#precalculus
1 messages · Page 238 of 1
imagine drawing a vertical line at x =1
then your set is the right hand side of that
not including the line
yeah sorry
what do you mean by discrete
not continuous
integers in this case
ive got to admit im a tad confused by this set
no idea how to draw it then
i mean
since the second part of the pair is a real number + an integer
thas just another real number
so i'm good?
whats the question?
if x is 0
for
{(x, x+ y) : x ∈ R, y ∈ Z}
I drew this
@viscid thistle
you have all the integers on the y axis
if x is 0.5
all the 0.5 offset integers on the line x = 0.5
okay i think i got it
i belive it's a striation of lines with slope of -1
each offset on their y intercept by integer values
could you please draw it
yes lemme do it quickly
this is what drawing with a mouse gets you XD
this isnt a shaded area
the lines that arent the axes are part of the set
how have you arrived at this conclusion
i belive it's a striation of lines with slope of -1
@smoky pagoda
checking certain cases of x
havent proved it or anything though
but intuition gets me this
because on any line x
like vertical line x = a
you can plot points on it that belong to the set but these points will be separated by integer distances
additionally the value of x applies an original offset
since we have x+y
and this offset will be the same for integer values of x
which is why the 0s are at x = ...-5,-4,-3,-2,-1,0,1,2,3,4,5,....
and otherwise between these intervals the change in offset is continuous
makes sense
in the last two I have no idea what R^2 is supposed to mean.
51 {(x,y)∈R^2 : (y-x)(y+x) = 0}
here I would just do y^2-x^2 = 0
52. {(x,y)∈R^2 : (y-x^2)(y+x^2)=0}
not sure
R^2 is the real plane
think of it like a 2D R
similarly R^3 is the 3 dimensional real space
so it's the same as saying x belongs to R and y belongs to R
haven't i been drawing R on a 2d sheet of paper
and for the last one you would do y^2 - x^4 = 0
yes youve been using R^2 up till now anyways
but it told me to use R?
it's just your regular plane
no but your sets as subsets of R^2 by convention
the sets themselves arent always R^2 though
it's just R^2 is easily represented by a cartesian plane
so you're saying that (x,y) belong to R^2
which must mean the resulting set is at least a subset of R^2
If you know what a cartesian product is, R^2 is just shorthand for RXR
could you please draw both - show me the difference between them?
{(x,y) : x, y ∈ R, x^2 +y^2 = 1}
{(x,y) : x, y ∈ R^2, x^2 +y^2 = 1}
cause from what you're saying i get that there's no difference in drawing
k=okay so your second set isnt exactly correct
elements of R^2 must be of a form (x,y) where x,y belong to R
x and y are real numbers
but the tuple (x,y) is an element of R^2
you cant say x belongs to R^2
or x would have to be its own tuple
R is the set of all real numbers
what about
{(x,y) : (x, y) ∈ R, x^2 +y^2 = 1}
{(x,y) : (x, y) ∈ R^2, x^2 +y^2 = 1}
then
guessed it
because you say that a tuple belongs to R
so when using tuples, I say that they ∈ to R^2, otherwise to R, yeah?
yes
ok I get it
ok thanks
note this power notation can be applied to any set
in general A^2 = AXA
where X is the cartesian product
have to go now, bye
alright bye
The set T = {0,{1, 2, 3}, 4, 5} also has four elements, namely, the three integers 0, 4
and 5 and the set {1, 2, 3}. Even though 2 ∈ {1, 2, 3}, the number 2 is not an element of
T; that is, 2 ∈/ T.
why not? if A = {1,2,3}, A ∈ T, 2 ∈ A, then does it not logically follow that 2 ∈ T ?
no
since A is considered as single element here
ur statement would be trou if u were talking about subsets
but not sets as elements
thanks
how come
ac + adi + bci + bdi^2 = (ac − bd) + (ad + bc)i
isn't
(ad + bc)i = adi + bci
and that would mean that
(ac − bd) = ac +bdi^2
?
It is true
how is it derived
Are you asking how ac-bd=ac+bdi^2?
yes
ac-bd =ac+bd*(-1)=ac+bd*(i^2) since i^2 is defined to be -1
oh makes sense, thanks
what about
Let S = {−2, −1, 0, 1, 2, 3}. Describe each of the following sets as {x ∈ S : p(x)}, where p(x) is some
condition on x.
