both vectors and matrices? It represents the distance between two vectors, so how does that relate to a matrix?
Terminology: What your screenshots speak about are matrix products, which are not usually called "dot product".
(One can think of the dot product between vectors as a special case of matrix products, but there are some subtleties required for that which it will not make you any wiser to care about at this stage).
Oh yeah, that's getting me some more specific results
So the short nice story is that a matrix can represent a linear transformation between two finite-dimensional vector spaces, each with a chosen basis (the side lengths of the matrix correspond to the dimensions of the vector spaces). If you take two linear transformations and chain them together, the matrix that represents the combined transformation is exactly the matrix product of the matrices that represent the transformation you started with.
However, the underlined terms are probably not familiar to you yet, and you'll need to learn those first before you can really appreciate why the matrix product is useful and why it has been defined the way it has. There's probably no royal road to that, other than grabbing a book (or similar source) on linear algebra and start from the beginning. The first few chapters should take you a fair way.
(And then the topic will belong better in #linear-algebra).
Thank you for the help! I'll look into those a bit more
First simplify the definition of the function using a well-known trig identity.
critical = d/dx
when = 0
i get these
and idk how those cancel out to 0
since if lets say 1 + -1 = 0
but idk
There's a sign error in your derivative.
(But you shouldn't be using derivatives if the is only __pre__calculus, should you)?
where?
What is the derivative of cosine?
oh my god
ok im just stupid, thanks for pointing that out
ive been stuggling though this for hours
hey idk if my brain is fried from doing hw all day but- is this not the right answer??? i thought the domain of all exponential functions was (-♾,♾️) ?!!??!
Looks right to me.

If in a rational function, the curve crosses a horizontal asymptote, what would the end behavior be, would it still approach the asymptote?
<@&286206848099549185>
@opaque bear it's (0,inf)
use the fact that the integrand is of the form (f(x) + f'(x))e^x for some choice of f(x)
you can derive a formula for the integral of (f(x) + f'(x))e^x by considering the derivative of f(x)e^x
dont really know any way to motivate the solution though
Got the solution
the function from the right will approach the asymptote, but its limit can either be positive infinity or negative infinity
the two functions $f(x) = \frac{1}{x}$ and $g(x) = \frac{1}{x^2}$ show what happens really well
findingsouth
Karaly, please don't ask that in every single group
@marsh solstice sorry just curious
also you probably shouldn't just give out answers :/
what should i attach more?
something like "maybe you could try to rewrite this in terms of some sort of substitution?"
and then the sqrt is the natural choice and it's obvious from there
okay I will take care of it
Is it possible to repeat a function a fractional number of times? For example f(f(x)) is 2 times
The short answer is no
Probably because you’d need a new definition of “applying f to x n times” that extends the domain of n to other real numbers…
Which is, although possibly consistent with what your f is, often uninteresting🗿
For example if f(x)=x+1 then I can define applying f n times as x+n which is consistent with our original definition…because applying f^1/2 twice will give the same result as applying f once
But for more complicated functions like f(x)= cos x, I doubt such a generalisation exists
the notion of "functional square root" is a thing but it doesnt exist for all functions
I was planning on using the W function/productlog
well supposing you can, W^-1(x)=xe^x so I would maybe try the easier task of generalizing f(x)=xe^x by looking at f(f(x)), f(f(f(x))), ... to see if there might be a way through that first, then if you find something you can plug a number in, make it negative
Anyone got any thinking questions for combining functions grade 12 advanced. Not too hard but can possibly be a test question. I want to practice
For which numbers $a$, $b$, $c$, and $d$ will the function $f$ defined by $$f(x) = \frac{ax + b}{cx + d}$$satisfy $f(f(x)) = x$ for all real $x$?
BenJr
Doesn’t this question have infinite solutions
Yes (if "infinite solusions" means "infinitely many solutions"). It's asking how to distinguish those (a,b,c,d) that do have the property from those that don't.
Note that "all real x" means that some would-be solutions need to be discarded because because there's a single x that leads to division by zero even though f(f(x))=x for all other x.
