#precalculus
1 messages Β· Page 255 of 1
I can differentiate them, but that's not enough
then you equate both derivatives to eachother
so you find the x value where they have the same slope
we still need more constraints tho, there are infinitely many solutions
yeah, give me a sec
this is the graph of the equations
there are inifitely many points on the graphs with equal slope
there are inifitely many points on the graphs with equal slope
@novel cargo
thats not the only condition
you need for them to share a tangent
I know
I'm curious how I would set this up algebraically
here's one solution
there is also a second
But, I'm not sure how to set up the equation to come up with the solution
anyway arz you can set up equations for the tangent lines in terms of their points of tangency (say (a,a^2) and (b,-b^2+6b-5)) and equate coefficients to get a system of equations
rip
which you can solve for a and b
you did intrude on a unanswered question
use #questions channels ig
it was about 20 seconds this time but don't worry about it
I see Sneaky, I tried that path but wasn't confident enough and confused about details
alright, show us where ya got stuck then
yeah, this was from a few days ago.
let me do it and come back in a few mins
thanks btw
I'm sorry, I have to go. Will do this later and come back.
no worries.
how do you find the coordinates of a point on a function when you are given the gradient of the tangent at the point?
are you given the function?
yep
since you havent provided the actual question, ill use f(x)=x^2 with the point where the gradient is 3 as an example
alright
i assume calculus is allowable?
yeah
so $\frac{dy}{dx}=2x$
Sneaky:
yep
Sneaky:
follow?
so 3=2x?
so x is 3/2 and f(x) is 2.25
,calc 9/4
Result:
2.25
thnx mate
nw
hi guys @!@
any one @!@
May someone please help me find the x-int and y-int for the equation x^2+y^2-2x-8y-19=0?
@bleak lance x-int = 1+2sqrt5 , 1-2sqrt5 y-int= 4+sqrt35 , 4-sqrt35
@bleak lance and also if u need the method just hit me up @!@
!@!
the derivative of that is: $\cos{x} - \sin{x} + \sec^2{x} -\csc{x}\cot{x} + \sec{x}\tan{x}-csc^2{x}$
az:
the period is 2pi starting at zero
the mins occur when the derivative crosses zero from negative to positive
this the graph of the derivative
I'm pretty sure, you are not supposed to find the zeroes of the derivative
It's virtually impossible to do
I'm exploring. Appreciate if anyone else teaches both of us π
this the graph of the original equation
this also contraticts my previous statement about the mins
the min, not proven, just eye balled, is -inf and it occurs at about pi/2 + 2npi and 2npi
<@&286206848099549185> please correct me and elaborate on this problem, you saints in this dark times
original problem by @viscid thistle
Yes, it is
you can't say the minimum = -infinity
ok
so then it's not -infinity
cause absolute value makes it so that the range can only potentially be 0 -> infinity
is that supposed to be in absolute values?
@rigid beacon yah
that's just the teachers way to make you memorize trig derivatives I guess
its bad idea to use derivitive cuz it six things
theres a intresting method wanna link !@!
?
I mean the only method I can think of involves taking derivatives
but assuming that this is in #precalculus and not #calculus
you don't know what derivatives are
and even then idk for sure if my method works
then use it @!@
what is @!@
I'm also curious
but my only guess would be
ignore the absolute values
take derivative of inside
write it all in terms of sin and cos
get common denominators
set numerator equal to zero
see if that gets you anywhere
@rigid beacon u know bprp ?
Setting derivative to zero doesn't work
Setting derivative to zero doesn't work
@blissful ridge yah
why?
is this from a bprp video?
yah
Addendum notice that k=sin(x)+cos(x)=sqrt(2)*sin(x+pi/4) and we want k to be -sqrt(2)+1.
So sin(x+pi/4)=1/sqrt(2)-1, which is about -0.3, then x+pi/4=arcsin(1/sqrt(2)-1), thus x= -pi/4 +arcsin(1/sqrt(2)-1)
** At 11:42, I showed that those two functions have the same minimu...
lmao lol
so
Watch the goddamn video
to answer a question
that has a solution video
man u good @viscid thistle out here wasting everyone's time
go watch the video @!@
I just wanted the action
I just want you to leave
@novel cargo Thanks for the help, much appreciated.

