#precalculus
1 messages · Page 47 of 1
Instead of checking the tangent line at x you do it at the y
Hello guys
I always manage to fail when it comes to trig equations with restricted range of solutions, for example cos(x) = 0 but x € [-pi;pi]
Am i right if i just get the general solution (pi/2 + pi*k) and then i just substitute k with random integers (for example, -1, 0, 1 etc)?
And then i just check whether the solution is within given range
I recently just got in pre calculus class and was talking about circles. I've been stuck for 2 hours in this assignment I have which is
"Find the equation of the circle that passing through p1 (-3,6), p2 (-5,2), and p3 (3,-6). (General equation)" I watched a tutorial video with each having different methods, I had done the equations 1,2,3 and so on. Doing the elimination method. But I just don't seem to know if I'm doing it correctly
P.s I even used some ai like chatgpt and IT MADE MY UNDERSTANDING WORSE
don't use gpt, show what you did
Dont use chatgpt with that stuff
It spits out nonsense 99% of the time regarding math
So I followed this video tutorial BUT IDK I'M NOT SURE IF I'M DOING IT RIGHT
I did the equations and subtract the equation 1-2 which you'll get the equation 4 and 1-3 which would be your equation 5, after that you'll subtract it again
I DONT KNOW
"Find the equation of the circle that passing through p1 (-3,6), p2 (-5,2), and p3 (3,-6). (General equation)"
The equation of a circle is (x-h)^2 + (y-k)^2 = r^2
Where (h,k) is the center
Thats the general equation if i recalll
You can easily solve for r with the information given
its more or less the same, you end up with a system of 3 equations
one thing that stands out is the notation issues
when squaring stuff like -3 and -5
you MUST have () around them
${\red{(\black{-3})}}^2$
I don't know if I'm even doing it right anymore:( I'm lost
ℝαμΩℕωⅤ
can't check every single detail
but you seemed to have reached a system of two equations
try solving that to get the values of D and E
I don't even know, like can I get the value of D or E in this equation "(16 + 2D + 4E) - (-6D + 12E)"
What did I do wrong T-T
if you want to approach it with elimination,
you'd want the magnitudes of one of the coefficients to be the same before you add/subtract, depending on personal preference
which can be achieved by multipling one or both equations by an appropriate value
If I want to eliminate D for example
I'll multiply
16 + 2D + 4E to 6
while I'll multiply -6D + 12E to 2?
ooOoOooOoOo
you can be more efficient considering lcms
considering that the lcm of 2 and 6 is 6,
its sufficient to multiply that first equation by 3 or -3
IDK IF IM DOING IT RIGHT
<@&268886789983436800> political shitpost
Solve for the ctr of the circle by solving for the intersection of the perpendicular bisectors of two pairs of points
At least i think that should work idk
Yep that works
Whats a fucking GPT Im interested 
maybe it is what it sounds like...
i don't think we wanna know
💀
I wish it is what it sounds like lmfao
Real
🗿 💀
Hello can anyone help me understand this?
tan theta represents the slope of the red line
If you change the angle by 180 degrees, the point will become directly opposite and thus have the same slope
Same for 360 deg ofc
hello,can anyone help me? I don't fully understand what I'm doing
that's a cool problem i reckon
So ok
1x - (-1)y = -3
and
7x - (1)y = 7
We need to do 2 things:
- We need to find the intersection point, because bisector has to pass through that
- We need to find the slope of the bisector
For 1 we can just solve the system of equations to get
2 is cool i think
because
1x - (-1)y means that for every 1 unit to the right the line goes 1 unit down.
7x - 1y means that for every 1 unit to the right it goes 7 units up
it would be nice if there was some system that represents rotation with pairs of numbers...
oh wait
it's the complex numbers
so
-1 + i and 1 + 7i represent the angles
we can multiply them together to get double the rotation
(-1 + i)(1 + 7i) = -1 -7i +i - 7 = -8 - 6i
but the problem is that we actually need their average
which means that we need to find the square root of that somehow
Angle bisector?
