#precalculus
1 messages · Page 232 of 1
❤️ thank u so much
❤️ if it wasn't for you I would've not been able to solve it thank u so much
ah fuck i made a mistake
oh
dont say sorry if it wasn't for u i would've not been able to solve that question thank u so much bro ❤️
lol np
hey guys i have a question please
so it it correct if i do this ?
and then factor everything out?
can someone please tell me if thats the correct way of starting
oh
so it would be (k^2+1)^2-4*k^2
so only (k^2+1)^2
Yes
guys how do I solve for this quadratic
i tried using like quadratic formula
and didn't get that recperical thing
are u asking for a or b @full garden
this
k is a constant
like its impossible to get x = -k
yes bro I am jus trying to solve it using the quadratic formula
ok first can u expand the equation
and tell me what you got
then we can apply the quadratic formula
nah u have to expand it
before u apply it
ok good
thank u
can u combine any like terms
yes
combine em
...
that's not combining like terms
do u seem anything u can combine
from the other thing u sent
i dont think i can combine them bro
I can just factor out the common x
and Ig use it for the b
not factor
combine
oh wait
ok
i thought u could combine like terms but i was wrong
u actually have to take the quadratic formula of it lol
okay
i did?
@full garden
i got it if u need
did u get it?
if u still need help here's how u do it https://mathsolver.microsoft.com/en/solve-problem/k { x }^{ 2 } %2B `left( { k }^{ 2 } %2B1 `right) x%2Bk %3D 0
i kept doing it wrong because i forgot u needed absolute values
😅
@hasty magnet thank u so much ❤️ thank u ofc u did even if u didn't help me u still tried which means a lot to me thanks buddy
@lilac pier I tried that earlier put how do I apply limits to infinity on that
denom
numerator approaches +infinity
oh
LOL yeah
actually for the infinity part, write the denominator as 1/x^3 - 6/x^2 + 11/x - 6
so as x approaches infinity, the denominator approaches -6
the numerator approaches infinity since x^3 has the highest power and is positive
so it's something of the form infinity / -6 which is just -infinity
@rapid tangle
Yes, the answer's correct
Thanks
Just got wound up at the algebra part cuz I'm relatively knew to this stuff
if i am given g(x) = 2x+1 f(g(x))= 3x+7 , how can i find f(x)?
plug g(x) in
where
i think commander means sub 2x+1 for g(x) in f(g(x)) so that you have f(2x+1)=3x+7
Zeus wants to know f(x) given g(x) and f(g(x))
What changed between g(x) and f(g(x))? @tender bolt
$g(x)=2x+1$
$f(g(x))=3x+7$
so f(x)= kx + 6
so there is not really any method
Wait no
it is just trying to find it
Hold on
Cant you do something with inverse
you're overthinking it. perform the substitution ramonov mentioned
Im pretty sure theres a legit method with inverse
i just thought it in my had and i got f(x)= 3/2x + 11/2
thats the correct answer zeus
^
oh so i can do 2x+1= u
Eeee
isolate x to get it in terms of u
AASlavoj:
Shouldnt that be f(x)
uh no
f(x)= 2*(x-7)/3 +1
u=2x+1
isolate x from that equation
i did that
obv
thats how i got (x-7)/3
i any case, i got what i needed, i checked also
thanks mans
man*
wait
that notation looks messed up
How can u be two different things
^
extremely hard to follow what's actually being done
How can u be two different things
Animal abuse inside that box
who the fk is Schrodinger?
it is Schrödinger minimized
ö looks like 😮
wtf

lol
How do i solve this
what have u tried
I don't know how to expand xⁿ
The formula wasn't given
Like i solved the prev one where it was a^x
Ok imma try, thanks
Hey..uhh so still not getting it
Sorry, if it's basic stuff but I'm really new to this 😅@serene heath
I could solve it using L'Hopital rule but I wanna solve it algebraically cuz they didn't teach that rule in this book
what did you get after subbing
😶oops sorry i took the wrong limit
Thanks for your help, got it
This is correct right?