BRUHHHHHHHHH i was like i ain't seeing it
a lil confused on the signs still
haven't done logs since algebra II and this is my summer assignment for ap calc lmao
log(ab) = log(a) + log(b)
is that why the first sign is a +
yes
the remaining signs are - due to distribution
gimme one sec to consume this info and make sense of it cuz i think i understand but i'm still a little in the mud
okay so why doesnt the log(ab) = log(a) + log(b) apply to the other ones
it does
$-log(ab)= -log(a)-log(b)$
maleb1964:
OH THE FIRST LOG is positive
\log
the second one is negative
therefore the first sign would be positive
i got it i see it yessss
maleb1964:
that didn't do shit
lmfao
also recommend to always put parentheses around your arguments
(spacing is not a substitute)
that didn't do shit
Wdym? it went from ugly to nice, i did not say to use {} that was all your choice mate...
its not recommended to write $(y+2)^{1/3}$ on top of the $\cbrt{y+2}$
ramonov:
it will only result in confusion for the reader
anyway recall the distributive property from earlier.
-log(ab) = -(log(a) + log(b)) = -log(a) - log(b)
h(t) = t2 β 2t
h(x + 5) =
consider also 4 = 2^2
could soeone help me solve this please π
and
also recommend to always put parentheses around your arguments
could someone explain to me how to solve this please functions killing me haha
h(t) = t2 β 2t
h(x + 5) =
$\log_3(y+2)^{1/3}$ is interpreted as $(\log_3(y+2))^{1/3}$. you should instead write $\log_3((y+2)^{1/3})$. Same for the $\log_3((x-2)^2)$
ramonov:
okay thanks i was a little confused on what you meant
@plain root isnt it just 2(x+5) - 2(x+5) i honestly have no clue, functions are in the deep parts of my brain
i'm also dumber down atm
dumbed
same and i'm still stupid
i'm doing ap calc this year (senior) and i cant do basic log shiz
i need to relearn this stuff
i literally just forgot how to do it and got a 20
on my quiz
look up function notation
that's tough i'm sorry man
hahah its fine i can drop the quiz
also feels like you copy and pasted it directly from somewhere,
use ^ to denote exponents
not a big deal but now i just need to waste my time relearning this
@uncut mulch u talking to wham?
that comments was aimed at wham
i think they mean format
what's not allowed is complete disregard for symbols
disregard for symbols?
@plain root is anything an exponent
$t2 - 2t$ is trivially $0$
ramonov:
i think i see what i did wrong
that's what i was thinking
some dumbass error
hahahahaha it's okay i misread a 100 for a 10 earlier
and I highly suspected the superscript formatting was lost during copy pasta or something
fair assumption
i forgot a -
oh yikes hahahaha
@uncut mulch what did u mean by recall the distributive property again, i mean i get the property but not sure how it's going to further assist me at the last statement
that was intended to address the incorrect signs present in your work
oh damn i got more of those?
i'll take a look again
ah shiiii
is the third sign supposed to be a negative
yes
okay that has been fixed
there's a rule with that
recollecting thoughts unless ramonov beats me to it π
replace t with -x, use parentheses appropriately and simplify as needed
4 = 2^2, so the first log could be simplified further
that'd just be x^2
ok so the - just goes away?
well (-1)^2 = 1
ya
negative times a negative is a positive
what are you getting?
/ x^2
are you using the appropriate parentheses when entering your answer?
nice
and @uncut mulch why would i do smthn to the 4
like i get it can be broken down to 2*2 but what significance does that have
2^2 an you can apply the power law
log_3(3) can be simplified to 1
also a slightly misplaced left parentheses
oh the second line right
yeah
okay i'm supposed to be getting a 6log base 3 somewhere and i don't see that happening π
6log base 3 (x-2)
this one killing me
did you copy down the question properly
that was directed at staepled
my bad
i'm checking
for your question, you have a piecewise function
that behaves differently depending on the value of x
specifically for values less than or equal to 1, f(x) behaves like x^2+4
@uncut mulch yes i did
yes
can you show exactly what the answers are saying for the log question
yeah
it might be wrong tbh
ive been using that to check my answers at least, it's been alright
i figures but the third log on the fraction doesn't change
its equivalent to what you reached
i see that now, why didn't the first log get multiplied
nope
rip me
subtraction converts to division
aw crap
also appropriate parentheses
yes
looks ok
that's a start
ive been doing math for almost 4 hours this sux
how do i know whether the z goes on top or the bottom
How do I evaluate a function that's -f(x)?
