#help-36
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would qpr be 76?
That would imply SPR is a straight angle
so probably not
I'd maybe just do law of sines
sin rule?
sin(QPR) / 200 = sin(45) / whatever you calculate PR to be
Can you find QPR from there?
yeah
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$-7|x + 12| \leq -14$
BabaEagle
Have you done similar problems before?
yea but im confuised
i divided by -7 and flipped the symbol
then i wrote
-2 ≥ x+12 ≥ 2
is this correct?
no
y
Don't skip steps
don't take shortcuts
by writing that there's an implementation that -2 is greater than 2, which it is not
still wrong
how do i do this
after dividing you'll have
$$|x+12| \geq 2$$
ℝamonov
and then if you don't know the identity for the shortcut, go the long route and consider the negative and positive cases
what does that mean
do case work
case 1: x+12 >= 0,
what will the equation be under those conditions
similarly,
case 2: x + 12 < 0
what will the equation be under those conditions
(note that that's actually a bit overkill)
how do you know to switch the symbol
which symbol
greater than and less than
when you do stuff like multiply or divide both sides by a negative value
consider doing the long case work, or properties of absolute values, geometric interpretation or identities
probably
ok ty
good vids on absolute value inequalities should tell you the process behind reaching that
consider some simpler examples like
|x| >= 5
and
|x| <= 5
how they're different and how they'd be represented on the number line
note that though what they've written in the solutions is what you should have
(i don't know whether you had that yourself)
you can not represent it as
-2 ≥ x+12 ≥ 2
-2 < |x+13 | < 2
and it said it was correct
and i didnt have to switch any symbols
you mean -2 < x+13 < 2 ?
yea
and i got -15 < x < -11
(-15,11)
and it said ok
this is why i am confused
it'd be clearer when you|
consider some simpler examples like
|x| >= 5
and
|x| <= 5
how they're different and how they'd be represented on the number line
yea
were you able to do those simpler examples?
both are wrong
why
|a| > b does not mean a>b or a>-b
likewise
|a| < b does not mean a<b or a<-b
oh ok i see
i just read my notes my teacher told me
keep the first one same sign and symbol
then flip the symbol and sign
so x less than a
x greater than -a
geometrically the solutions to |x| >= 5
are the values that have a distance greater or equal to 5 from 0
geometrically the solutions to |x| <= 5
are the values that have a distance less than or equal to 5 from 0
what do u think about what i mentioned
sounds wrong
also not ideal if you don't understand the theory behind what you're doing
geometrically the solutions to |x| >= 5
are the values that have a distance greater or equal to 5 from 0
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how would I solve for G? I was told to make a parallel line in between both lines to find exterior angles but i dont quite understand. some help would be much appreciated. https://media.discordapp.net/attachments/426033723448885248/1019064280710139974/IMG_4019.jpg?width=683&height=910
apply some parallel line theorems
we werent taught that yet
we briefly went over it in class for like a minute or so and he didnt really tell us what it was but rather he just showed us
google parallel line theorems
and read up on them
it'll give you a clearer idea of what to do here
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how do you characterize by abstraction?
e.g. Characterize the following set by abstraction: {11, 121, 1331, 14641}
@south aurora Has your question been resolved?
,wolf 11^2
,wolf 11^3
,wolf 11^4
i understand the math, but how do i characterize it in terms of {x, y}?
like {11^x} and then something else for y?
we are doing set theory right now so i think along the lines of that maybe
maybe {0<x<4, y=11^x}?
look up set builder notation
first the object, then the contraints
{11^x|x integer & 0 < x < 5}
okay thank you!
i have one last question, could someone help with this please? Prove that there is at most one empty set (i.e., that if A and B are sets with no members, then A=B).
Hint: What is the usual way to prove two sets are equal?
I have this in my notes: 1.) Suppose A is a a subset of B. Take arbitrary object x and suppose X belongs to B. Then X belongs to B. Suppose now X belongs to B then X belongs to A. So X belongs to A iff X belongs to B. So A=B. 2.) Suppose A=B. Then A is a subset of B. Similarly, B is a subset of A
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@hasty egret Has your question been resolved?