D = {−2, 2, 3}.
i don't see a pattern here
p(x) : |x| > 1
it wouldn't include -2 then, I think?
|x| is the absolute value of x
oh right
😄
also wouldn't 'your' set in full be written as
'{x ∈ S : p(x), |x| >1}'?
yeah thanks
is there a method for questions like this?
The set E = {..., −4, −2, 0, 2, 4,...} of even integers can be described by means of a defining condition
by E = {y = 2x : x ∈ Z}={2x : x ∈ Z}. Describe the following sets in a similar manner.
they are really time-consuming for me
no there is no method
thanks
how do I solve this
x^2 − (2 + √2)x + 2√2 = 0?
I don't know how to combine -2x with -sqrt(2)x
i guess
D = {x ∈ Q : x^2 − (2 + √2)x + 2√2 = 0}.
describe the set D in another manner
what is meant by this? like do
{x^2 − (2 + √2)x + 2√2 = 0 : x ∈ Q}
instead?
is it possible to describe it any other way besides these two?
List the elements of the set i.e. roots of the quadratic equation.
the second is bad
but in this form
solve the equation
2, sqrt(2)
{2, sqrt(2)}
so are there only 3 ways?
two ways
{x^2 − (2 + √2)x + 2√2 = 0 : x ∈ Q}
is incorrect, yes?
not exactly incorrect, but yeah
ok thanks
You're welcome ^^
For A = {2, 3, 5, 7, 8, 10, 13}, let
B = {x ∈ A : x = y + z, where y,z ∈ A} and C = {r ∈ B : r + s ∈ B for some s ∈ B}.
Determine C.
what is meant by determine C? like do
C = {r ∈ B : r + y+z ∈ B, where y,z ∈ A} ?
B = {5, 7, 8, 10, 13}
C = {10, 13}
why is C= {10}, what about 13? 5+8 = 13
Oops, my bad
thanks for all your help
for this problem i get undefined because i can’t do arccos when the value i plug in is less than -1
so this problem doesn’t even have an answer am i making a mistake somewhere
where are you getting sqrt(4),
Hello, I was wondering if someone would help me understand a classic interest rate problem. I couldn't follow their steps.
@junior sable increasing something by 5.75% is the same as taking your number, and adding 5.75% of that number
5.75% of something is that thing times 0.0575
so they just did that three times
gotcha ty @remote veldt
and specifically with interest, after your money increases, you now have more money that will increase
gotcha. it recurs
can I ask your help with this one? how do you quickly find the horizontal asymptote of this?
Do you just plug in values?
well a horizontal asymptote asks about behaviour as x gets really really big, either in the positive or negative direction
when x gets really really big in the positive direction, what happens to 2 * e^(x - 2) + 3?
I suppose it gets bigger. e is getting raised by a bigger and bigger number
yes! it blows up to infinity
so there's no horizontal asymptote that way
because a horizontal asymptote, sort of by definition, requires flattening out
what about the other direction? when x gets more and more negative?
It would get smaller and smaller. As it passes 2, it will start to look like a fraction, 1/e
yep! and then 1/(e^2) and then 1/(e^3). As the exponent gets bigger and bigger, the exponential term gets closer and closer to 0
2 * 0 is just 0
so as x gets closer and closer to -infinity, the function gets closer and closer to 0 + 3
which is just y = 3
you said that there's no horizontal asymptote, but isn't it y=3?
there's no horizontal asymptote in the positive direction
sorry, the "that way" meant "in the positive direction"
you need to check both
and yes, the horizontal asymptote is y = 3
but it's important to check both the positive and negative direction
sure. that's very helpful, thank you
because there might be more than one asymptote, or the asymptote may only exist on one "side"
for example, the inverse tangent function has two horizontal asymptotes, and the two are different in the positive and negative direction
In this example, how do I know that there isn't a vertical asymptote as well at x = 4?
well, the sort of cheating way is to say that f(4) exists
that's a little imprecise, but it is definitely the right idea
a vertical asymptote is that, as x gets closer and closer to the point, f(x) gets closer and closer to either positive or negative infinity
if f(x) is continuous and is defined at a point, there isn't an asymptote there
yes!
because think about it, an asymptote kinda keeps going up
(or down towards negative infinity)
There's a peak when it comes to vertical asymptotes, right? eventually you get over the hump and start coming down
no!! what makes it a vertical asymptote is that you keep going up
and at the peak it's undefined?