@bleak lance i'm looking for ya
Thanks!
@bleak lance okay so you just take whatever the whole function itself is and negate it, like f(x)= 3x + 2 and ur looking for -f(x) so u do -(3x + 2) which is -3x-2
What if it's a fraction?
its a reflection over the x axis
For example 2x+3/9x+1
i don't wanna be wrong so gimme a bit
Yup.
i think u might switch variables but honestly don't know i gotta find my better notes
I got it. I just needed to distribute -1 to the numerator.
okiiii my bad dude
Its ok.
I'm stuck on f(x+h)
Here's my work so far. 7(x+h)+9/9(x+h)-8=7x+7h+16/9x+9h+1.
what're you tryna do
Evaluate the function which is 7x+9/9x-8
How do I say all real numbers not equal to 5 in interval notation?
(-inf, 5) βͺ (5, inf)
I need help finding (f+g)(4)
what is the question?
I figured that one out
Hold on
Itβs f(x)=5x+9; g(x)=7x-8
And now Iβm stuck on (f/g)(4)
Does that mean f(4)/g(4)
But f(4)/g(4) isn't 14
How do I do that?
Oh I did t see it that way
So I literally just plug 4 in for x?
Sorry guys I mean (f/g)(1)
@glad pasture not quite.
is it (-infinity,-3]u[2,infinity) ?
capital U for union in plain text
ok
f(x+h) = x+h/(x+h)^2+1
I think I know the answer but I want someone elseβs opinion on it cuz it seems to be too easy and Iβm not sure if itβs a trick question or not
Not a trick question, haha.
It's pretty direct
You could go further by distributing the square
Hi guys
I want someone who can do VC with me and can clear my doubts related to calculus with kinematics
Anyone?
<@&286206848099549185>

iβm not sure if this is even pre calculus but how do u find a slope of 3d coordinates
I think I know the answer but I want someone elseβs opinion on it cuz it seems to be too easy and Iβm not sure if itβs a trick question or not
@empty iris You can just replace x with a+h
iβm given the time and the coordinates at that time is that solvable
actually i figured it out all good
can anyone help me out with this? i've been stuck on it for a few hours now π
<@&286206848099549185>
If your question has not been answered for a minimum of 15 minutes, you may use the Helpers tag once. Please do not try to bump your question using this ping unnecessarily. Do not abuse this ping. Do not individually ping users with the Helpers tag without their express permission.
what have you attempted in your hours of work
set up a system of equations using (m/n^2)^a*(m^2n^3)^b=m*n^(-1)
How do i do thisss, this is circle btw
what do you want to do?
How do i do thisss, this is circle btw
stare at the equation
proof by intimidation
-2x^3+6x+3=0 How does one find the roots of this? ._.
Quadratic formula or completing the square
mmmh have u tried it?
yeah just guess and check stuff with synthetic division after using rational roots theorem
after doing that you can use quadratic formula
or maybe factor some more
write the exponential function f(t)=1238(5^-1/4) in standard form f(t)= ab^t round b to 3 decimal spots
im confused can can someone help
-2x^3+6x+3 an irreducible cubic btw
Ryan - 'Paul Kreinheder':
?
Yeah
Ryan - 'Paul Kreinheder':
?
Yep
thx
Can anyone remind me how to approach this problem? Am I using trig identities to break it down?
divide by two, take the square root
Ryan - 'Paul Kreinheder':
Then take the square root
Then you'll get sin(x)=1/β2
You know what angle gives you 1/β2 right?