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@hasty egret i can help you if you still require it
.close
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Yes that would be awesome. Please
right, so we can use the variation formula which is as follows
what even was the problem
it got deleted...
rip
@hasty egret repost
yep
basically you just take a bound and show the variance is less than 40 for all naturals > 1
nic
could you please elaborate more? @pine root
ok wait no sorry the answer is a lot more complicated than that
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plz help
we did this over a week ago and now we have our review and tset tmr
and im completely lost
you need to calculate x and y components of u, v and w
get actual vector form and just add them yeah
and then for the angle ik its tan but of everything individual or together
okok lemme do it rq
ok so for the final x i got -54.82
and y i got 18.53
so the hypotenuse is
55.03
close enough to 57 right?
but for the angle i got -71
what did i go wrong
oh nvm
cause im supposed to subtract form 90
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I apologize for asking again but when converting absolute value into piece wise when do we use the >= or <= signs?
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@jolly eagle Has your question been resolved?
ultimately its not gonna matter, i believe
like
\begin{equation*}
|x| =
\begin{cases}
x & x \leq 0 \
-x & x > 0
\end{cases}
\end{equation*}

jan Niku
thought exercise is to think of like
what happens if you move the equals case from x to -x
hint: whats |0|?
|0| = 0 = -0
@jolly eagle
i see so the sign doesnt really matter because it would work either way?
well its just like
-x and x agree at a place
its where x=0
so then the equality can be shifted between the two in that way
because the equals case in piecewise absolute value is always where the argument equals 0
its sort a special quirk of |x| i guess, or just uhh
i believe this is just a part of functions that are symmetric about 0
so you could say even functions in general

hm ok cool thank you I think I understand it a bit better now
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hello I need help in inequalities
@eager galleon Has your question been resolved?
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,rotate
you can think of it as combination of two different situations
P(white or yellow, in either order but not both) = p(white first then yellow) + p(yellow first then white). it might be easier to calculate it in that way
Which is 1/10 x 2/9 + 2/10 x 1/9?
@misty sky Has your question been resolved?
wait you still confused? 1/10 x 2/9 + 2/10 x 1/9=2/45 is the answer isn't it?
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Given F: R^4 -> R^3
if I have a basis of ImF as {( 1, 0, 1), (0, 1, -1)}
How do I find the set of values associated with F^(-1)[( 1 0 1)]
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Given F: R^4 -> R^3
if I have a basis of ImF as {( 1, 0, 1), (0, 1, -1)}
How do I find the set of values associated with F^(-1)[( 1 0 1)]
This is the linear map
<@&286206848099549185>
<@&286206848099549185>
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<@&286206848099549185>
.close
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Hi i need help for this one
at Jay's pizzeria a pizza cost $5 with the first topping, and then an additional 75 cents for each additional topping
if x represents the number of toppings on a pizza, what function represents the cost of pizza with atleast one topping?
So the initial price is $5 and every additional topping cost $0.75. If we have x additional toppings can you think of a way to express this.
That's the question reworded 😭
I think the wording is a bit confusing
You must have 5 at first so the function is gonna be 5 + something that depends on how many additional toppings you want.
5 +.75x should work yeah?
sorry
5+.75(x-1)
as 5 is the initial cost, with you only adding.75 if there is more than one topping, which is where the x-1 comes from
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after proving that f(x) = x/(1+abs(x)) is indeed bijective, i was asked to find its inverse function f-1(x)
i found two values
f-1(x) = x/(1+x)
f-1(x) = x/(1-x)
is this possible?
be careful about |x|, what if x < 0 and what if x >= 0?
yes thats what i did
and from those two cases i got two expressions of f-1(x)
also f-1(x) goes from ]-1;1[ to IR
so one of them is for x < 0 and the another for x >= 0
yes, kind of
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what's the domain
of
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tan(2arctan(x))
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whats the answer to the problem
You are given values of a,b,c right
So substitute it in the question
Hmm?
Well in the question it is asked $-(27^2)$
And not $(-27)^2$
yuck
Omg not again
if you square -27
your colours 🤢
wouldnt it become postive?
Yes it will
the square is done before the negative sign
so my teacher is wrong
But thats not what it’s asked here
we do the exponents before we do the signs in front
,w |abc - 27^2 + 6b| where a = 9, b = 4, c = -8
Yes he/she is for 288
,w -2^2
,w -27^2
HOW
like
ask wolfram
no no
because in math notation
Refer here
the exponent is applied before the negative sign
thats just convention
if you want the negative sign included you need brackets
thanks deep
\lettern\letterp
Please give me something to compile, for example latex ,tex The solutions to \(x^2 = 1\) are \(x = \pm 1\).See ,help and ,help tex for detailed usage and further examples!

okay oka
oh no i cant even remove that
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thanks nerds
Np

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Whats the relevance of ‘exactly 2 days’ in question 2b?