there is no peak
oh...oof.
consider f(x) = 1/x as x gets closer to 0
give me any real number k, and I can find a value of x so that 1/x > k
98? ok 1/(0.01) > 98
if you had picked 183423874823748237482374238 I could say that 1/(0.00000000000000000000000000000001) > 183423874823748237482374238
I can always find a number 'close to zero' (I'm putting that in quotes because it's imprecise but I think that any reasonable person would know what I mean) so that it gets arbitrarily large
that's what makes it a vertical asymptote
so a little more precisely, you know that e^(x - 2) + 3 doesn't have a vertical asymptote, since near any point, it's bounded
wtf is going on here holy 👀
wha?
horizontal asymptote, is when you have a very large negative/positive x value, in which the function approaches some constant value
I guess I still don't understand it. I mean in e^(x - 2) + 3 it does get progressively bigger and bigger, why isn't it an asymptote?
for your function g(x) = 2e^{x-2} + 3, it's obvious that for a very large positive number, it doesn't approach any constant value, it just keeps going up, but for a very large negative number, the e portion approaches a very VERY small value, almost negligible, thus resulting in a constant value of 3
there is a horizontal asymptote
okay that's helpful
@hard hornet yes, we established there is a horizontal asymptote
choose a very large negative x value
but I guess I still don't see why f(4) isn't an asymptote, is it just that the function doesn't approach a specific point there?
if you're still confused, take a look at this function instead, not sure if this'll help
,w graph y = e^x
asymptotes are values the function never reaches when you approach negative infinity or positive infinity
we talk about asymptotes in the context of VERY LARGE numbers, i.e infinity
buncho, what I'm replying to is
In this example, how do I know that there isn't a vertical asymptote as well at x = 4?
the answer is that f(x) is bounded near 4, or alternatively, that f(4) exists and f(x) is continuous
since for there to be a vertical asymptote, f(x) must be unbounded near a point
similar idea, except instead of x approaching infinity, it's more like y not being defined, and y blowing up to infinity as you get closer to x = 4
...and that is exactly what I said
if you're trying to figure out easy, simple tests for asymptotes, for horizontal asymptotes, choose a very large positive/negative value, and for vertical asymptotes, usually it's with functions with fractions, because that's how you get undefined values. Check the point in which it's undefined
@remote veldt are you a teacher? You have a real gift for encouragment.
I'm unsure if you're being sarcastic or not ;-;
Well it suits you!
I got another one for you if you're ready
?
it does get progressively bigger and bigger, why isn't it an asymptote?
an asymptote needs to be getting bigger without bound at a specific point
for e^x or any transformation thereof, for any point you pick, e^x is a finite number, and e^x is finite near that point
what makes it an asymptote is if it goes to +/- infinity at a point
not if it goes to +/-infinity as x goes to +/- infinity
and it's because there will be an x value which is undefined as it approaches it?
there is a vertical asymptote if there is an x value where the function goes to infinity as you get close to that x value
e^x has no such x value
so e^x has no vertical asymptotes
e^x has a horizontal asympote, since as x goes to negative infinity, y gets closer and closer to 3
okay, i think i get it now
awesome!
yeah. cool!
I got it.
Here's the one I'm stuck on now. I just don't understand the "Grammar" of logarithms.
does this mean that 4^(gx) = x+1?
I tried to plug in -1 for x and then I got confused
rearranging it into that form isn't going to be particularly helpful/meaningful; your simplifcation is a little bit wrong though.
I would hope that you got confused if you plugged in -1 for x, since the function is only defined for x > -1
how so?
Try graphing the parent function and then transforming it.
the (x+1) moves the graph left 1 I believe.
yeah. This is a series of transformations applied to log_4(x)
[which is really just ln(x) multiplied by a constant but whatever]
I think I need to understand graph transformations....i hate graph transformations....
And on the website I'm working with, they don't let you choose a log shape and then play with it
you have to plug in x and y coordinates
So you do need to make your way through the function algebraically
that's what I'm stuck on right now
I mean I have a final on wednesday that I can't use Desmos for
but to gain understanding
sure
When doing so don’t just make it give you the answer, try to understand the nature of the function you’re transforming. (e.g how it transforms based on the transformation.)
yeah^^ of course. But if you play with the sliders one at a time, you can get a lot of intuition
I agree.
just gotta play with it.