Yup
Big brain
My man
I miss u
@rapid tangle good job
Me too lol
How u been
#chill :)
the increments are by 7 @silver matrix
so one line is counted as 7 numbers until that line
it's asking what would y be if x is 2
x-intercept = intersection between the graph of the function and x axis
y-intercept = intersection between the graph of the function and y axis
so f(14) = 0
f(0) = 28
You can get the equation of the "line" between points (0,28) and (14,0) by calculating the slope
m = -28/14 = -2
y = -2x+28
So f(2) = -2*2+28 = 24
@silver matrix
bruh ur not suppose to give them the answer @sour eagle
Why not?
😔
we're here to guide you, not do it for you
Now, here the answer is A. right?
Thanks to his explanation I know how to mechanize this exercises
Yes
hey guys I just have a very silly question
for this one I just plugged 1/x in f
and I got this
but I feel like it's wrong to do that because the question can't be that simple 😅
can someone please just quickly tell me if that's correct please
im not familiar with the notation but if Im assuming correctly, id say it's -2*(1/(-3(x-4)))-5
oh
or when simplifying: 2/(3x-4)-5
cross check with someone else though
it's the way I think the notation is being used
okay thanks buddy I'll check thank u
i havent actually seen this before
sameee
but the way I understand it what's in the square brackets becomes the new input for f
i thought we just had to sub 1/x into f
oh
yes i think ur answer is correct bro thank u
Where did I go wrong?
@rapid tangle 5th line
You factor out an x, but take out the negative sign as well
That’s why you end up with -1/2 instead of 1/2
@signal herald ah yes, a rather silly mistake
Thanks tho
@rapid tangle Where do you go to school? It's interesting that you're learning limits in precalculus, especially using series expansions
So I'm looking at the answer key of my homework but I don't understand where that 3 came from in the final portion of the question.
The 3 that came into 3y
he moved everything to right
wym
multiplied both sides of the equation by 3 to get rid of the fraction
@signal herald heyy so m currently in 10th grade moving to 11th
I'm really just trynna teach myself calculus
Rn I'm following this book called Differential Calculus for Beginners by Joseph Edwards
is that a 9, a or q
multiplied both sides by 12
look
$\frac{(-q-3)}{6} \frac{3}{2} = -1$
Commander Vimes:
$\frac{3(-q-3)}{12}= -1$
Commander Vimes:
though it would be more efficient to multiply by the lcm of 2,6 (which was 6)
$\frac{3(-q-3)}{-1}= 12$
Commander Vimes:
which is the same as $\frac{3(-q-3)}{1}= -12$
Commander Vimes:
do you understand why?
"the cosine of an angle in the unit circle just equals cosine, "
hm
indeed!
well your idea is correct
look
sin is opposite leg divided by hypothenuse
(for right triangle)
and cos is near leg by hypothenuse
so in case of unit circle we have hypothenuse 1
since it is radius
and because of that
x and y components are cos and sin respectively
we define unit circle in terms of circle btw
x^2+y^2=1
hey guys! How do i find the two fundamental solutions for cos(5x+3x)=0.03?
i found one, but not sure how to find the other
hey guys! How do i find the two fundamental solutions for cos(5x+3x)=0.03?
@viscid thistle cos(-x)=cosx
@harsh smelt i appreciate that tip, but im not quite sure how to apply it
i know that my first answer is in QI and my second should be in Q4
suppose cos(10)=0.3
is that where thats heading?
then cos(-10)=0.3
suppose you found solution which is A
then because cos is even
-A is also solution
what if i wanted the solution to only by between 0 and 360
i tried that as well!
basically what i said
how did they come up with 33.965?
Sorry if i'm not understanding by the way! im trying my best!
@harsh smelt ya i think i get it
@viscid thistle You have cos(8x) = 0.03, that means cos(8x) is positive
For simplicity, let 8x = alpha. So you have cos(alpha) = 0.03, which means cos(alpha) is positive. You should know cos is positive in the first and fourth quadrants.
For the first quadrant, you get alpha = 88.28. For the fourth quadrant, it's 360 - 88.28. So you have alpha = 88.28, 271.72. Now use alpha = 8x.
@lilac pier dont just give out answers
no, the domain of tan is not $\mathbb{R} - { n \pi/2 \mid n \in \mathbb{N} }$.