Relative and absolute extrema. The term extremum (extrema in plural) is used to describe a value that is a minimum or a maximum of all function values. Function achieves relative maximum or relative minimum (relative extrema) at points, at which it changes from increasing to decreasing, or vice versa.
...?
@viscid thistle idk how they got that answer
What are supposed to find with those functions?
Finding Values for Which In Exercises 43, 44, 45, and 46, find the value(s) of for which .
im not quite sure what its asking
bro those r the directions
Finding Values for Which In Exercises 43, 44, 45, and 46, find the value(s) of for which .
the problem is the screen shot above
i have no clue how they got those answers
Finding Values for Which In Exercises 43, 44, 45, and 46, find the value(s) of for which .
This has no meaning
f(x) = g(x)
Like tf
i forget how to solve these its prob stupid easy
yep
i havent dont math in like 8 months
this is my calc class bro
not even pre calc
im literally in college doing this stupid stuff
this aint considered calc lmao
Idfk the us weird ass names for contents, but i still think you are trolling unless you give us a pic.
Are you American?
...
i am
im literally in like a top 40 cs program and we do this stupid math
yep ty
@jaunty spruce write out the definition of (h o g)(x)
it's h(g(x)) correct?
now what do you do here
hog
Is there anything I can do to gain a more intuitive understanding of precalculus?
Like how does it relate to real life like min, max, domain, range, etc?
3blue1brown has a youtube series on it that aims to do exactly that
how do you write f'(8) in dx/dy notation?
you mean dy/dx ?
$$\frac{df}{dx}(8), \left. \frac{df}{dx} \right|{x = 8}, \left. \frac{d}{dx} \right|{x = 8} f$$
TTerra:
are a few of the ones i've seen
last one is probably uncommon
oh right okay
thnx
first two are most common i'd say. that's all i can come up with off the top of my head
I think my precalcus course may have turned into calculus because it wants me to do something with a secant line.
Correct me if I'm wrong?
Different quotient
I gotta learn so much.
this is the beginnings of calculus, yes
isnt secant just the tangent at a point
but it's not necessarily "calculus"
Huh. What is it? Just advanced algebra?
precalculus is the best word I can think of
looking at secant lines formed by points getting closer and closer is like
how calculus is usually introduced it seems
well, how the derivative is introduced
because that's what it is
so i guess it's precalc
because it precedes calculus
we all do π
That's what the discord and the internet and youtube are for lmao
True.
I wished I could just watch one video that would make everything click for me.
any hints on how i can find eachh unit vector?
I'm asked to find 2aβ 5b
you can't and you don't need to. what are you asked to evaluate?
@willow bear oh..
yeah, you can find 2a Β· 5b without calculating a and b individually, since you know the value of a Β· b
unless you're allergic to multiplying single-digit numbers together
whom pung
yes
yes
yes
yes
yes
yes
no
no
Yes
ε―Ή
If x + 1/x = 5 then find the value of x^3 + 1/x^3
cab sineibe help me with this?
can someone*
what i did was just solved the quadratic
can i just sub in the two values?
is cool
zero
Hey, i have a quick question on my precalc hw, im doing number 59. Iβve discovered the pattern on how to get the imaginary part, but not the real part.
If anyone knows the pattern here, I would appreciate the help.
ah I see, so the imaginary part subtracted from the real part becomes the next term in the imaginary part?
i can't believe you are learning imaginary numbers in precalc
what grade is this?
Jesus is this US?
yes
US curriculum is def tougher than Canada's
I mean I am 2 years ahead of standard, but I don't know much about the candadian system
me too!
we got to the same school m8
oh...
ur all good
you'll probably cover the advanced stuff in college though, so no worries
yup
i got 3 math classes coming up in first year
linear algebra, derivative calculus (which i have ap credits for), and integral calculus
im kinda scared
linear algebra poggers
how hard is linear algebra
i just know the basics
like adding and multiplying matrices
maybe start reading, self learning in advance
yeah im doing BC next year
I mean, do Khan + a textbook or stuff.