Does it ever seem impossible to try to map out the geometric and visual knowledge onto the mathematical, algebraic knowledge?
I can play with a map and go "Oooh, pretty shapes" but that's a whole different skill set than "How do these numbers work"?
And I'm not entirely sure I can keep both in my head at the same time.
I don’t know if I understand what you mean... like trying to retain geometric and algebraic intuition? or smthn
Well you can understand math visually, with graphs, or you can do it with pen and paper and logic.
I mean they go hand in hand, you just have to study their relationship.
it took me a month to understand why y = Mx + b somehow turned into a / or \ . I just had to ask why the formula did what it did...
I guess I’m not too good at e x p l a i n i n g stuff huh?
@junior sable make sure there's a method to how you play
you should be able to answer
- what does increasing this do geometrically
- what does it matter if this is positive or negative
- what does decreasing this do geometrically
for all the parameters
that’s much better ^^^ yes
ie start by playing
then start asking specific quetsions about what happens when you play
that’s a spectacular gif
@remote veldt I'm telling you, you're gonna be the next 3blue1brown
LMAO no way
Who is 3b1b
you gotta check him out. he's the bob ross of math
@viscid thistle https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw pick a topic go nuts
Yea just looked him up
Might just become one of my idols
alongside Khan and Gauss
I could have used someone like him in my life 10 years ago
Teaching math with patience and wonder
well maybe I can use him now
definitely. it's never too late. he covers topics way more advanced than what I'm ready for but maybe you'll find something your liking
he seems like a genius,
I will have to check him out
mathematics is the language that which we speak to the universe in.
thanks everybody for the help! sorry I got lost in desmos
@remote veldt I'm going to try to tackle it now algebraically now, any pointers? it looks like a real tangled mess
If i put 4 in for x I get 3 log 4 (4+1) -1...what order do I begin to evaluate such an expression?
leviosa:
yes
leviosa:
,w log_4(5)
leviosa:
how would you solve it if you didn't have access to a calculator?
solve what?
$3 \log_{4}(4+1)-1$
Jandro:
Generally you would just leave it as 3log_4(5)-1
i woiuldnt be able to give you the exact value, but i could give you some approximation
I don't know what my class is expecting of me
this is precalculus, they wont ask you to give the exact value
They give me that as g(x) and then say "graph it" no graphing calculator
when they say graph it
it's more like
understanding the general structure of it, and some important points
no they literally want me to graph it
if you gave me $g(x) = 3\log_{4}{x+1} - 1$, i would base it off parent function
You want to plug something in then.
yes
You can do a few things.
Cytis:
You can do the inverse of the function.
You'd then have to deal with a function of y rather than a function with x.
(Literally just turn your paper 90 degrees LOL.)
computer class. sure I'll turn the monitor 90 degrees
Or, you can plug in certain x's that will make it so that log_4(??) would turn out to be a constant number.
well, you'll still need to understand some form of the parent graph
if you understand your parent graph
then this question is trivial, it ends up being an easy transformation
.-.
I understand the parent graph, i just need some stable numbers to graph onto
and they won't let me get those without a calculator
@hard hornet Nah. Shitty classes like the ones I take asks you to make sure you have 5 dots plotted 🤡
still easy
Jandro, you following?
Anyways.
yeah, the parent function is right
okay, how do I do that without desmos

its obvious you have some points already from the log function
(1, 0)
(4, 1)
(16, 2)
(64, 3) etc etc
and there's a vertical asymptote
so there, boom, you got the structure of the graph already
do you know what the logarithm function is?
It's a measure of magnitude
give me the definition of the logarithm function in terms of exponents
a^b = c, log a c= b
yup
log_4(x)
means if you plug in powers of 4
you get the exponent
(4^0, 0)
(4^1, 1)
(4^2, 2)
(4^3, 3)
(4^4, 4)
etc
that's how you get the numbers
and to be clear, we're talking 4 as the a value for log, right?
okay I'm not 100% sure I get you but I'm starting to get there
ok
using the definition of logarithm u stated
come up with your own points
ping me when you feel like you've got it
well okay @hard hornet 16, 2 and 64 and 3
16 and 64 are the c values, 2 and 3 are the b values
are these coordinate points?
so ur parent function looks like this, right?