Ann:
$\mathbb{R} - { (2n+1)\pi/2 \mid n \in \mathbb{Z} }$
Ann:
Uf.. I do not understand that 2n + 1
Indeed, I do not understand all this mathematical demonstrations or whatever is called when they add that + 1
it can be rewritten as $R - \curly{n\pi + \frac\pi2 \mid n \in \bZ}$
it's annoying for me
Ann:
Yeah
Thanks
Now I understand why they add that 1
it's a better way the first way but I needed to know where it came from
Is this true? At first I thought it was, but then I said that the domain could be (in interval notation) (-\infty, 2] U [3, \infty)
As the x can have all that values except the ones between 2 and 3
This ones included
But then he says that the domain has to be the intersection between the roots.
What do you guys think?
Yes
The domain of a function is all the values that can produce a result passing through the formula
sqrt x-3 is only defined in R when x>=3
sqrt**(x-3)**
and sqrt 2-x only when x<=2
sqrt**(2-x)**
so the function as a whole has no real domain
if you write \verb|sqrt x - 3| then it is not clear whether you are talking about $\sqrt{x}-3$ or about $\sqrt{x-3}$
Ann:
indeed, sorry
What is hte difference between that example and this one?
I mean the values don't have an intersection either
But here there's a solution
In the other case, it wasn't
Why
This is not solved algebraically, I HATE this explanations
the square root doesn't exist if what is being squared is negative
in either case, you don't want negative numbers under your square roots
Is a circle an even, odd or neither function?
The professor says that techinically a circle is not a function
yes it isnt
It's not a function R → R, which is usually where we talk about odd/even
Could you tell me, even so, if it's an even odd or neither function? It's symmetrical both on the y-axis and on the origin
Oh ok
so it's anything then right?
If it's not a function
then can be neither, nor odd nor even I guess
the question is nonsense
its a relation on the set R
since its not a function
https://www.youtube.com/watch?v=fKyBOLsqRlo&list=PL0o_zxa4K1BXUHcQIvKx0Y5KdWIw18suz&index=10
Min: 17:34
This algebra 2 and precalculus video tutorial explains how to determine whether a function f is even, odd, or neither algebraically and using graphs. This video contains plenty of examples and practice problems using variables and constants. First, plug in -x into the equati...
I don't like how he explain things, but 🤷♂️ this guy makes ace exams
He taughts you how to mechanize things
So
Left as an exercise I guess. The thing is that I've heard about R but I don't even know what that is
They are like planes? Dimensions? Real numbers?
No idea
the set of all real numbers
Ok
I've seen sets in a very basic way
so
So R1, R2 and R3 are then differente thins right?
yes
R^1, or just R, is the number line
R^2 is the x-y plane
R^3 is three-dimensional space in the everyday sense of the word
Can there be R\infty?
Hilbert space
or R0?
or R0?
zero vector?
no to both of these
R^∞ could be understood as the set of all infinite sequences of real numbers
tho it never really comes up bc there's not much you could do with it
R^0 is just... well, you could say it's just {0} but i don't see a use for that except maybe to plug a hole in some definition
So if there are higher dimensions than 11, why the physicists try to invent a theory that explain all in the world with x dimensions?
yeah
what are you even talking about
how can you explain more than 11 dimensions
No, it would be a non-technical discussion about what people are studying today
You can just work with these things algebraically
dimension in math != dimension physically
You don't need to be able to visualize them to be able to work with them
dimension in math is just like roughly standard lenght of an array
the space of all possible configurations of a system is a meaningful thing physicists talk about
and the dimension of THAT can go as high as you want with complex enough systems
I'm just saying that I do not understand why physics try to say that the world is x dimensions when in math you see higher dimensions than that
why does it matter what you see in math
Because the world isn't that high of a dimension?
what you see in math need not have direct relation to anything in the real world
or like
Just because we can think of R^(10000) doesn't mean the world can have that many dimensions?
so math is apart from the world/universe?