If −7<x≤6
determine a and b for the inequality :
a<3x+8≤b
Can anyone help me out with this?
Try sketching a graph of 3x+8 in the interval from -7 to 6.
contour integral, how?
that goes not in #precalculus
🤦♂️ sorry mate. I guess I am exhausted, I haven’t been sleeping well lately.
wrong channel
anyone good at polynomial division and can hop in a call for a couple minutes?
@viscid thistle do you still need help with this?
Yes
huge delay but ok
okay so do you know how to evaluate one function at a point when you're given the function in this format (i.e. as a set of input-output pairs)?
like, if i asked you to evaluate f(-2) for example, would you be able to do it?
Yes
right
and do you know what it means when we add, subtract, multiply or divide two functions?
Yes
ok then what exactly is the issue here?
you seem to know everything you need to know for all of these exercises.
I do not know what it wants me to do here
it wants you to calculate the given expressions or conclude their value is undefined
for example, (f+g)(-3) = f(-3) + g(-3).
you told me you were familiar with this. is that actually the case?
oh, my bad, you took "point" to mean "point on the xy plane"...
that's not what i meant
sorry, it's common in higher math to refer to numbers on the number line as "points" when it is convenient
but coming back to this, you are able to evaluate f(-3) and g(-3) and then add them, yes?
Yes of course
So how would I evaluate the point in the function
??
Can yo ushow me an example
am i understanding correctly that you are asking "How do I evaluate f(-3) and g(-3)?"
No
then what are you asking
How do you evaluate a two numbers in a fybnction
...i don't understand your question.
Can you show me an example
ok sure here's exercise 51:
(f+g)(-3) = f(-3) + g(-3) = 4 + (-2) = 2.
is this what you were looking for?
i mean... yes
Then you add it
that's how you evaluate a function that's given like this
How do I solve this question: suppose you have a square with side lengths a and b which is inscribed in a circle with a radius of 10 cm whats the highest area the square can have
figure out the largest square you can inscribe in the circle and find the area of it
did you mean a rectangle
200
"How do i solve this question" "200" 
"Helpers"
Meant max area of square would be 200 un squared
can anyone help me with this? I keep getting 2 * cuberoot(4), and it gets marked as wrong
I get that too.
Oh ok it must be a mistake in the test
b
I need help with this question.
??
what even is this
"Find the equation of a hyperbola given this equation of a hyperbola"
theres nothing to find???
sorry I sent a wrong question?
ok
@last folio do you still need help with this? sorry i only saw this now - was busy irl
yh
yh
ok then are you able to apply the law of sines here?
bad handwriting + bad shape for root symbol + silent introduction of the variable x
does x stand for angle B or angle C?
angle B
ok then write B and not this strange "x" that came out of nowhere
but yes you are correct angle B is indeed 30°
okay
are you able to continue?
no
you know two of the angles in your triangle.
yh
is there anything else that you can calculate from this?
ok, so what can you calculate from this?
great then do so
Angle C = 105 degrees
are you able to finish this exercise now?
are we going to abandon the previous problem now?
after we've walked through like 90% of it already?
no
there's more to find ?
of course? there's still that third side that you haven't found.
and instead you choose to throw another, unrelated problem at me.
sorry bout that.
line A B
yh
how do I calculate for it.
you've used the law of sines once
you are definitely able to use it again
unless you refuse to do so on principle
sounds about right.
I appreciate your time helping me bless up.
If $x = t^2$ then $t = \sqrt{x}$ Then you substitute that value for t into the equation involving y and t to get an equation with only y and x
Tiessie
Basically solve for t in terms of x
Then plug that t equation into the y parameter
If you have to use a graphing tool they give you to graph a function, and that tool only lets you graph integers, do you just have to start plugging in random numbers and hope they end up being integers?
For example let's say you have to graph f(x) = 2(x-6)^2+2, and the graphing tool they give you only goes up to 20 on each axis, do I just have to plug in each number between 1 and 5 until I find an integer <20?