Wouldn’t basic trig suffice
i mean yeah but that's boring
(a+bi)² = (a²-b²) + (2ab)i
(a+b)(a-b) = -8
2ab = -6
a = 1
b = -3
works
1-3i
What’s with my enter key today
it was better when it just said "actually they're based"
Same thing anyway
My god I just wanted the image
But the trig part is from that right
Oh nevermind it's just vectors 😭
you get
x = 1/2
y = -7/2
and then from part 2
3x+y = c
3(1/2) + (-7/2) = c
c = -2
3x+y=-2 is the line
on one hand we got lucky that the sqrt is nice
on the other hand we got unlucky that we had to do this by hand
that is unfortunately the wrong line: you have bisected the obtuse angle
luckily the fix for this is to make one of the sides negative
the correct version of the distance to a line formula has absolute value signs: for example, if we have |x| = |y| and x = y doesn't hold, we must thus have x = -y
then it's literally just:
I had a feeling It was, I was watching a obtuse angle solving question. I thought it was the same thing for acute, turns out not to be correct. 🤔
I have another approach using the angle bisector theorem actually:
the point (0, -7) lies on the blue line and the point (4, -7) lies on the red line, and their intersection is at (0.5, -3.5)
so using the angle bisector theorem
our bisector must pass through $\left(4 \cdot \frac{ \sqrt{0.5^2+3.5^2} }{\sqrt{0.5^2+3.5^2} + \sqrt{3.5^2+3.5^2} }, -7 \right)$
wait that's not right, I checked on Desmos
WAIT WHY IS 2 YOUR DENOMINATOR
that explains everything
i did say I didn't know what I was doing 
yeah
south
simplifies down to (5/3, -7)
question: how to know if I've bisected the obtuse angle or the acute angle.. ( teacher hasn't taught us yet )
if you calculate the slopes of the two original lines, you get -1 and 7
from slope = -a/b
so that means the bisector has to have negative slope, if you make a sketch
now, you can check the coefficients of x and y in here
if 0 is on the RHS, you get y/sqrt(2) + y/sqrt(50) so positive
and x/sqrt(2) - 7x/sqrt(50) so also negative
so the slope -a/b will be negative * negative/positive = positive
so that means that if you choose the positive sign on both sides of the equation, that's the wrong bisector
you need to make one of the sides negative
hmmmmm, ok, i can comprehend what you just said. I'll do the rest, Thank you c:
no worries!
if there's a better method it's probably more slick
but you need to figure out which of the angles is acute which depends on the two lines so it can't be that short I think
nw
Can I get some help with this one pls... it's expaded to standard equation of a circle. I used the method my teacher used for the later question but my classmates all have different answers on no.4. I genuinely don't know what I'm doing...
I've been up the entire night trying to figure out which part I got wrong...
Hi im not rlly sure where to ask this but i just started pre calc (only half way through functions unit) and am kinda annoyed there r still word problems theyre actually the bane of my existence. I was wondering if they get easier in the future with calc n uni math
it might get easier in the sense that you will be already familiar with word problems
how hard your problems are really depends on your teacher tho
it might get "easier", might get "harder"
when you are familiar with the terminology, there shouldn't be too much of an issue setting up the equations
whether you have difficulty solving those is a separate issue
32/4=8
You made an error when factorising
I see thank you!
Yeah its just setting them up
Uh Im kind of confused because it looks like none of the options are correct
Im pretty sure its the top one
it was
Do you understand why?
All goodie then
Yeah thats basically it : )
: D
yeah for this one you have the intiial set up correct
you can just check both lines and see which does have the positive slope as someone lse said
but are there any other angles that satisfy tan(theta) = 9 between 0 and 180 deg?
oh
so 180-83.6
= 96.3 ?
when i added 180 to 83.6 i got (263.7)
which i discard because is over 180 degrees
nah wait what
there aren't any other angles what am i on
i have no idea why thats not correct 💀
have you tried putting in 83.6 just in case they round wrong?
or u only have so many tries 💀
can you ask your teacher?
i emailed her on friday but no response
dang
I checked multiple times
and notice that for that specific problem i had to put the degree sign
which didnt really make sense because the answer was telling me to put in degrees already
but thank you for your time and patience!
bruh
how do you even put a degree symbol 💀
is part of the program?
💀
I found someone saying that it was possible to solve a linear system using matrices, and he showed this equation. Can someone tell me what the name of this method is and if it really works? I would like to learn more about it.
rx + sy = t
the inverse matrix
(That was also asked in #prealg-and-algebra, with more answers there).
Would a quadratic model have small residuals and the residuals plot show no pattern?
hi,
i just wanted to double check this problem
my answer is -sqrt3
is that right?
🙂
yep
Uh let's say there's a type of sequence that is defined by two seed values
F(1) and F(2) and F(n+1)=F(n)+F(n-1) basically the fibonnaci sequence but for any two seed values
How can I determine if two pairs of numbers belong to the same sequence
Like for example for the normal fibonacci sequence both 2,3 and 1,1 belong to the same sequence
I could just continue the sequence but that'd take a bit long in some cases
If F is increasing you can do a binary search
You can also maybe do mod, and see if it appears in the same sequence
there's also F(1)f(n) + F(2)f(n+1) = F(n+2)
where f(1) = f(2) = 1 and f(n+2) = f(n+1) + f(n), and F is your sequence
There's also some obvious cases where it won't be. For example if your sequence is 2, 2, 4, 6, ... then 7382921 is never in the sequence
how can i use a calculator to get coordinates on a unit circle
i have memorized the method to remember radians and degrees on the unit circle
but i dont know how to figure out the coordinates / memorize them using some kind of rule
so how can i get them with a calculator
well I don't think there's a traditional calculator that can give you the coordinates in (x,y) form
but you know that the x coordinate on a unit circle is cosine of the angle, and the y coordinate on a unit circle is sin of the angle
so if you have the radians/degrees memorized, you can find the coordinates pretty easily off of that principle
but it's honestly 10x better to just memorize the coordinates, makes trig problems so much smoother
Alright ig
idk what that means. Just take the number of turns you want around the circle and multiply it by τ (or 2π) this is the angle in radians. Or multiply it by 360 to get it in degrees. use cos(angle) to get the x coordinate and sin(angle) to get the y coordinate. What are you trying to memorize here?