direct relation in specifically the way you're thinking of
I mean, there are things in the world that have high dimension in some sense
that explodes my mind tbh
Like data sets can have high dimension
and doesn't makes sense in some way
This isn't the standard "physical dimension of space"
then you are not explainging all
because again, R^n for high n is the natural setting for modeling complex systems with many components and many degrees of freedom
I can have a dataset that takes values in R^(10000)
There's different ways to interpret a vector space. Literally representing "space" is one of them, for which R⁴ could never work
like if you have three bodies interacting gravitationally in three dimensional "physical" space, that's already three position and three velocity vectors - one for each body
and the state of the system as a whole could be expressed as a single point in R^18
up to technicalities as to what that point would ac be
add more components and interactions and the dimension of the state space can be cranked as high as you wish
I have to study more to comprehend these type of things. From a premature perspective I see incoherent listening to a physicist talking about M-theory or whatever theory (obviously in a divulgative way) and then see the group monster with 256 dimensions or whatever that thing is (again, in a divulgative way)
Dimension just can have different meanings?
of course you have to study more to comprehend these types of things
Dimension in these situations usually means dimension as a vector space
So like R^(10) has dimension 10
Self-teaching AIs are really just spicy functions R^10 to R^5 or whatever
i did the math but not sure if its right.
is tan(5x) = sin(5x)/cos(5x)
Yes
awesome
https://i.imgur.com/aCYvzOV.png I got a very long answer, could someone tell me if im close?
https://www.symbolab.com/solver/derivative-calculator/\frac{d}{dx}\left(csc\left(5x^{5}\right)\right)
Free derivative calculator - differentiate functions with all the steps. Type in any function derivative to get the solution, steps and graph
$ csc(5x^5)cot(5x^5)(25x^4)cot(5x^5) + (-csc(5x^5))(-sin(5x^5))(25x^4) $
Bridge:
thanks rent free i see where i went wrong
np
Could someone help me solve the derivative of sqrt(2t)
Do you know how to write square root as an exponent?
Yes
Okay, so once you've done that, do you have an idea for derivative rules you know that would apply to (2t) raised to some power?
Bridge:
Yeah, nice, that's exactly it. There's just one step left. The power rule would be for $t^{1/2}$, but you have 2t inside
finally...
flormulaic:
So is there any other rule you can use that takes care of when you replace e.g. x with 2x or a f(x)?
what?
Do you remember learning about the chain rule?
Sorry, that's what I was trying to ask about
So, can you try applying the chain rule to the steps you've already worked on?
is my equation correct?
Wait why do you need chain rule here
The equation you put above would be for just the power rule. You also need to handle the "2t" inside somehow (using the chain rule)
...
Constant multiple rule
Much easier than chain rule
Original expression simplifies as Sqrt(2)*sqrt(t)
I dont think ive heard of the Constant Multiple rule before
I did not know that was a thing, but it sounds like giving a name to the chain rule of a linear function
Wait, flormulaic do you want me to apply to chain rule to my original equation or my most recent one?
I was thinking about just applying it to the most recent one. The only problem is in the most recent equation you sent, you're just skipping the fact that when you apply the power rule to (2t)^{1/2}, there is a 2t (a function) that you need to pull the derivative from afterwards
Sorry if that's unclear
So you just want me to mutliply $ \frac{1}{2}(2t)^{-1/2}$ by 2
Bridge:
Exactly like that, yes
So the fraction obv cancels
Yes
Ooh ok, so i get 1/sqrt(2t)
I think so, yes
That's 1/sqrt(2t), it just separated the two
Sneaky, I think the rule you're talking about would not pass through a nonlinear function (like square root)
, calc 2/3/4
Result:
0.16666666666667
, calc 2/1 * 4/3
Result:
2.6666666666667
, calc 2/3 * 4/1
Result:
2.6666666666667
, calc 2/3 * 1/4
Result:
0.16666666666667
thank god
. Write a polynomial inequality in factored form with integer linear factors who’s solution is:
𝑥 ∈ [−3]∪[−2,0]∪ [1/2,2/3]
what's that box meant to be before the 1/2
also do you have a screenshot of the problem just in case
i heartily dislike [] used for both closed intervals & set roster
Yep they force it up your mouth in ib lol
well
@prime crypt
if this borders are solutions for inequailty
they are roots of underlying equality
(sounds a bit communistly lol)
hahaha
you’re right, just tried that and got something
just used one of those sign charts to see if the solutions fit for either < or >
aight well ok like
you're gonna want a nonstrict inequality
because (polynomial) > 0 will only ever give you open intervals
Tag helper after 15 mins
okey thanks
I'm thinking something has gone wrong
It looks like whatever goes off the top, comes back at the bottom. With that being said, the amplitude would then be 5
Periodic functions should never look like this lol
Thanks for the answer. I guess the period is 10pi, no?