Who are "they"? Do you not have a pencil?
online class
which would say something like "Graph this function" and you'd have to use the tool they give you on their website to submit your answer
well this function in your example is given to you in vertex form and the vertex in this case is at (6,2) so just plug in numbers to the left and right of that?
right and since 6 is the axis of symmetry I'd only have to worry about one side right
and then I plugged in 0 and got 74
which gave me the 1-5 for numbers to check to be <20
also in this case any integer you plug in will output an integer
you are in a $math$ discord server, how dumb can you be
Hallows
@last folio it will be (y+2)**2 = x
^
@frank vine don't give out answers.
Alright but i included steps
You might wanna 'try' finding integral roots, for the leading coefficient is 1, check the integral factors of -192.
when applying transformations to quadratic functions why does addition shift x coordinates to the left, but when applied to y coordinates they get shifted up?
specifically why do x coordinates get shifted left and not right
the unknown zero would be 3 - 3i since the polynomial has only real coefficients and according to the complex conjugate theorem: if a polynomial with real coefficients has a complex zero, the conjugate of the complex zero will also be a zero of the polynomial. after all, if a polynomial has real coefficients and complex zero, we need the conjugate of the zero to cancel out the terms with imaginary coefficients.
so the final answer would be (x + 5)²(x + 3 + 3i)(x + 3 - 3i)
if the input is added by 1 (turning x² to (x + 1)²), the graph shifts to the left since the inputs will be added by 1 before being evaluated
so if you input 1 you will get (1 + 1)² = (2)² = 4. the one becomes a 2 before being evaluated.
if you input 2 you will get (2 + 1)² = (3)² = 9. the 2 becomes a 3 before being evaluated.
basically the inputs are being "pushed" further by one
this applies to all functions and not just quadratic functions, i.e. all functions shift to the left if you add to the input before evaluating
feel free to point out any mistakes
Oh so it's like you reach the y coordinate sooner than you would have, so the graph shifts left?
yeah
is there any proof of that theorem
In mathematics, the complex conjugate root theorem states that if P is a polynomial in one variable with real coefficients, and a + bi is a root of P with a and b real numbers, then its complex conjugate a − bi is also a root of P.It follows from this (and the fundamental theorem of algebra) that, if the degree of a real polynomial is odd, it mu...
kk thx
here's a "proof" that is more easier to understand:
wiki one was better
Are there any good videos explaining how this step works
5-11 = -6
oh lol
lmao
Can anyone help me understand this? I know how to do this process in reverse
But this is more intimidating and complex it seems
do you know how many minutes make a degree? @thorn valley
I'm not sure. I just know that in a D M' S'' format M is x/60 and S is x/3600. So D is probably just x/1 right?
ok then let's forget about angle
do you know how many minutes of time there are in an hour
60
right
the relationship between hours, minutes of time and seconds of time is the exact same as between degrees, minutes of arc and seconds of arc.
1 degree = 60 arc-minutes and 1 arc-minute = 60 arc-seconds
this should give you enough info to convert 0.7° into arc-minutes.
That would just be 0.7 * 60 correct?
yes
Okay I understand you this far
So what would I do for seconds? Nothing...?
yay!
I got it!
Thank you Ann!
hey can someone help with a question?
i got -2x-y^2 cos(xy^2)/ 2xy cos (xy^2)
but im not sure if its correct
do you have a pic of your work
its hard to read your result as it doesn't feel like you have parentheses where appropriate
https://www.khanacademy.org/math/precalculus would this be enough before ap calc?
The Precalculus course covers complex numbers; composite functions; trigonometric functions; vectors; matrices; conic sections; and probability and combinatorics. It also has two optional units on series and limits and continuity. Khan Academy's Precalculus course is built to deliver a comprehensive, illuminating, engaging, and Common Core align...
Probably yeah
so Im trying to learn precalc since I am trying to take ap calc ab after this summer. I dont thnk i can finish this khan academy actually within a month. Do you have any good idea I can use to learn all precalc stuff I need?