take as many ap exams as possible. I regret not taking enough ap tests
don't rely solely on school curriculum if it sucks
ok
Im stuck with 7 courses per term in first ytear
yes
i just did ab
personally, i think BC is better fit for me
and ap chem which i totally bombed on cuz of this stupid corona online exam
I see, I am skipping ab and deciding to go to bc next year
Lmao i retook ap chem test 4 times
ye
oof
but still counldn't submit cuz server kept on crashing fr
yeah that was common occurence from what i've heard
yeah
i am taking apwh and apcsp this year
same
wait yall americans are kinda obliged to take a lot of ap exams to get into college right?
lol yeah
next year, apcsa, ap calc bc, ap physics, apush, and ap english (:
but the SAT score is what counts more
damn
it sucks
SAT, aps that's rough af
yeah def
yes it really is
but university of california is removing sat requirement
so thats fun
OH
by 2024 i think
i didn't know university of california is aka berkley lmao
lol
that school's tough to get into
he is from singapore
and rlly hard to sruvive
oh
but idk either
only 1 kid at my school got into waterloo
I mean Arjun has a cousin in every ivy league lol
i also applied to University of Toronto but they lost my application so they couldn't make a decision
aw
sorry mate
yeah
so where are you going?
nice
oh nice
is that school known in the US
?
no
yes
I've heard of it, but maybe that's just cause I have relatives near by
cuz i know 100% Americans know about waterloo really well
A lot of incoming first years at UBC are from India
yeah
idk either
most indians i know came internationally for masters
not undergrad
so idk the whole system for that
what are you majoring in?
is ur uni virtual?
Im going into first year engineering so we just compete in first year and then choose our 2nd year specialization based on our gpa and interests
yes
the entire first year is virtual
what disciplinary are you most interested in
Comp Eng/Elec Eng
oh i initially applied to ubc thinking i wanna major in mechanical
and then i looked at the competitiveness for 2nd year mechanical
oh i see
Canada doesn't like to produce hardware stuffs
ah
makes sense
it's mostly natural resources/software based
oh damn
i could go into software side of things
heard that it's extremely expenisve there
yes
many leave
cost of living
yes
it's kinda shocking that you could barely survive with 100k in the bay area
yeah
I mean its not that bad
Vancouver is pretty expensive too. That's why most ppl move to Alberta cuz cost of living is 2-4 times cheaper and wage is nearly 2x higher in Alberta
oh
oh what
but i have heard they are crappy drivers
oh
albertan drivers are big memes in BC
Vancouver side a lot of turns
rural side of BC is like straight
and deserts
this is basically east side of BC
bruh thats low res image
west side of BC
u did em dirty
yeah
lol ppl in vancouver don't travel
how about georgia
so soon boys
i heard georgia is full of good minded christians
yeah
not like those white power ppl in mississippi
georgia?
ye
woah
haha, I mean most of California by land mass is red necks lol
i thought georgia was like the safest state
georgia is good
it is now
i went to california LA before
oh god
we are talking 200 years ago
it was quite scary
oh yeah
yeah I hate LA
lots of crackheads
lmao yes
LA isnt great imo
there is a huge problem with managing the city
some guy was beating the hell out of our hotel door and was begging to be in
the thing is, in metropolitan areas yes
both republicans and democrats
oh
but it is like big retirement community
i hear some wild stuff from florida
but rural in California and florida is redneck
so lots of republicans
oh
oh yeah, Florida is crazy man
yes
Would not want to live there
seems like US is like either democrat or republican
its ok tb
lets not generalize
yeah, people chose party over people
political parties are personality traits now lol
yes, the two party system is quite strong
in canada, even the most right wing person supports gay marriage
yeah, on the global political axis our democrats are even right wing
they care too much about ratings
lmao
im ready for the migration
This method is rather tedious to compute the sum of 10 terms, so I'd appreciate some help in figuring out a better method.
Manan:
General term is
$tan^{-1} \left(\frac{1}{n^2 + n +1}\right)$
Yeppp
The Godfather:
$n^2 + n +1=(n+1)^2-n$
The Godfather:
Makes sense.
We need to make it telescopic
Ooofff telescopic sums; I so hate them.