And what about the formula?
,w graph 5cos(1/5 x)
That would be it. Note that 1/5 comes from 2π/10π
bruh
And this is the Mathematical Association of America
arggg
I'm gonna tell my advisor
very poorly made
My answer?
Yeah, agree
isn't that Webwork as a whole?
Anyone here ?
no
we're all ghosts
Q.29
I have solved this auestion
But i just need someone to check if my logic is correct or not
sure, post your solution
sure
So first i checked for what values of x sqrt(1-|x|) would be valid
As its a square root
It should always be positive for all real values of x
So sqrt(1-|x|) >=0
Solving this inequality we get
x must belong to the interval [-1,1]
good, keep going
And then i just took the intersection of the above 2 sets
And got the answer
Have i considered all the appropriate cases ?
yes
you actually don't need to consider the -sqrt 5 case, since |-1 - sqrt 5| > 1
so looking exclusively at [-1, (-1 + sqrt5)/2] will work
oh wops nvm
i missed the 2 at the bottom
yeah, you did everything correctly, discard what i said above
Thanks 🙂
oh wait wops,
|(-1 - sqrt 5)/2| > 1
so looking exclusively at [-1, (-1 + sqrt5)/2] will work
@pale bison Shouldnt it be a closed like this ) ?
Since the roots arent considered
yes, since you have strict equality, i'm just giving a domain for which they're defined on
Yes 🙂
@viscid thistle but the solution ((-1-sqrt5)/2, (-1+sqrt5)/2) is not an answer in that list. Or maybe im just dumb. Sorry for the ping!
@sour eagle Its alright 🙂 , actually the solution will be obtained after intersection of 2 sets
Thats just one of the sets
Oh ok! Wasn't sure if that was the final solution or not 😅 Sorry again for the ping
Okay I’m absolutely going nuts with Precalc. I have a few assignments left and I just can’t figure them out. I asked some family too. Can someone please dm me so we can talk about these calculus parts of the class (since this server doesn’t like giving me notifications in here 🙈)? I’m just being driven nuts with it and only have a few more days till the school year is over.
@gloomy mortar go ahead and post your work so someone can see if they can help you
@gloomy mortar we have rules regarding dm make sure you review those but your better off uploading a screenshot on here so people can help you. If I can’t see the work I don’t feel confident that I would be able to assist. Good luck 👍
That's all eh
Wow great
No one will have time to walk through all
@gloomy mortar you gotta choose
the general prolem solving method for geometry problems like those in the second pic onward goes like this: Draw a diagram. list or think of relevant formulas(cosine rule, sine rule, etc are going to be especially important here). See if you have enough values to use any of those. If you don;t, look for values that you can find that you would be able to plug into those formulas. Then, do your best to solve.
,rotate
what have you tried?
@raven brook dont multipost.
So I had this question:
Show: 2 * ln(y) = √(ln(y))
2 * ln(y) - √(ln(y)) = 0
2 * a^2 - a = 0
a( 2a - 1 ) = 0
2 * ln(y) - √(ln(y)) = 0
√(ln(y)) ( 2 * √(ln(y)) - 1) = 0
√(ln(y)) = 0, ln(y) = 0, y = e^0 = 1
or
2 * √(ln(y)) - 1 = 0
2 * √(ln(y)) = 1
√(ln(y)) = 1/2
ln(y) = 1/4
e^(1/4) = y
Though I was wondering, why I don't need to put ± next to ln(y), after squaring 1/2, to 1/4
ramonov:
Looks like abs value tbh
$(\sqrt{x})^2$ is not the same as $\sqrt{x^2}$ for all values of x
ramonov:
Hmm, what values?