you want 1/6 of a turn? that's τ/6 radians and 360/6 degrees. Put that into calculator and you have your x and y. Don't have calculator? Realize that 60° is the angle inside the equilateral triangle. Drop height and see that cos(60°) = 1/2. Use pythagoras to get sin(60°) = sqrt(1² - (1/2)²) = sqrt(3/4) = sqrt(3)/2 that's something like 0.85 i think
when solving for inverse values of trigonometric functions, do I have to graph them and/or look at the unit circle to find their values, or is there some kind of equation that can be used
not really any way to find values of trig or inverse trig functions other than known values
anyone help me with this?
300.
A toroid is a rotational body where a plane figure rotates around a straight line that does not intersect the plane figure. For example, the holed wooden ball from the previous problem is a toroid. If the rotating plane figure is a circle, it forms a torus, which is a special case of a toroid.
a) Calculate the volume of a bicycle's inner tube when its inner radius is 25.0 cm and the outer radius is 29.0 cm. The cross-section of the inner tube is a circle.
b) Calculate the volume and mass of a gold ring when the cross-section of the ring is a semicircle, the inner diameter is 18.0 mm and the outer diameter is 19.5 mm. The density of the gold alloy used in the ring is 17.3 kg/dm³.
I'm currently doing the **b) **, and been stuck getting answers like 49.96 or 52 when I should get 51.7
The second picture is is the a), because the two are similar so I think you solve them quite the with the same technique.
The radius of the inner circle is 9 (18/2) and outer circle 9,75 (19,5/2). So the width of the ring should be 0.75. Because you can think it as half of a round ring, it should 9 should be the distance from the origon to the center of the ring (if it was whole).
x^2-y^2=r^2 so then I think you could just (x-9)^-y^2=0.75^2 so x=9+-sqrt(0,75^2-y^2).
Then you plug it in the integral from -0,75 to 0,75 and put (pi/2)*f(y)^2=(pi/2)(9+-sqrt(0,75^2-y^2))^2 as the function. There then comes the problem as I get the answer 49,964.
Find the concavity of the functions in diff intervals $f(x)=\frac{x-2}{(x^2-x+1)^2}$
TᖇᗩᑎᔕᑭᗩᖇEᑎT ᔕᕼᗩᗪOᗯ
set f''(x) = 0 then make a sign diagram
like this, check the first derivativ
Find the concavity of the functions in diff intervals $f(x)=\frac{x-2}{(x^2-x+1)^2}$
TᖇᗩᑎᔕᑭᗩᖇEᑎT ᔕᕼᗩᗪOᗯ
I got the second derivative and got
And I got $x =\frac{4 \pm \sqrt{6}}{2}$ and $x=0$
TᖇᗩᑎᔕᑭᗩᖇEᑎT ᔕᕼᗩᗪOᗯ
I represented them on the number line
,w second derivative of (x - 2)/(x^2 - x + 1)^2 = 0
Isn't $\left(\frac{4 + \sqrt{6}}{2} ,+\infty\right) \approx \left(3.2 ,+\infty\right)$ ?
TᖇᗩᑎᔕᑭᗩᖇEᑎT ᔕᕼᗩᗪOᗯ
cool that's correct (there's also 2 + sqrt(3/2) which got cut out)
If I put 5 and above values I get f"(x) to be positive implying tat at those intervals it's concaved up
cause 2 + sqrt(6/4) = 2 + sqrt(3/2)
But when I put 4 it becomes negative
And 4 is literally under tat interval I mentioned
f''(4) is still positive
No way Ig i did my second derivative wrong 💀
I got $x(2x^2-8x-5) = 0$
TᖇᗩᑎᔕᑭᗩᖇEᑎT ᔕᕼᗩᗪOᗯ
I'm equating the second derivative to zero
Wolfram Alpha tells me you should instead have
6x(2x^2 - 8x + 5) = 0
Bruhhhhh
I saw jn 💀
It was +5
Not -5
My brain
I hate quotient rule 💀
Anyways tysm 🥹😭@willow skiff
no worries
you can literally use Wolfram Alpha and Desmos/GeoGebra to check yourself
30 mins wasted 🤣
next time
Fr 💀
I'll do some other problems now
I'll be back if I need help ✨💫
I’m looking for question a
How do I find the asymptotes of this function and there is 2 horizontal
the horizontal asymptotes are 1 and -1
as x tends to -infinity, you get -x^3 / (-x^3) = 1
as x tends to infinity, you get x^3 / (-x^3) = -1
because $|x| = -x$ if $x < 0$
south
|-5| = -(-5) = 5 for example
@young gust hey which uni do u study at?