Aight I'll give it a try now, thanks for helping out again!
hey can someone explain how subbing in 2 in the second integration leads to 16 and -18
line 3 is continued on line 4
yes
so basically
line 3 is the first square bracket, line 4 the second
u sub in 5 and 2
i was just really confused how 3(2)^2 leads to 16
and 11(2) is 18
am i missing something here? xd
line 3 is the first square bracket, line 4 the second
the second square bracket's evaluation is on line 4
I have a question.
So I was asking my counsleor if I can be bumped up to Algebra 2 since I was taking Geo at home. I emailed her and she said that Pre calc will be a struggle and if you dont take geo at school you aint gonna be ready.
What is Pre-calculus about?
Usually the final functions necessary to do calc. The course will finalize:
- Higher degree polynomials
- Trigonometry
- Exponentials and logarithms
I personally am of the opinion that much of hs math is skippable with enough effort, the right mindset, and the right reading material.
But if your end goal is good grades, why bother skipping?
@marble locust
You could probably learn this in Algebra 2 right?
Take the pre Calc course on cemc open courseware and see how you feel
If you can do the extension problems you are fine
Cemc
I donβt understand how it is wrong tho
I checked both the limit on both function and they donβt match? Am I missing something important
pay attention to where the limit is being taken.
so, 4 is only part of the domain of one of the equations
it's not $\lim_{x \to 1} g(x)$, it's $\lim_{x \to 4} g(x)$
Ann:
it's not at the meeting point of the two conditions.
it's entirely within the "x>=1" condition
i'm pointing out the dissimilarity
Sometime they told me to check both, and sometime only 1 condition
is 4 >= 1 or is it between -8 and 1?
Obviously the first one
then act on it
^
how did you get 2, I' curious?
what's the definition of the existence of the limit?
Something that is distinticely known as a border
the function isn't continuous at -3
in other words, approaching -3 from the left does not equal approaching -3 from the right
How do you know
-7 <= x <= -3 is the domain of sqrt(7+x)
x > -3 the domain of x^2-5
-3 lies on the boundary of the first equation
sqrt(7-3) = 2
(-3)^2 - 5 = 4
so, at -3, f(x) changes abruptly from 2 to 4 with no values inbetween
Iβm not sure what they mean on letter b for this one. Iβve separated the real and imaginary parts by placing them on opposite sides of the equation, but Iβm unsure how they want me to create 2 separate equations.
Compare the real and imaginery parts
This is what I have: a^2 - b^2 = i - 2abi
What do you mean by compare them?
No, what you are doing is not the way to go about it
if a+ib=c+id
Then it means
a=c and b=d
Comparing the real and imaginery parts
the angle is obtuse and doesn't have a complement
how does this even work?
i understand that as angles, these values are equivalent
but idk it just feels wrong when they are written as values like that
I'm having a rough time. It says to use a coterminal angle to determine the exact value....but it doesn't show how to find a coterminal angle...
do I just keep subtracting 2*pi from the angle until I get the lowest possible ?
I found the vector of <4,7,6> - <1,2,3> = <3,5,3>
and cross product with (1,1,1) to get (-2,0,2)
not sure if i'm right, and what's next?
I haven't learned this topic yet but one equation that you could set up is as follows:
1 + 2a + 3b = c
now you need two more equations
from the line equation you can get other points on the plane to set up the other two equations
take t = 1
if the cross product equals (-2,0,2)
then the point (5, 8, 7) lies on the plane
set this up for another equation
continue Kanga
hang on I need to calculate some stuff
since you can define a plane with one point and a line (provided the point isn't on the line), you can use the three point (two from the line, one that was originally provided), to set up three equations and solve a, b , and c
ok your cross product is correct
now the coefficents of x,y,z should be the same direction vector that you found when using cross product
and you know that the coefficient of x is 1
therefor you multiply that direction vector by -1/2 to make the x-component 1 as follows:
-1/2*<-2,0,2>=<1,0,-1>
therefore a=0 and b=-1
now you can use az's equation to find c: 1+2a+3b=c
1+2(0)+3(-1)=-2
therefore c=-2 @ornate wolf