I guess negative values wont work.
For the first one.
Since it'd be undefined I assume?
depends if you are considering complex numbers
Ah right
eg (sqrt(-1))^2 would be -1
but sqrt( (-1)^2) would be |-1| = 1
Yep, that makes sense
@viscid thistle I still need this much help because people weren’t really helping before, so this has all built up. I guess now you realize why I can’t do it myself. People are refusing to help me
Before I didn’t send many. I sent 13 problems now because it’s built up since people weren’t helping
Aight
I get that it’s a lot but it’s gotten to that much because people haven’t helped. That’s why I really just need someone to help
And I’m coming to here because my teacher doesn’t ever answer her emails
And no one I know irl knows more than the second problem
Or if they have, haven’t replied
-
Note that angular speed's formula is $$\omega=\frac{\theta}{t}$$ and when we talk about time that it takes to rotate once we talk about this formula $$\omega=\frac{2π}{T}$$ where T is the time it takes to rotate once (which you are given)
-
Is basically asking you for your lineal velocity, V. Whose formula is $$V=\omega \cdot r$$ whose r is given on the previous problem.
Next pic: 1) Note that Sine's law is $$\frac{\sin(A)}{a}=\frac{\sin(B)}{b}=\frac{\sin(C)}{c}$$ where A is an angle and a is the side length located on the opposite of the angle (same for letters b and c), example given on the pic. While cosine's law: $$a²=b²+c²-2bc\cdot \cos(A)$$. So for 1 and 2, two lengths are given and one angle, choose which law is more convinient.
From 3) to 6) you gotta draw these.
3) 2 angles and one length given, calculate another length.
-
2 lengths are given (while 90 being the length side) (use geometry here).
-
2 angles and 1 side, pretty obvious to which law you should use to get the other side.
-
Again pretty obvious, 2 sides and 1 angle, calculate the missing angle.
Next pic:
-
2 angles 1 side, calculate side.
-
2 sides 1 angle, calculate angle.
-
3 sides, calculate angle.
Last pic:
-
Again, 2 angles and 1 side, calculate the other side
-
Motion problem combined with 2 angles given, to calculate 3 sides, 2 or them are calculated by the motion equation (you gotta transform the units first) $$x=v\cdot t$$ where v is velocity which is given and time which is given as well, when both x are calculated, use cosine's law for the other length.
Bonus: 2 side lengths, 1 angle, missing 1 side, calculate it by one of the laws. And to find the area, i would use Heron's formula for the area of any triangle: $$A_{\text{triangle}}=\sqrt{s(s-a)(s-b)(s-c)}$$ where s is the semi-perimeter so $$s=\frac{a+b+c}{2}$$ and a, b and c are all the side lengths of the triangle
@gloomy mortar
Al𝟛dium:
Oh god let me try to break all that down and do it
Thanks for the info I’m just trying to not have my brain explode rn
Is 3 just 2pi/45 rpm then?
On the first page
Is this right for those two?
@viscid thistle
The second one is not
And the first one must be expressed in rad/s not in rpm
For the second one look better at the formula
Its $V=\omega\cdot r$ not the other one
Al𝟛dium:
Wait what did I do wrong then in the second
Its $V=\omega\cdot r$ not the other one
Al𝟛dium:
Yeah cause w=2pi/45
I multiplied that by 125/1
Neither the dots
No worries
So yeah its correct
And the first one must be expressed in rad/s not in rpm
@viscid thistle dont forget this one thing tho
Wait it says radians per minute though so wouldn’t it be rad/m not rad/s?
(I put rpm and derp, that’s revolutions per minute not radians per minute lol)
Wait it says radians per minute though so wouldn’t it be rad/m not rad/s?
@gloomy mortar you are given 45s
Not minutes
Therefore it must be seconds
So rad/s
Or whatever notation that its equivalent to that
Yeah but it says calculate in radians per minute which I just now realized
Unless that’s a typo
Where?
Right on number 3
So just times it by 60?
Look
I mean to get rad/s to rad/min do I times 2pi/45 by 60?