For calculus I would want to know a lot of trig, exponential properties, logarithmic properties, systems of equations, and basic algebra rules
ye
Keeping it real, I completely skipped precalc and did fine in calc BC
I’d just review parametric equations, conics, and polar coordinates (but I think some of this is bc, don’t remember)
That’s all you really need to know from pre-calc assuming you are strong in algebra (which you should definitely brush up in). Definitely some trig as in double angle formulas, thinking in terms of rad, sum and difference of angle formulas, but I learned that in alg 2 but I know some learn that in pre-calc
^ good advice as well
that’s calc? No?
no i got the answer the people in calc helped my thanks tho
starting calculus in grade 10 for gcses should i go to precalc or calc?
have you done pre calc before?
not sure really
the chapter im doing in differentiation 1 and 2 but if i look it up calc comes is as one of the top results
No it says “Horizontally” not vertically.
so -2(x)^1/2?
No, read my previous reply. Also play around with this https://www.desmos.com/calculator and read this https://www.mathsisfun.com/sets/function-transformations.html.
Thank you
Yeah
Looking for a definition, or for examples, or for the word "smooth"?
polynomials would be one set of examples
e^x
That is a polynomial 😀
e^x is not a polynomial
I have to start using these emojis stuff properly.
Yeah e^x exponential not polynomial
Can someone please explain me the reason of the intersection points of a function with its inverse its found simply equalating it to X. Example, f(x)=ax²+bx+C intersection points with its inverse can be discovered equalating ax²+bx+c=x and solving it. I am seeking to know a possible mathematical explanation for that.
functions and its inverse are symmetrical across y=x
That doesn't find all intersections between (the graph of) a function and its inverse, though.
For example, f(x) = (pi/4 - 1)x - arctan(x) is bijective R->R, and intersects its inverse at (-1,1) and (0,0) and (1,-1); only one of these intersections satisfy f(x)=x.
The intersections with the inverse all correspond to solutions of f(f(x))=x, though.
Yeah but what is the logic behind equalating the function to its varible to find inverse points?
Can you give me an example, im not sure what you mean
If (x,y) is a point on both the graph of f and the graph of f^-1, then one of those means y=f(x) and the other means x=f(y). Insert the former in the latter, and you get x=f(y)=f(f(x)).
This is in particular true if x=f(x), so solving that equation gives you some of the points of intersection.
can someone give me insight on how this is wrong?
i thought it would be correct but i believe im missing something
The denominator cannot be 0
Oh
So will it be what I wrote + excluding - 8 and 8?
Wait not 8
Oh
-25 and 25 then
Okay that makes sense
Thx got it
Let f^-1 (x) be y, then swap y and x
Solve from there in the form of y=
A⊆B (read: A is a subset of B) is saying that every element x in A is also an element in B
A⊂B (read: A is a proper subset of B) is saying that every element x in A is also an element in B, however there is at least 1 element in B that's not in A
in some places ⊂ is used for subset and ⊊ for proper subset so just keep an eye out for context
i like to use ⊆ and ⊊ to avoid ambiguity
would it be good idea to learn and review through the calculus readyness test? I just finished algebra 2 and now thinking of skipping precalc and go into ap calc ab
@prime moat I’d recommend you ensure your knowledge of trigonometric, logarithmic, exponential, and rational functions first
And ensure memorization of the unit circle
most of the other stuff in precalc doesn’t pertain to calc
i already know full unit circle yay
@unborn cloak do you know this
Yea I do
pls tell
It is the minimum between the two elements
It's the the minimum of the function x or x² so suppose at x=1/2 x²<x so we'll take x². Continue like this
i see at [-infinity,0] and [1,infinity] we will take x
and at 0<=x<=1 we will take x^2
thanks
Yep
ive went through ecponential laws, simplifying rationals, polynomial division
how far am i for ap calc preparation
Hey guys sorry to bother you studying for my exam at the moment and these logarithms equations are brutalizing me. Would appreciate some help.
Pre caluclator
hm?
I need help
hey guys. I’m a new 9th grader and I need help learning calc, dm me.
Just ask questions in #calculus
Helllo
does a reciprocal function need to have a numerator of 1?
What is a "reciprocal function"?
The reciprocal function is the one that maps x to 1/x for every x.
Eren Yeager
how can you simplify the logarithm in the left hand of the equation?