(16, 2)
(64, 3)
(x, y)
are on that line
its the graph of the function y = log_4(x)
please continue
now
let's start adding some components to it, and slowly build out way to the original function
we know what y = log_4(x) is, now try to figure out what happens with y = log_4(x-1)
hint: it's a shift of the graph
think it through, no answers for you
It's a move to the right, but only because I was playing with it on Desmos earlier in the night
👍
makes sense right?
since it's x-1 instead of x, you need to increase the value of x by 1 to maintain it
now, let's move on, this one is going to be a bit harder
now, try y = 3log_4(x-1)
hint: it's a shrinking of the graph
I thought it was an inflation of the graph. I thought the graph has higher values with a higher a value
leviosa:
Okay.
@hard hornet Your pfp cute.
yes you're right
its stretched upwards/downwards
ty ❤️
my mistake, good catch on that
now
the final part
y = 3log_4(x-1) + 1
i think that was the original querstion
-1
how does it shift?
down 1.
,w graph y = 3log_4(x-1) + 1
That silence basically means no.
no i mean you had the wrong function
it's -1, not plus 1
the coin flips in my favor!
well, you could reverse engineer
we know that the data points originalyl is
(4^0, 0)
(4^1, 1)
(4^2, 2)
(4^3, 3)
right?
right
in the first part, this gives us these new points
(4^0 + 1, 0)
(4^1 + 1, 1)
(4^2 + 1, 2)
(4^3 + 1, 3)
for the function f(x) = log_4(x-1)
agree?
here's where I get lost
the new y values, how did you get them?
wait
I mean the new x values I misread it
we went from a change of x to x-1 right?
right
to maintain the same y value
we have to negate it
by adding 1 to each x value
do it on apper
paper
and work the math out
yeah that type of motion I never understood
it's kind of realizing, oh shit the function needs an increase of 1 for the x value to maintain the same y value
so, just add 1 to each input, and keep the y value the same
basically
so it's gonna shift to the right
Oh wait wtf.
I thought your pfp was a bunny.
But it's a fucking bird bunny.
I take what I said previously back.
lmao
Ugly asf.
😦

ban this fool.



so far so good @junior sable
wait, i'm almost there
ping me when ur ready to move on
so you're saying that instead of a point being at (16,2) it's gonna be at (17,2)
@hard hornet
Are you graphing this on paper 
This man aboutta graph (65, 4) 
What a legend.
Oh wait.
(65, 5)
Mb.

y = log_4(x-1) is what we're doing rn
Oh wait.
are you okay?
i know
np
i have a -10 by 10 field on a computer screen. what points can I use?
yeah
like does it have to be THAT ACCURATE???
yeah!!!
i think they expect me to plug in answers that have e's in them
that's if you're dealing with natural logs
hoenstly at this point, just use a freakin calculator,
on a test, you can approximate as long as you label ur points
if it has to be super accurate, everyone is gonna fail anyways, especially with a log function, on a 10*10 screen
you can prolly graph like 2-3 points RELIABLY
more like 2
4^(3/2)?
(4^0, 0)
(4^1, 1)
are like the only two points you can reliably graph
cuz im assuming only integer points are allowed, anything fraction will give u trouble graphing
no fractions are okay
there's a field for that
you plug in the fractions and it'll plot it for you
this homework assignment is giving me a headache

ok i legit don't know how to do it anymore. graphing homeworks shouldnt be done this way, it's silly
i gave you a lot of integer points to work with, and showed you the math behind it
try your best, if there's still anything you need, i'll try
I appreciate your help.
Thank you. Logs are making sense to me now
do you own a parakeet?
no, want to tho
I hear they're hilarious birds
they r
i hope you get one
I gotta go to sleep. thanks for the help, internet denizen.
Good night!
heyo ... Prove, for any distinct, positive a and b, (ln(a) + ln(b))/2 cannot equal ln((a + b)/2)
strict concavity of ln
yep yep. Man I don't think I've ever outsmarted you in math.
can someone walk me through how to do this problem?
is ln and log one of those operations you have to do on both sides?
i would assume so
... of course
But also take into account to choose the base of ln in our benefit
I need you active for this ass-long problem
@junior sable
First consider taking ln on both sides
But also take into account to choose the base of ln in our benefit
why ln instead of log 10?