,ask (2pi rad)/45s to rpm
^
It’s not rpm it’s radians per minute
BRUH oml i need to eat urgently lol
Lol
I mean to get rad/s to rad/min do I times 2pi/45 by 60?
@gloomy mortar yeah
Totally correct
So I’m taking a look at the last two pages, and I have this so far. I feel like I should use the sines law, but with the info I have I’m confused...
Cause I have sides b and c but angle A...
If I use the Cosines law I get stuck
Yah for the tree one you gotta use cosine law
It has 3 forms
Use the most convenient one @gloomy mortar
Wait so I don’t need that to be angle A then
Does it matter what’s angle A, B, and C?
it is opposite to side
I mean does it matter if that is angle A, B, or C?
Yeah
Because it doesn’t say what side is a, b, or c
You can just name them
But respect the angle
Like if you put angle A, the side a must be on the opposite
Okay I still don’t get what I use though. Because the different versions of the cosine law only have one version for each angle
Okay
For this one i'll tell you
Just so you get used to it
$$a²=b²+c²-2bc\cdot \cos(A)$$ so $$a²=30²+45²-2(30)(45) \cdot \cos(86)$$
Thats it
Al𝟛dium:
Oh wait wait yeah I know what to plug in for that but I still don’t get the info I need I mean
I need angle C
Al𝟛dium:
Bc now you know a, b and c
😳 I didn’t think of that
I’m confusing myself
I feel like I need to take cos^-1 to cancel cosine and find <C but how do I do that here
Cause I can’t find cos^-1(4.07)
@viscid thistle
4.07 = cos(C)
Yeah
the fact that you got cos(something) to be a value above 1 is
kinda suspicious ngl
hoooold up
What did I do wrong then I’m confusing myself
,calc 2 * 52.31 * 30
Result:
3138.6
,calc 52.31^2 + 30^2
Result:
3636.3361
so you had 2025 = 3636.3361 - 3138.6cos(C)
that's what you should've had, anyway
and then you... subtracted the 3636.3361 and the 3138.6?
yeah, that's where you went wrong
No that’s the same number
497.7361
2025=497.7361cos(C)
That’s what I have
,calc 3636.3361 - 3138.6
Result:
497.7361
Result:
4.066265060241
,calc 2025/497.7361
Result:
4.0684209965884
4.07, approximately
,calc 30^2+45^2-[(2(30)(45)*cos(86)]
The following error occured while calculating:
Error: Parenthesis ) expected (char 30)
,w range cos(x)
,calc 30^2+45^2-((2(30)(45)*cos(86))
,calc 30^2+45^2-(2(30)(45)*cos(86))
The following error occured while calculating:
Error: Parenthesis ) expected (char 31)
Result:
3960.9858013643
,calc sqrt(3960.9858)
Result:
62.936363097974
Look
@gloomy mortar you are making an algebraic fuckup
to demonstrate...
by your logic, the equation 35 = 50 - 2x would have x = 35/48 as a solution
which it does not
3636.3361 - 3138.6 * cos(C) is not (3636.3361 - 3138.6) * cos(C)
I used a calculator for that too
@gloomy mortar redo it
mythicalsheep
I just did
i am not saying you did your arithmetic incorrectly
And got the same answer
i am saying THAT THIS IS AN INVALID ALGEBRAIC MOVE
Wdym Ann
ok so like
can you show your work again
redone if possible
so that i can pinpoint the mistake more easily
redone
Ik
Why’d you subtract 2025 and put everything over 3138.6
That’s the opposite
aight so like
you know what really is not helping
the fact that you're choosing to work with big messy numbers
Why’d you subtract 2025 and put everything over 3138.6
because
a^2=b^2+c^2-2ab(cosC)
I’m using the scientific calculator to make my life easier so I don’t have to work with them
algebra
sometimes it can be easier to make everything a variable, then put numbers in at the end
$c^2 = a^2 + b^2 - 2ab \cos(C)$ can be rearranged as-is to $\cos(C) = \frac{a^2 + b^2 - c^2}{2ab}$
Ann:
sometimes it can be easier to make everything a variable, then put numbers in at the end
@remote veldt always lmao
^
I mean like with coefficients of 1 or whatever it usually doesn't matter lmao
also avoids round off errors
I literally did that I just didn’t put that equation in my work
To the equation yes
and subtracted things that weren't meant to be subtracted.