Ty
So graphs can intersect with asymptotes? Or only horizontal asymptotes?
And can they fully cross an asymptote if they do intersect?
And if horizontal and slant asymptotes can be crossed, what are they actually there for?
As far as I'm aware, a graph can't intersect its own asymptotes, that's the entire point - the function approaches the asymptote, but never crosses it after a finite distance.
As far as I'm aware, a graph can't intersect its own asymptotes, that's the entire point - the function approaches the asymptote, but never crosses it after a finite distance.
no
misconception
for example take y=sin(x)/x
that has a horizonal asymptote of y=0
but crosses the that infinitely many times
So I'm guessing a horizontal or slant asymptote that gets crossed implies that the graph is discontinuous and there is another section that never crosses it?
Or is that not true?
no
stuff like horizontal and slant asymtotes describe end behaviour
and by themselves don't say much about anything else
oh interesting, I'm guessing their use will make more sense to me once I'm deeper into calc
The top photo contains the details, the bottom are the individual questions
The pencil stuff is from me, and might be incorrect
<@&286206848099549185>
you cant find imaginary roots in the real cartesian plane
Please help me q 7 and 8 <@&286206848099549185>
It looks easier to start by writing an equation for f(x)-10, which seems to have three real roots on nice grid points.
Why when somebody asks for the x intercept, you don't need to specify which axis your answer's on, but if somebody asks for the vertical asymptote, you need to specify with x= before the value?
Is the second example not implicit like the first example?
for example:
The x-intercept is the “number” on the x-axis which the curve passes through
The asymptote is the “line” which the curve approaches
Therefore to represent that line you need to use an equation for that line, say x=7
oh that makes sense, ty
Is there a reason why this specifically says third row and not quotient? And is this true for normal polynomial division as well?
Not for normal. Says synthetic for a reason
It wouldn't end up being the same coefficients, constant, and remainder with the same signs?
hey can someone help me with a question i have?
#❓how-to-get-help or just post it here
for sure
i dont understand how i could rewrite it
and the textbook also doesnt really help me
could anyone help me with these couple of questions?
i want to be able to understand the concept better
yes
this is currently for the first box that you left blank
yea log4(x-3) was not the answer unfortunately :(
I know
oh what
when yousaid yes i thought you meant that was the answer
well i got that one wrong, but ill try to learn it still
b= log4(x-3)
the yes was to the b representing log_4(x-3) in the equation
i c
but what I wanted was to forget about logs for a sec
and if you were just given
a = b + c
what would you answer if you were asked for
b
b
you should have said that to begin wiht
unless you mean like
yea i know that much
i didnt know you want to forget about the log
so would b = 4?
okay forget everything else for a se
if i am just given a = b+c on a piece of paper
and you ask what b is
i would say that b is b
forget about everything (in the question)
don't forget about basic algebra
don't forget about a=b+c
clearly they don't want you to its say stuff like x = x
I don't want you to its say stuff like x = x
use desmos and get the graphing calculator
idk what to do for the next steps it is so hard smh
stuff is mad helpful
oh you probably have ot factor -x^2+2x+3
factor that, and you get your 2 x intercepts
and then try to find the vertex wiht a formula (i forgot which one) and you can plot it that way
perhaps I might have to make it extremely clear
starting with a=b+c
if you were asked to solve for b
(as implied by asking b = ?)
what would you do?
I did
I found the vertex I just don’t know how to plot the four points
lmao i see what you mean, b= a-c
to get additional points, choose some values of x, plug into the equation to get the respective y values to get your points
ohhhhh
when you do b=? , i am assuming you are asking me to fill in b, instead of make it so that the equation a=b+c is in terms of b
it was pretty clear I wanted you to isolate b I'm the equation I gave you
if I wanted you to respond with b=b
I wouldn't have even mentioned the equation a = b + c
okay sorry for being dumb ig and not being able to read it the way you read it
oh well it is what it is, ill just take the L
My first parabola done without a calculator 💪💪💪
Help pls
@fleet forge do you still need help with this
Can someone help me with this please
,rccw
I’m not sure if this will help but here is my working out, I’m not sure what to do past here/if I did anything wrong
P(x)-(4-x) is divisible by 1-x²
Since 1-x²=(1+x)(1-x)
P(x) - (4-x) is divisible by 1+x
Hi yes please!
ok
can you describe in your own words what it means for a sequence to be an arithmetic sequence?