Thx
I'm making a graphing calculator
How should I handle asymptotes
I use lines to connect points
So the asymptotes kinda have this vertical line connecting the two ends
How can I detect asymptotes
That depends a lot on what you are using
And a server for that particular language/library will be way more help than here
Uh idk I'm just using raylib
Anyway im essentially just putting pixels
So it shouldn't really matter that much
Yea try some c++ server in that case
Never mind then
The people there told me to ask a math server😭
That's why I came here
Rip- but i mean you need some way to get the derivative and then setting it equal to zero so its more of a language dependent thing, i dont really have enough experience with c++ to advice you directly on this
No I don't need it in c++ I just need a general algorithm
Cuz writing the algorithm for finding the derivative is gonna be too lengthy and im pretty sure there is already some library for that
Whatever ig I'll just search for libs 😭
Hmmm
Bros being played like a volleyball 😭
Recursive refferals 😭
You gotta teach ai the calculations 💀
Well doable
But not recommended
I mean he could use the openai api
Which is doable but will probably be more expensive than coding it himself
how to solve for t with just a calculator?
😐
oh they probably want you to graph it ._.
I had a question about partial fraction decomposition. If you are trying to split say 3/(x^2+1)(x-2), would it be impossible to split this fraction if you are limited to the real numbers? My reasoning is that typically to solve for the numerator of either fraction you need to set each polynomial equal to zero, but x^2+1 has no real solutions.
Sorry if this isn’t the right place for this question I didn’t know quite where to put it
x-2 has real roots, so it is possible
It gave you some free credits the last time i checked
you can set each polynomial equal to 0, but thats just one way
Yea
Well i guess some is not enuff for a calculator
I'll try
Yes, so I guess my question is if it doesn’t have real roots, does that imply it’s impossible. I know that setting each of the roots equal to zero is only one way. Is there another way that avoids this problem? I am only familiar with that method
you can distribute it out, combine like terms. then use the fact that the equality is only true if the constants are equal to the constants on the other side, the x terms are only equal to the x terms on the other side, the x^2 terms are only equal to the x^2 terms on the other side, ect.
then you can create a system of equations to solve
,w partial fractions 3/((x^2+1)(x-2))
Interesting, thank you thank you. I am curious then if you can ever not separate the fraction, and if so what the necessary and sufficient conditions are for that to be the case.
Can somebody tell me how to prove that there are inf prime numbers?
For the sake of contradiction assume there are finitely many prime numbers, say n of them. Then consider the product of all of those prime numbers and add one to that:
$$p_1 p_2 p_3…p_n +1$$
Now you should be able to reach a contradiction from here. Does that make sense?
Squirtle Squad Gang Affliate #1
There are two cases, one where $$p_1 p_2…p_n +1$$ is prime, and one where it is not prime
Squirtle Squad Gang Affliate #1
when finding how many complex zeros a polynomial can have, can you just graph the equation, count the zeros normally, then mulitply the number of zeros by 2?
the fundamental theorem of algebra says that the number of complex (incl. real) zeros (counting multiplicity) = the degree of the polynomial
the number of effort points needed to ping <@&268886789983436800>
(trivial addition troll)
not gonna lie I'm just starting pre calc in school and I'm probably gonna need some help later on but hopefully I don't.
(𝑥 + 1)² + (𝑦 + 1)² = √26 how do I get the radius of the circle if it's already in a radical? Do I get the fourth root?
Same
yeah as its written thats what youd do although i'd just doublecheck the problem again to make sure they didn't mean for 26 to be the right hand side and root 26 to be the radius
Ohhh okay, thanks!
On Sept 9th I'll have to take an exam about differential calculus, subjects are limits, derivatives, numeric successions, functions and so on.
Would you say Khan Academy is a good resource to learn these things?
I'm currently learning trig on Khan Academy, since I lack trig and as I understand it's definitely something to learn before heading to more advanced calculus concepts
its a good place to start
no
how are you reaching that conclusion?
All of these are A = B. A being the coefficient of x2 and B being the coefficient of y2
I saw it from some video
Is it wrong?
Teacher hasn't really taught us anything, just told us to answer this
its flawed
consider
x^2 + y^2 = -100
would you consider this to be an equation of a circle?
That teacher should be forced to take their own horribly mistypeset exam...
also ^
^ indeed.
Ohhh
No
Ok I think(?) I get it
so here, you'd want to do something like express these equations in standard form
Ah, thank you so much
We can shortcut (6) and (7), because once we find even one point where the LHS is <= 0, the equation must make a circle somewhere
Hi! One question: can I use Lambert’s W function for solving this equation? 2^x = -x^2 -3x +44
Looks unlikely.
The typical way to check is to type the equation into Wolfram Alpha and see wether it produces an expression that involves W.
v and w and v+w are referring directly to vectors, not magnitudes, right?