,calc 252.3130
Result:
3138.6
$c^2 = a^2 + b^2 - 2ab \cos(C)$ can be rearranged as-is, \textbf{without plugging anything into anything}, to $\cos(C) = \frac{a^2 + b^2 - c^2}{2ab}$
Ann:
To the equation yes
@gloomy mortar that led to algebraic messings
wtf
a²=b²+c²-2bc•cos(A)
That’s the first part
I did exactly that
Commander that was me dividing it on both sides to cancel it out
where from 497
I already explained and calculated
Better $a=\sqrt{b²+c²-2bc\cdot \cos(A)}$
The whole equation before cos(C)

Al3dium I did nothing different
Al𝟛dium:
Look
Yeah I know
why have you already plugged numbers in mythical sheep. Why are there numbers in front of the cos(x)? why are there numbers anywhere?
this is the issue that ann was stating
$a^2=b^2+c^2-2ab\cos A$
You guys are ignoring what I said
Those are the values plugged into that equation
The first one
Commander Vimes:
The one with cos(A)
yes
do not plug values in directly
A = C now
wait
I know the equation
Commander Vimes:
if you wish so
I did that for the second one
Look at the triangle
That’s where the values come from
I found 52.31 in the first equation
$c^2=a^2+b^2-2ab\cos C$ hence \
$2ab\cos C = a^2+b^2-c^2$
$\cos(C) = \frac{a^2 + b^2 - c^2}{2ab}$
Al𝟛dium:
Just redo it
I already know the equations
Commander Vimes:
AlKhashi's
I did and you guys won’t believe me
theorem
Commander Vimes:
4.07
you did $\
\cos C = \frac{c^2}{a^2+b^2-2ab}$
Commander Vimes:
,calc arccos((52.31^2+30^2-45^2)/(251.3130))
use arccos
and wolfram
The following error occured while calculating:
Error: (intermediate value)(intermediate value)(intermediate value) is not a function
,w
Please submit a valid query! For example, ,ask differentiate x+y^2 with respect to x.
That’s not the equation
^
Stop talking
This is what I did
The equation in red is what I did
Which is what I was told to do
The following error occured while calculating:
Error: Syntax error in part "²+30²" (char 6)
^2
Result:
3741.9561
,calc -2(52.31)(30)
Result:
-3138.6
52.31 btw
Result:
3636.3361
,calc 3636.3361-3138.6
Result:
497.7361
Yep
2025=3636.3361-3138.6cosC
You didn't respect the order of operations
What
I did them originally but I mistyped it so I had to recalculate
are 3633 and 3138cosC similar terms of the equation?
can you add bananas to chairs?
meh
@gloomy mortar The point I have been making is that your fundamental error came in in this step (red arrow). Do you understand why I say that you shouldn't have done that
Everything is plugged in the exact same as the equation
yes. But you should not be plugging in anything that early
you should isolate for the variable, and THEN plug in
AND ANYWAY
you made algebraic errors because there were numbers there
are 3633 and 3138cosC similar terms of the equation?
@harsh smelt
you subtracted non-similar terms, for example
isolate first
before there are ANY numbers
and then plug in
can i add bananas and chairs?
it will minimize these silly algebraic errors
yes. But you should not be plugging in anything that early
Exactly, which is what everyone has been telling you @gloomy mortar
The equation is c²=a²+b²-2ab•cosC
advantages of operating with symbols:
easier to read
easier to parse
mimnal round-off-errors
The equation is c²=a²+b²-2ab•cosC
yes
we need cosC
I plugged into that because that’s the equation I was given
...
and we are saying to wait to plug in until AFTER you have isolated for the thing you want
right now, that equation has c^2 isolated
manipulate it until the isolated thing is C (or cos(C) if you prefer)
or. at least AcosC
Okay well I wasn’t told that at the start I went with the equations I was given
I literally barely even know how this works how am I supposed to know not to plug it in from the start