How does it relate
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M
@rugged idol Cannot see any problem here.
Oh ok, now I can.
Okay so now what you have to do is start by taking certain x values and plugging them in to find the y's and graph.
So cause there is -4 there already in the middle as the key term.
Maybe before that you can do -2 and -2.
And after that do 0,1, and 2.
The -4 is wrong
Okay, then why is it there?
Cus ididnt erase it yet
Oh okay, got you.
Then do so, and you can use the following values as the x and find the y values to evaluate.
x = -2,-1,0,1,2,and 3.
Then plug those in and solve and tell me what you get it. I will do it on my side as well.
@rugged idol Are you doing it?
Okay, keep going.
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Im not sure how to approach this
Im not sure what to do first
Like i said, start expanding and simplify the numerator
You will notice that you can further simplify the fractions after that
.close
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How do I “expand this”
@hushed fable Has your question been resolved?
this is just (a+b)^2 from algebra
it looks like you're trying to find the derivative of f(x)=x^2 where x=-1
$f'(-1) = \lim_{h\to 0}\frac{f(-1+h) - f(-1)}h = \lim_{h\to 0}\frac{(-1+h)^2-(-1)^2}h$
is this where you are?
rome of oxtrot
if this is whre you are, the next step is to expand the $(-1+h)^2$ term using binomial expansion
rome of oxtrot
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is this correct?
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Sorry but is this the right derivative to my problem
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Heyo, I am struggling to figure out how to prove the cardinality of the set of prime numbers is equal to the cardinality of the set of even numbers, I don't really know where to start as unlike even numbers to odd numbers I can't just directly map one to the other. Is anyone able to give me a bit of a hint on how I can do this, or perhaps a link to a source that explains it a bit?
@brisk otter Has your question been resolved?
<@&286206848099549185> Sorry is there anyone who can help me with this one?
Let f(p)=#{n in P|n<p}
What is the #?
oh right
this is quite literally just another way of saying f(p_n) maps to n where p_n is nth prime
but mire explciitly showing that its a bijection
I understand what you're saying but not entirely how it works
so how does that show it's a bijection? Or more importantly, how do I use that against even numbers
test it out with a few primes
alrighty 😛
i mapped the primes to the nsturals
im sure u know a bijection between the naturals and the evens
yes okay
compose them
depending if u jnclude 0 in N or not, you may with ti replace the n<p with n<=p
I do not include 0, thank you though
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Hey there,
I have 3 sets
U={2,3,4,5,6,7,8,9,10,11,12,13,14}
A={1,3,5,7,9...} | These are infinite odd numbers
A'={2,4,6,8,10,12,14}
If I get asked something like
Does A∪A' = U? Is it true or false. I'm stuck because A is infinite
Thanks
You should use ... notation to indicate that a set is infinite (just now realised that this is irrelevant)
U doesn't have 1 in it, but A∪A' does
So no
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Can someone double check the last one wolfram says it should be diagonalisable but it doesnt work
,rotate
are u multpiplying
Matrix multiplication
Doing the last two first leaving the left most
i forgot u have to add them 1 sec ill check it
yeah that looks right
which row is wolfram alpha saying is wrong
Wolfram says it is diagonisable
Meaning it should give the ? Relation
But i get some other matrix
yeah sorry my knowledge of linear algebra only extends to multiplying matrices not diagonisable
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any tips on solving this without l'hopital's rule?
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is this reasoning incorrect:
i think there might be a =0 missing in the statement
correct.
this is what i came up with for the problem: as p is not a perfect cube, p^1/3 is irrational, therefore for b, c ∈ Q\0, b(p^1/3) and c(p^2/3) is irrational. as a+b(p^1/3)+c(p^2/3) =0 as RHS∈Q and rational numbers are closed for addition, LHS is also rational, therefore b(p^1/3) and c(p^2/3) are also rational. b=c=0 and a+0+0=0 therefore a=b=c=0.
im an idiot tho which is why im asking to see if this is incorrect lol tho thx
LHS is also rational
seems ok up to here
therefore b(p^1/3) and c(p^2/3) are also rational.
but then this is bad
aha
there is no such things along the lines of the converse of closure of rational numbers under addition i.e if a,r∈Q, a+b+c=r then b and c not nessecarily ∈ Q? or im misunderstanding why that is wrong
thanks btw!
wait no im confused. if the LHS i,e a+b(p^1/3)+c(p^2/3) and a is rational then b(p^1/3)+c(p^2/3) must be too. (-a is rational). doesnt this mean both the numbers are rational as the sum of an irrational and rational is irrational and the sum of an irrational and irrational is irrational? therefore both terms must be rational and b=0, c=0.
is this incorrect?