💀
i feel kinda stupid i thought they were talking about magnitudes and i was like erm no 🤓
yea i think its just the vectors themselves 💀
Yea they're talking about the vectors not their magnitudes
Classic tail to tip vector addition
Physics class ahh addition
yup
wwwut 💀
wdym?
Can someone help me out! I don't understand how to do arcsine, arccostine, and arctangent problems like this without a calc
you don't need to at all
show the options of the question
but to get the principal angle, you just keep adding pi until you are more than 0, cause the period of tan is pi
Ok thats an old question so heres a newer one
oh I think you do need a calculator for this
you can figure it out though without one
Yeah... I was wondering tho is there a process to get it without one
from the options
the range of arccos is [0, pi]
because cos x passes through (0, 1) and (pi, -1)
so when you take the inverse, those points are now (1, 0) and (-1, pi)
we have chosen those two points cause that's the largest domain where cos x is one to one
[-pi, 0] also works as a domain for the inverse, but that's a bit weird to have only negative numbers
ok thanks i figured out how to do it manually lol
nwnw
Yo how to do I solve
( 16x² + 96 + 2,304) + (16y² - 40y +400) =315
Idk how to solve cause the x has a number
Ps. Pls tag me if u know the answer
there are no solutions if x, y are real numbers
what are the conditions on x, y?
that's weird
,w (16x² + 96 + 2304) + (16y² - 40y +400) =315
you see that -4x^2 - 615 < 0
I'm pretty sure this is just a circle
oh should be 96x
nope discriminant still negative
,calc 96^2 - 16 * 2304
Result:
-27648
it is but in the complex plane
Yea the radius has a negative sqrt
hello! can someone help me understand this?
This was actually a quite challenging problem 
Do you know that the intersection of angle bisectors of a triangle is an incenter?
The only method I can think of is to find the equation of 3 angle bisectors and then find their intersection which is the center of the circle inscribed
Actually we only need to find 2 angle bisectors
Wait we still need 3 to locate incenter exactly 
Even though, this method can still lead to correct answer but it is quite long so I don't know if anyone has a better method
well notice your triangle is right angled
x + 2y - 5 = 0 and 2x - y - 10 = 0 are perpendicular
from the above diagram we first solve x + 2y - 5 = 0 and 2x - y - 10 = 0 to get (5, 0)
then solve the other two equations similarly: the sides are 3sqrt5, 4sqrt5, 5sqrt5
so r = sqrt5
now note the square in the diagram: the vector (-1, -2) is perpendicular to the line x + 2y - 5 = 0 and the vector (-2, 1) is perpendicular to 2x - y - 10 = 0
both vectors already have length sqrt(5), which matches the radius
so the centre is just (5, 0) + (-1, -2) + (-2, 1) = (2, -1)
Yeah, I also got that answer
there's a way to solve this that uses stupid amounts of linear algebra (use cramer's to solve for vertices, cross product to solve for sines of angles (or you can just find side lengths, that's easier), then use barycentric coordinates to solve for incenter)
Angle bisector theorem + partioning a line segment moment:
hi, could someone help me with this ?
This isn't a function right?
what's your reasoning
Each value on the horizontal axis (independent variable) corresponds with only one value in the vertical axis (dependant variable) right?
you know why I dont like cos and sin and stuff like that
because I have to use calculators for them and it is depressing to not be able to calculate them
not everything is a nice rational value
best get used to that now rather than later
Depends on the problem. You don't always have to use them
Have u learned about trigonometric identities?
I think it's a function
Because a vertical line only intersects the function once for every point on the function
Do u know what those points say?
It's like, imagine a vertical line intersecting those filled and empty circles, and x=a on that vertical line. The function must only have one value f(a) on x=a, and that value is the filled dark circle. The empty one is like open ended, it approaches a but the true value at a is the dark circle
And pls don't confuse a and f(a). a is the value on x-axis, f(a) is the value on y-axis
Damn. Your teacher should. Or maybe you can ask ur teacher when something is confusing
But also sometimes it's hard to put smth in words things that u don't even know about
Yeah
Also
We're in online class
And there's no way to contact the teacher
So 😭
I see
Thanks for the help!
Yw
I treat this server more like my teacher than my actual one
I think circle with no dark is means a value in under it is not included
And circle with dark us where a value ends like 5 > x, dark circle goes forever
You can just write it as arrow
I see
Anyone able to VC
Real fast to explain a problem to me
Good karma awaits you
Or just DM
I need a little help
for example, 6.
Desmos and GeoGebra can actually do q8 for you
just type in {0 < x} for example
for the domain restrictions
8a is correct
All good
yeah that's correct
What about the characteristics
just state what you observe
so there are asymptotes for 8 at x = 0 and y = 0, for x < 0 only
yeah
9 is easy
that the graph is decreasing for x < 0 but increasing for x >= 0 etc
yeah you get the idea
Ok thanks man
oh right after x = 7 draw the graph a bit higher than y = -5 ofc
or you can make the slope at x = 7 increasing, that also works
thanks you so much
Thanks again
i need help
What is the standard form of the equation of the circle
what formula am i gonna use?