Basically a set of numbers that are in order and it’s made out of terms and is a list of numbers where the difference or distance between consecutive terms is a constant
...well there is a kernel of truth in that, i'll give you that.
it's a sequence in which the difference between consecutive terms is always the same
and this difference is called, fittingly, the common difference.
Ohhh
now, you have the sequence that begins -38, -47, -56, -65, ...
what is its common difference?
-9
correct
now you know the first term (among others) and you know the common difference
do you understand now how to write down an expression for the general term?
careful there
(n-1)-9 looks like you are subtracting 9 from (n-1), which is not what the formula you quoted says
you need to multiply (n-1) by -9
so you would want -38 - 9(n-1)
Right
or, if you want to be absolutely 100% adherent to how the formula is written, -38 + (n-1)(-9) or something
but that's kind of silly
Okie thank you
Just to confirm it would end of being tn= -9n -29 as the answer?
Thank you for the help!
@willow bear out of curiosity what was the process of getting honorable?
that is classified information.
How do you show that there is only one rational zero
well you've found one
now you can factor it out and show that the quadratic that remains doesn't have any rational zeros
Thanks
Sorry for the multiple questions but I’m not sure how to approach this
you can rewrite P(x) by completing the square
What do you do after that?
who said c = 4?
well you could modify what you have here to not be wrong
$x^4 - 4x^2 + c = x^4 - 4x^2 + 4 + (c-4) = (x^2 - 2)^2 + (c-4)$
Ann
the equation P(x)=0 thus rewrites as (x^2 - 2)^2 = 4-c
thus if 4 - c < 0 then there are no real solutions
and if 4 - c ≥ 0 then there is at least one
Ohh that makes sense, thank you 🙏
I need some explaining on these problems
can you pls tell me where should i post questions related to set theory
don't ping random ppl out of the blue like that
but #discrete-math seems to be the place you're looking for
First simplify it, which will give you ${1+(1/x^4)}$
dimi
Then what
Apply it linearly, changing $\int1/x^4dx+\int1dx$
dimi
Solve it by removing the 1dx, so we can solve 1/x4 on its own: $\int\frac{1}{x^4}dx$
dimi
dimi
Now sub in the integrals: $x-\frac{1}{3x^3}$
dimi
Done! The answer is $x-\frac{1}{3x^3}+C$
dimi
I think
Can you please write it on a paper
I didn't get the whole idea
If it is possible then please write it on paper
I'm sorry, I don't have any to hand.
When I get some I'll show you, but I'd rely on one of the other, more experienced members, who actually know how to use LaTeX
hello
wait what
this isn't right
Am I doing the wrong method?
square root of (1 + 1/x^4) is not 1 + 1/x^4 ?
Is it possible in this case
Coz we have square root all over equation
How can we split integration just inside the square root?
SHIT I FORGOT TO WRITE THE ROOTS
Sorry I'm still getting to grips with LaTeX
That's what I am saying
can you post the full problem
likely you are not supposed to evaluate the integral
Sorry about this, I was being stupid
no I mean like the question text too
I just need to know how to solve this integration that's it
It's ok brother
can you like post the full page maybe
I don't have that book anymore 😑😑
$\sqrt{\frac{x^4 + 1}{x^4}}$
MathOnNapkins
And maybe trig substitute / integrate by parts 🤔
Find the value of L
no there's no way
are you allowed a calculator
i am trying trig
Yes but I have to do it on paper
it doesn't work
wolframalpha gives it in terms of a hypergeometric function
I don't think there is any way to evaluate this integral with the tools you have
besides just plugging it into the calculator

Why are integrals in the precalc section
I have no idea
But they shouldn’t be there
yes
hey guys im gonna take precalc next school year and i was wondering what math i should brush up on to help me have an easier time
i feel like most of my mistakes are because i am not careful enough
Trig
Algebra I, Algebra II, Trigonometry
I honestly can't even remember what I specifically learned that I hadn't seen before in Precalc. Probably Trig. Otherwise it seemed like a lot of drilling preparation for Calculus
It is preparation
Preparing for the preparation is Algebra and Geometry
in terms of parametrics, when would I use the first y = formula and when would I use the second y = formula?