Yeah that's what i meant
Take into consideration the base
To our benefit
What would be the base for our benefit
Of log
Look at the bases of the equation
11 and 9
What would be the base for our benefit
Try again
I don't know. 11 and 9 don't share factors
Do you know why im saying this?
no i don't
$\log_a(a)=1$ this will happen here on this problem
Al𝟛dium:
So try again
One of them
Lets keep with 11
So log_11 on both sides
So that
$$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$\log_{11}(11^{x-9})=\log_{11}(9^{6x})$$
Al𝟛dium:
Everything fine until here?
Al𝟛dium:
Everything good?
well hypothetically sure, but we don't have a's in our equation
the what?
3^12x
so 2(6x)
$$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$\log_{11}(11^{x-9})=\log_{11}(9^{6x})$$ $$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$x-9=\log_{11}(3^{12x})$$
so 2(6x)
@junior sable no like 3^(12x) not 3^12x
Bc its ambiguous
?
Al𝟛dium:
haha ok
12x log 11 3
Yeah
$$11^{x-9}=9^{6x}$$ taking $\log{11}$ on both sides $$\log{11}(11^{x-9})=\log{11}(9^{6x})$$ $$11^{x-9}=9^{6x}$$ taking $\log{11}$ on both sides $$x-9=\log_{11}(3^{12x})$$ taking 12x out $$x-9=12x\log_{11}(3)$$
Al𝟛dium:
i'm writing it down as we speak
So move the x term/s at one side and non-x term/s at the other
Yep
We are really close
$$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$\log_{11}(11^{x-9})=\log_{11}(9^{6x})$$ $$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$x-9=\log_{11}(3^{12x})$$ taking 12x out $$x-9=12x\log_{11}(3)$$ moving terms $$x-12x\log_{11}(3)=9$$
Al𝟛dium:
Well yeah fair
Now factor out x and isolate x and that's it :)
As it is the final step let me write it down
$$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$\log_{11}(11^{x-9})=\log_{11}(9^{6x})$$ $$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$x-9=\log_{11}(3^{12x})$$ taking 12x out $$x-9=12x\log_{11}(3)$$ moving terms $$x-12x\log_{11}(3)=9$$ factor out x $$x(1-12\log_{11}(3))=9$$ finally $$x=\frac{9}{1-12\log_{11}(3)}≈-2$$
@junior sable
Al𝟛dium:
Welp you did different stuff on the very few last steps
Post a better pic
Also on the last step you didn't isolated x correctly
Also on the last step you didn't isolated x correctly
.
Pretty basic algebra
$a=x(b)$ isolate x is $x=\frac{a}{b}$
Al𝟛dium:
Al𝟛dium:
yes that's what I have
Al𝟛dium:
Pretty darn basic algebra
Apparently I'm not getting you.
oh i see
Post it
Yep correct.
$$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$\log_{11}(11^{x-9})=\log_{11}(9^{6x})$$ $$11^{x-9}=9^{6x}$$ taking $\log_{11}$ on both sides $$x-9=\log_{11}(3^{12x})$$ taking 12x out $$x-9=12x\log_{11}(3)$$ moving terms $$x-12x\log_{11}(3)=9$$ factor out x $$x(1-12\log_{11}(3))=9$$ finally $$x=\frac{9}{1-12\log_{11}(3)}≈-2$$
Al𝟛dium:
We got the same
What the hell is that?
Just type it onto the calculator and you'll get ≈-2
End of the problem
@junior sable ?????
Can you write instead of posting pics with no context at all
I'm asking if the answer if we got is the same as 9log11/(log11-6log9) which is the answer i'm supposed to get
,w (9log(11))/(log(11)-6log(9))
Yep its the same
Np!
I'm trying my best. try not to be angry at people who are trying their best.
You could have said "hold on" or whatever but if i see you inactive i lose my patience
oh it said that?
I'm new to discord
I was here the whole time
maybe I didn't move the mouse enough
And i said before that i was writing the latex for you to be focused, not writing it on your paper
Like being participative
And i'm taking notes, what's wrong with that?
Again. I was writing latex for you to be focused thats it
So the "notes" could be taken at the end
it's not easy doing this over discord. I had no idea you were angry. if this were irl it'd be totally different.