The circle's standard equation
Is this equation
The one that goes like (x-a)^2-(y-b)^2
Looking for a pre calc tutor to help me review for final. Willing to pay hourly rate
Please contact ASAP
How should I go about substituting this?
Specifically the f(x+h)
I don't know where to put the +h
f(something) is a function that has an input of (something) and an output of 3(something) - 1
So whatever that something is, whether x or x+h, you just put it where the (something) should go
So would 3(x+h) - 1 be correct?
Also, what does it mean by "each replacement value of x"?
Yes
each replacement value is referring to x+h and x in f(x+h) and f(x)
for f(x) though it is obvious
you can multiply numerator and denominator by the conjugate
I'm doing precalc this year, any tips?
Close. (x-h)² + (y-k)² = r², where (h, k) is the center of the circle and r is the radius
And i think that equation comes from the distance from the center (h, k) to every point in the circle. So it's basically a distance formula. As all conic sections are, i think
that's the fractional part of x
so for x, you take off the whole number part, and so your range is 0 <= f(x) < 1
and there's a repeating pattern every 1 unit
Graph crosses x axis: odd roots
Graph touches x axis but doesn't cross: even roots
And mind the sign
i need help with conic sections 😭 i don’t understand how standard and general form works
from the general form, you can always complete the square for both x and y to get into standard form
If i still remember, the standard forms always involve the center point
(h, k)
No that's only for circle
(if there are no cross terms, like xy)
how can you find radius though in this problem
for example
where?
ohhhh
the full form is $(x - h)^2 + (y - k)^2 = r^2$, so you have $h = k = 0$ and the origin is the centre
south
long story short, it's minus h, minus k
because x - 2 makes the graph go right by 2 units
(x - 2)^2 makes the parabola go right by 2 units, so it's the exact same with the circle
ohh okay ,, thanks
is this the general form ?
no
the general form of any conic is $Ax^2 + Bxy + Cy^2 + Dx + Ey + F = 0$
south
Idk how to solve, I need help
find the perpendicular bisector of AB and of BC
where the two bisectors meet is the centre
Bro ngl, I'm very slow at math
no worries
So how? Could u pls give me an explanation can't really understand on how to solve
-
find the gradients AB and BC: $m = \frac{y_2 - y_1}{x_2 - x_1}$
-
take the negative reciprocal, -1/over, the gradients AB and BC: those are the slopes of the perpendicular bisectors
-
find the midpoints of AB and BC: the midpoint of (a, b) and (c, d) is ((a + c)/2, (b + d)/2)
-
y = mx + c for both lines, where m are the gradients in step 2: sub in the x- and y-values of the midpoint to obtain c for both lines
-
solve both lines simultaneously: either elimination or substitution works
now you have the centre -
use Pythagoras to get the radius squared: with point C for example, $r^2 = (7 - p)^2 + (2, q)^2$ if (p, q) is the centre
-
now you can write (x - p)^2 + (y - q)^2 = r^2
south
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TY, I just gotta understand it now, Thank you very much for the help
no worries
@little wigeon i got some messages to you
Im starting college and id like to get to calculus but I have no clue where to start. I've never completed a full math course before but I did ok in the parts I tried. Should I go straight for precalc or is it too far of a jump from not understanding algebra 2?
Can anyone help me with conic sections
If you didn’t understand algebra 2, I would recommend first re doing it at your earliest convenience and then do precal after. If you do this, you will have a much easier time in your calculus journey.
What even was the quadratic formula for? I kept switching schools so I never understood
It’s a way to factor quadratic equations. Decomposing polynomials into factors is one of the key problem solving skills that will help you in classes like precal and calculus.
At the end of the day, your success in these classes is dependent on how much time you take to understand each concept as it is given. Math may seem an insurmountable obelisk currently, but with enough concerted time and effort, that once-obelisk will morph and change, revealing layers of simplicity that make up the most complicated equations.
You too, can see math as others do—just as they once saw math the same way you do currently.
You can be successful.
Yeah I think I can do ok I just constantly changed schools so I never was able to learn anything
I don't really wanna have to redo a class
Especially cause I had no clue what was going on in algebra 2
It’ll suck but if you really think it’s the best thing to do for your understanding, you should.
Circumstance also plays a huge factor. I am sympathetic.
I'm not sure if I should go farther back than algebra 2 cause I missed the last half of algebra 1. I did really good in the first half
Look into the course material and see what it is you’re missing. You could either teach yourself from there or use it to guide your decisions, ultimately.
I really appreciate the advice
Np man. I wish you luck.