nvm i figured the first one is in feet/sec and the other is meter/sec
if you're trying to memorize both of these formulas then you're setting yourself up for overcomplication and failure
if anything the middle term should be $-\frac{1}{2}gt^2$, where $g$ is gravitational acceleration
Ann
when is sqrt(x^2 - 64) = 15?
Oh i am such an idiot
i mistook -13 and 13 with -17 and 17
that makes sense
On another note, how could someone go about finding specific functions in composite functions?
To find f(x) in something such as f(g(x))
I always used intuition to find them but it doesn't seem very efficient, is there a more reasonable approach?
if all you're given is f(g(x)) then there cannot be a "more reasonable approach"
because compositional factorizations like this are not uniquely defined
Well usually it is the other function as well
For example "Find g(x) given f(g(x)) and f(x)"
Or for f(x)
i mean in that case if f happens to be invertible then g is recoverable as f^-1 composed with f o g
Oh!
I never thought about that
Canceling the functions by taking their inverse
Yeah that does seem very reasonable thank you
sorry i have a question
lim x -> 0, sinx/x = ?
without consulting derivatives
are you allowed to use the squeeze theorem
do you mean "does it work"?
yeah sorry
prove $\cos(x) \leq \frac{\sin(x)}{x} \leq 1$ for $x$ sufficiently close to zero. that'll get you a proof that $\lim_{x \to 0} \frac{\sin(x)}{x} = 1$.
Ann
Unrelated but curious, but do you write all of that yourself for the @obsidian monolith bot to process it?
yes
ah i see, seems complicated
i am curious now, though. How did we build up into the cos(x) leq sin(x)/x leq 1 to begin with?
I would imagine using sandwich theorem you would have something along the lines of -1/x and 1/x on both ends
it isn't once you've had like 5 years of experience with it
i guess i graphed it somewhat in my mind so it does make sense i suppose, but trying to find a way to derive them mathematically
Fair enough
lim x -> ∞, sinx/x
is there any alternative solution possible rather than using sandwich theorem
well you could expand sin(x) into its taylor series whence the result would follow immediately, but that ultimately relies on derivatives so i imagine it wouldn't fly
i understand thank you
i can't proof cosx < sinx/x < 1
$\cos(x) \leq \frac{\sin(x)}{x} \leq 1$
theman
i mean this
can you prove that sin(x) <= x for positive x?
and that tan(x) >= x?
i don't know if you have a formal definition of sin and cos on which you are supposed to base your proof.
@astral bobcat
i can't
the mean value theorem?
...
mean value theorem relies on derivatives so that is a no-go.
tell me what your class's definition of sin(x) is.
the opposite side of the angle divided by the hyptenuse in a right triangle
well not exactly
...
then show me the EXACT definition for god's sake
how the fuck do you expect to produce any sort of proof if you don't even have any definitions on which to base it???
no definition no proof
simple as that
maybe look through your notes or ask a classmate
how about i get the unit circle
ah well NOW we're talking.
get a triangle with the field cosx.sinx/2
with area cos(x)sin(x)/2.
and a circle slice with pi.1^2.x/2pi
You mean a sector?
and a bigger triangle with the area tanx/2
and compare the areas
you know what i get it
can i ask about diffrentiation here?
How many turning points would a function $y = \frac{f(x)}{g(x)}$ have if the power of both f(x) and g(x) is two and the discriminant of f(x) < 0?
∫Inheritanc-e ♦
do you mean the degree of f and of g are both 2
@wise spoke i believe that this info alone is insufficient to determine the number of turning points
there exist rational functions satisfying your requirements with 2, 1 and even with 0 turning points
Take it to calculus
Oh
already gotem
gracias por te ayuda