So that the attention goes to the conversation and not half-brain writing half-listening which is less efficient.
even voice chat would have been easier
Nah i wouldn't be able to do so
If i could i would have done it
Just don't worry, lets keep this channel open
See ya and good luck in the future @junior sable
ty @viscid thistle

how do u change this polar equation to rectangular coordinates
what do i change the x^2 to?
nvm i got it
Im trying to find the formula for this problem and I got 32,500 * 0.05^x
but when I try to plugin in 12 to get the value of it, it comes out wrong, help would be appreciated
The general formula for this is $$\text{depreciation}=G(1-\frac{r}{100})^n$$ where G is the initial value, r the rate and n the years
Al𝟛dium:
Try plugging the values of G, r and n as you have them again with the formula above and you should have it. @alpine basin
thanks
@viscid thistle Do you know how I'd match these functions? the differences seems so subtle and my teacher's video doesnt explain it well
ok
@viscid thistle let me with him
Pog.
Okay.
I was just gonna say, that you could definitely start by substituting x with 0.
Then everything else is easy claps.
lmao
You should know that $$f(x)=a(b)^x$$ is an exponential function. Consider the fact that a will decide the y intercept of the function as when a function meets the y axis, x=0. So basically $$f(0)=a(b)^0$$ and you should know that $b^0=1$ so we have $$f(0)=a$$ so from there we get that the a value on the function will act always as the y-intercept. (Notice that some functions have a=2 and a=4, look at the y-intercept to differentiate some). Now for the b meaning, the b will decide if the function decreases or increases. If: $$f(x)=a(b)^x, b>1$$ we know that the function will increase bc of the $b>1$ and viceversa we have $$f(x)=a(b)^x, b<1$$ we know that the function is decreasing. The last tip to differ these functions will depend on the b value, where i will explain through an example: Take 2 functions, $$f(x)=3(1.4)^x\ g(x)=3(3.2)^x$$ now notice that their a values are equivalent so, we can differentiate them by looking at the b value. On f(x): b=1.4 and on g(x):b=3.2 So what we will expect to watch on their representation is that f(x) will be way less curvy than g(x). As when the b value comes closer to smaller values, the curve will be smaller than when b is greater.
@alpine basin
Al𝟛dium:
Read the whole thing there is one more tip you are missing
,w graph 3*1.01^x
Look
The larger the b is, the faster the slope "goes up" as you go along the x axis.
yeah the way the line is flipped or not right?
,w graph y=3*4^x
yeah the way the line is flipped or not right?
@alpine basin decreasing or increasing as well matters
Notice how both functions have different b values and the way the curve differs
ye
Right
So any doubt?
The larger the b is, the faster the slope "goes up" as you go along the x axis.
@viscid thistle yeah that may be a better way of expressing it
@alpine basin all good?
Let's compare two cases.
$$y=(0.5)^x$$
and
$$y=(2)^x$$
$$ $$
In the first case, as x goes bigger, you eventually get: $\$
$\frac{1}{2} \cdot \frac{1}{2} = \frac{1}{4}$ for when x=2 $\$
$\frac{1}{2} \cdot \frac{1}{2} \cdot \frac{1}{2} = \frac{1}{8}$ for when x=3. $\$
$$ $$
In the 2nd case, as x goes bigger you eventually get:$\$
$2 \cdot 2 = 4$ for when $x=2 \$
$2 \cdot 2 \cdot 2$ for when $x=3 \$
$$ $$
With this, you can conclude that in the function of: $\$
$$y=(b)^x \$$
When $0<b<1$, the y value decreases for when the x value increases. $\$
When $b>1$, the y value increases when the x value increases $\$
leviosa:
Damn this is shit notation.
Whatever.
It got solved already lol
Yeah whatever.

:)
Np! @alpine basin





what is the name of the time speed and distance chat?
How would I show the horizontal asymptotes for these?
Just draw it
Use your big brain knowledge on translations.
And then use common sense.
yeah for 26 for example I graphed the line
yteah its -3 right
Yeah.
and 25 is 1
$y=a(b)^x+h \ \text{h is your horizontal asymptote}$
leviosa:
"sketch the graph"
Then it's +0.
hmm mk
a(b)^x+0
Would anyone be able to help explain a function decomposition problem for me
Post it
oops thats wrong
Given the composition h(x)=f(g(x))
If h(x)=(x+5)^8 and f(x)=x^8 find the function g(x).