Math is extremely rewarding and challenging—however, I’m sure you’ll find your peace with it eventually.
for precalc do i round this to 0
whats the question asking for
generally, you should leave it in scientific notation and round to 3 decimal places
probably
Looks like just a floating point error
should i learn algebra 2 before precalc
yes
its more or less the same
Here a quick question 1^x=2 solve x is a complex number
Anyone know quickly what my teacher means by this
if you know what newton's method is it should be clear
Also that is not precalculus
everything under the sun is precalculus atp 😔
can someone explain this? i got it right from guessing the second answer but why is the identity suddenly (-180-theta)
a typo
nah
i don't believe it is that hard, no
maybe unintuitive at first
of course it depends on how hard the teacher makes it
but like the core concepts are pretty easy
but yea
Fr?
yeah
My older friends struggle
it's kind of overrated imo lol
I just rlly want to get it
the difficulty
im prelearning basically all of highschool, if you enjoy it then why not lol
as long as you put in the work you should do fine
I haven’t been taught it yet in school
Thanks
wait its a crab :O
Bubo
why tf yall talking to eachother in 5 different channels 😭
a talking crab
just chose 1
hes trying to get active
I am a miracle yes
lmfao
🙏
give ppl help in one of the help channels

I’m the one that needs the help tbf
everyone is jealous of your active role
Evidently so
ah
just pretend like you know what you're talking about
they'll listen
💀
But thanks for the calculus help guys that I actually needed
if you ever have questions you can go to #calculus
help channels are the bane of my existence
i dont have time to have an hour long conversation
i wake up every day with 40 notifications
LOL I just reply to the question with random comments like ‘hmm.. that seems difficult’
lmfaooo
I wake up every day
most days
Thanks
i mean somedays just dont sleep and then u dont wake up so
First funny bubo moment
😭
or just sleep and don't wake up
mood
Let’s save this for discussy
discussy 😋
Mhm
crab 😋
OI
crab is not a food pls
It’s been wrongfully labelled as one
on a scale from 1 to 10 how cannibalistic are you
Kindly stop the random shitposting here.
isnt images allowed for everyone in this channel
My bad tropo
my bad
I’ll take it to discussy
Is this website DFM?
lol
nice
i'm bad at conics
c = sqrt(a^2 - b^2) is for ellipse i believe
lol
yeah and the -8 in the x term means its shifted to the right by 8
yea
@fossil cypress
o
we're just doing the problem for him 😂
lmao
wait
do you know the center?
..what
um nvm
(8,2)?
the fact that its shifted to the right means you find the vertices as if it wernt and then just add 8 to the x values of what you got
Hi
If i am quite good at precalculus (i need to get better only at logarithmic and trig equations), and i already know about derivatives, can find extrema of function, have basic understanding of continuity, limits, but i cannot solve harder limits, like i know how they work, but i didnt master solving them, so with this knowledge, can i start learning integrals?
We skipped limits at school and started calculus with derivatives
i did the same as you and i would say - yes, you can start solving integrals, integrals require variety of different techniques and most of them have nothing to do with what u learned in limits
Okay
How do you put this in standard form:
In like this
When I tried to manipulate
this happens
what happens
I guess we'll never know
how do I put it in a form like this?
140y^2/35=(y^2)/(35/140)
and replace $y = \hat{x}, x = \hat{y}$
Transparent Elemental
can you show the algebra?
Divide by 140 on both numerator and denominator
Shouldn’t the 4y^2 be negative?
you're replying to the comment that shows the algebra
140/35 = 1/(35/140)
Then why doesn’t the third step have the (140y^2)/35 positive?
Yes that is in standard form
conics are beautiful
except they arent
shuttuponlyhelpfulshavespeakingrights
keep that line in it
actually the correct statement is quadratic forms are beautiful
but studying them is hell
good
I had a cancer
reading this
how do you put this in equation
The product of the distances of P(x,y) from the coordinate axes is 5.
how far away is P(x,y) from the x axis
Ahem, no, that's not what the Helpful role is supposed to indicate.
~~okay, did you mean that only mods have speaking rights? ~~

How do I write subscripts?
Ye
a sub n
Can you show me the algebra?
(x, y) is y units above/below the x-axis
so how many units is (x, y) left/right of the y-axis?
to the right of/to the left of
💀
corrected haha
Is that not just
y=5
Wouldn’t it just be
x_p * y_p = 5
I think either way it really depends on what you want the equation to represent
You could do an inequality to represent the area that contains all valid points
Unless P represents something beside a point, it’s just
|xy| = 5
Good catch
like (0, -3) is still 3 units away from the x-axis
so basically |xy| = 5
that's the same
You right
Is directed distance the same as r?
depends on the circle
Talking about polar coordinates
what do you mean
if directed distance is like it can be positive or negative
then r can be positive or negative so it is A directed distance
but r is not defined as a directed distance and vice versa
i guess
i'm not really sure what you mean by are they the same
Is there anything I should familiarize myself with regarding Precalculus Algebra? I haven't had a math class in over a year, and old concepts have kind of slipped my memory.
For what class?
Class names “Precalculus Algebra”
ik factoring is a big thing in calc 1 and precalc so you def wnat to get that down
but the rest of the answer guide uses the "typo"
whats that
ඞඞඞ
please help
Thanks!
Am I right?
or wrong?