Well so
A little bit of logic can be used here
We have $h(x)=(x+5)⁸$ and $f(x)=x⁸$
Al𝟛dium:
And we know that h(x) is f(g(x))
yeah
So
$f(g(x))=(g(x))⁸$
Hold on a sec
thank you
Al𝟛dium:
Now
And we also know that h(x) is basically f(g(x))
From logic reasoning, we have from the question that $f(x)=x⁸$ so let's plug g(x) on the function f(x) so that $$f(x)=x⁸$$ to $$f(g(x))=(g(x))⁸$$ And we also know that $h(x)=f(g(x))$ THEN as we are given that $$f(g(x))=(x+5)⁸$$ we can form this $$\begin{cases}f(g(x))=(x+5)⁸\ f(g(x))=(g(x))⁸ \end{cases}$$ to solve the system.
@viscid thistle
I'm trying to understand
Okok
the answer ends up being 5+x btw
Yep
Read it carefully
The very first line has little context hold on
Al𝟛dium:
i think i understand
Awesome
thanks so much
So we are basically done
yeah
so when you put the (g(x))^8
Yes
why isn't it (g(x))x^8
We put g(x) not (g(x))⁸
Wait where
Which line?
nvm i understand
thanks a lot
Good
Np!
x = 11
f(x) ~ 3x
g(x) ~ 9x
point f(g(x)) is a point of line (D)
determine the equation of line (D
please can.you help me
what q?
theres no line q
also there is no sketch
if thats what you asked for
i corrected value of x in the exercise
what q?
@lofty prism question
Post a pic of it
Im pretty sure you are missing stuff
what
post a picture of the question
Do it
why can't you take a picture 
but if you really can't, write out the exact wording of the question, and don't leave anything out
a = 5
f(x) = 3x
g(x) = 8x
(D) is perpendicular to (Cg)
f(g(a)) is a point of (D)
determine equation of (D)
i really hope i didnt miss something
i know how to do this f(g(a)) = f(a) * g(a) = f(5) * g(5) = 5/3 * 5/8 = 25/24
but idk what to do next lol
i think i need to use (D) perpendicular to (Cg)
but idk what to do with it
If you can't post a picture of it, i won't help. It looks really messy as you stated and very lacky of information.
I would also note that f(g(a)) is not the same thing as f(a) * g(a)
i am really sorry i will try to rewrite it and see if i missed something like really im sorry for wasting your time
I would also note that f(g(a)) is not the same thing as f(a) * g(a)
@remote veldt oh okay
Let a = 5
f(x) = 3x
g(x) = 8x + 4 and (C_g) its graphic representation.
(D) is a line of equation y = px + q with p and q real numbers.
Statements:
(D) is perpendicular to (C_g)
M(a;f(g(a))) is a point of line (D)
Task:
Find the values of both p and q.
is this okay now.i verified everything i think its complete?
so
is f(g(a)) equal to
f(g)*g(a) or something f(a)/g(a)
no, f(g(a)) is just f(g(a)). there's no multiplication or division
if g(a) = 3, then f(g(a)) = f(3). If g(a) = 12, then f(g(a)) = 12
how do you calxulate it
f(g(a)) means "take the number g(a) and use it as an input for the function f"
g is a function, g(a) is evaluating that function at a specific point a
... either way it's a real number
f(g(a)) takes the output of g(a) and uses it as an input for f
i am not sure you are correct we will wait for someone else to tell
He is correct. I tell
f(x) = 3x
g(x) = 8x + 4
f(g(2)) = f(8(2) + 4)
= f(20)
I am absolutely correct lol you have serious misconceptions about what functions are
In mathematics, function composition is an operation that takes two functions f and g and produces a function h such that h(x) = g(f(x)). In this operation, the function g is applied to the result of applying the function f to x. That is, the functions f : X → Y and g : Y → Z ...
oh
a function g(x) takes x as it's input and whatever the function does to it, it spits one output g(x)
that output can then be used as an input to f(x)
you give functions a number they give you another. and this another number cant be inputed in another function thats what i know it belongs to the "output class" so it cant be input
there is no such thing as an "output class"
just to illustrate
I will ask you a question
a function g(x) takes
xas it's input and whatever the function does to it, it spits one outputg(x)
@finite wraith huh
what is g(10)
sin(x) if i give it 0 as an input, its output will be sin(0) which is just 0. aka a number.
trece:
just input 10 instead of x to the function g.
i know
great. What is f(84)
g(10)=84