Right
I mean the computation is correct
Shouldn't be the 2 on the other side? Not sure
could someone help me out with this somebody else asked me for help with it and i don't get it 💀
Let $A = {(x,y) \in \mathbb{R}^2 \mid -2 \leq x \leq 3; , 1 \leq y \leq 4}$ and $B = {(x,y) \in \mathbb{R}^2 \mid 0 \leq x + y \leq 5}$, and let $P = (1,-1)$, $Q = (-2,2)$, and $R = (-1,3)$.
\begin{enumerate}
\item Determine which of the points $P, Q, R$ belong to $A \cap B$ and which belong to $A \cup B$.
\item Let $C = {(x,y) \in \mathbb{R}^2 \mid y = 2x}$. Find $A \cap C$ and determine if $A \cap C \subseteq B$.
\end{enumerate}
help
ඞඞඞ
Jesus
why would it be 0?
,w find the derivative of e^x wrt to e
Wolfram Alpha doesn't understand your query!
Perhaps try rephrasing your question?
Click here to refine your query online
,w find the derivative of e^x with respect to e
Do u mean d/dx ?
no i mean d/de
maybe i don't know what e is and i have some iterative method to find it
and i want to know the derivative with respect to e
i mean it should be xe^(x-1), but why does wolfram alpha say 0
It could be that it's treating the 2nd e as the euler's number and as a result, e^x is treated as a constant
oh
And the derivative of a constant is 0
yeah that's probably what it is
Otherwise just choose a different variable aside from e
This is the expected answer?
Ah yea that makes sense
,w d/df f^x
^here it gives the expected result. Just replace f with e. I conclude it treats the 2nd e as euler's number
I don't know why Wolfram Alpha here won't work
You can get that by using Wolfram Alpha website
Oh i see
youre asking it the derivative of e to the x?
i think its confused
between the power rule
and the e to the power x thing
The guy above wanted to find the derivative of e^x wrt to e so I showed him
💀
why is wolfram confused
💀
It was for the guy above he wanted to find d/de of e^x 😂
lmao
Ur using partial derivative with respect to e
Not to x
It treats x as any random constant
And e as a variable
he meant to do that
he was saying it didnt work on discord but it worked on the website
its confusing anyway XD
Is it possible that discord uses a different version of wolfram alpha?
I've been reading from the past day Ig
No
Why is it not correct? X is just a constant here so won't this be it
notice the difference in the d
Just say that it's d
Maybe they send different inputs to WA?
Might've been the case
Wher
e is a constant, and can you differentiate something with respect to a constant
I think it should be a variable
Not really. this follows from the limit definition
,align y &= e^x \ \frac{dy}{de} &= \lim_{h \to 0} \frac{f(e+h) - f(e)}{h} \ \frac{d}{de} \left[e^{x} \right] &= \lim_{h \to 0} \frac{f(e+h) - f(e)}{h}
ඞඞඞ
.
the variable is probably just whats confusing
lets call e -> y, and x -> a
d/dy (y^a) right?
then you just use the power rule
oh okay
lol
limit definition of derivative
it gives the same result as using derivative rules
.
oh he was saying taking the derivative of something with respect to a constant
in this case, we were treating e as a variable
ye
.
i don't know how it follows from the 'limit definition' of derivative
but it does make sense with rates of change
the derivative just represents the rate of change
dy/dx means you look at how y changes as x changes
ohh okay
so dy/de means you look at how y changes as e changes
except if e is a constant, it doesn't change
exactly, correct
i'm pretty sure that just means dy/de doesn't exist
talking about how it changes makes no sense
thank u for the explanation sir, yeah I was confused why = 0
also catgod used the derivative as limit definition yeah
very unrigorously, i believe de would be 0 because its not changing
and dividing by 0 makes no sense
lol
oh okay
i think this better though
this is kind of iffy explanation lol
yeah when I saw that it was = 0 I shit the bed
i don't know how you would do that, there is no e axis XD
💀
ye
ye
because rate of change mf
i would think taking the derivative with respect to a constant doesn't make sense
e is constant so no rate of change
lmaoo
dy/de means you look at how y changes as e changes
e doesn't change
so this shouldn't be 0 it should be dne
it would be 0 if y doesn't change but e changes
😔
that's what im tryna figure out
u see its 0
i see its 0
ah you know what
it might be thinking of different e
taking the derivative with respect to the variable e
of e^x, this one is constant e
is looking to differentiate with respect to e
and taking (e^x) as constant
cuz the e font is different
e is variable
yea like
its taking the derivative with respect to e of e^x
notice the different e
e is variable, e is constant
exatly
it just misinterpreted 😂
but yeah taking the derivative w.r.t a constant makes no sense
😂
im pretty sure
funny 🤣
It's 0 cuz
X is a constant
So e^x
Is also a constant

Remember constant rule brother
Wait dumbass
note that the e in e^x is bolded, meaning it's euler's number, but the e in d/de is not, meaning it's a variable