@vapid crystal Has your question been resolved?
sum of two irrationnals can be rationnal, example, pi + (1-pi)
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oh yea that makes sense lol thanks!
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Where do I start if I’m trying to solve this by eliminating X first
put the equation that begins with -x on the top for convenience
add suitable multiples of this equation to the other two in order to make the x-terms in those cancel out
and you will have your x eliminated
two equations in y and z
which you can solve
and then recover x
So add multiples to this?
add multiples of (-x+2y+5z=-21) to those two, yes.
ok if i just told you to add that equation itself to each of these
would you understand what i meant
Yea
ok
and if i told you for example to add 4 times (-x+2y+5z=-21) to (4x+2y-3z=10), would you understand what i meant?
congratulations on completely missing my point!
no, that is not what i said to do.
what i said is to multiply (-x+2y+5z=-21) by 4 and add THAT to (4x+2y-3z=10).
@pearl jewel Has your question been resolved?
@tired walrus uhh hello.
alright yeah
now you have 2 equations in y and z
you've eliminated x just as you wanted
What would be the next step
well do you know how to solve systems of equations in two variables?
Is that where you eliminate by addition
??
Never mind, let’s go with No
So now that I have (10y+17z=-74) and (23y+35z=162) what would I do.
@tired walrus 🧍🏿♂️
this is a system of two linear equations in two variables
with some kinda nasty numbers
i would go ahead and power through the arithmetic and do this:
10y + 17z = -24 | * 23
23y + 35z = 162 | * (-10)
- Write in standard form then solve for y on one eqn and substitute its value for another
- Multiply both eqn by diffrent numbers such that y coefficents are equal and cancels out leaving the lone variable[z]
choose option [1] or [2]
on the basis of difficult and difficulty only
yes, it's short for "multiply both sides of this equation by this number"
in terms of pramad's classification up there my digression is option 2
yes
either one
it doesnt matter
...forgive me for the rashness but it sounds like you have ZERO experience in solving systems of equations in general
youre asking questions that would sound obvious to someone who understands what a system of equations really is
Yea we went over it for no more than 15min and the professor gave us this problem to solve for extra credit.
okay so your prof threw you directly into the deep end of the pool is what you're sayin
saying*
on the FIRST DAY you're learning about systems of equations.
that explains it
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can someone help please?
I assume you are unable to help
yes sir
@tranquil pine Has your question been resolved?
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Here's the original problem:
"From two cities, distance between being 800 km, two trains start travelling towards one-another, and they meet 8 hours after start. If the first starts 3 hours and 20 minutes earlier than the second, they will meet 6 hours after the second train starts. Find the velocity of the faster train."
I'm at systems of linear equations
ok so I got x+y=100
S = v * t
S distance, velocity, time
800 = v * 8
v = 100
so x+y=100
then it's 6y=800
but how do I put x
in terms of x being the first train that starts 3 hours and 20 minutes earlier
my textbook says 4 hours and 20 minutes earlier = 37/3
I'm incredibly confused how 4 hours and 20 minutes earlier becomes 37/3
or 12 1/3
@feral cobalt Has your question been resolved?
hi! I can try to help.
ok so look, I have to go
I will look into this when I get home
if you could, DM
or w/e is more comfortable for you
I'm calling this a day
buh-bye for a few hours
gonna let this close due to timeout
ok! I'll let you know later!
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use the d = rt
there are two ways to go about it.
- either you use relative speed (the distance between the gap) or you solve them individually.
@tranquil pine Has your question been resolved?
look, I know
just read
im tired
tnx
the convention ratio is always equal to one. ie. 1hour = 60minutes can be written as 1hour/60minutes. Now the clock time is 4hour + 20minutes, so we multiply by ratio 1/60 so we get 4+ 20*(1/60)= 4+ 20/60 = 4 + 1/3 we all know 1/3 = 0.333 hence the time = 4.333
you can also do it like this
find the lcm: 12
(12x4)/12 + 4/12 = (48+4)/12=52/12 now remove a factor of 4 = 13/3hrs
I'm very tired and it's late
I will read up tomorrow
close thread if you will
thank you!
I am interested in the answer, but good night.
will DM you tomorrow
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Hey guys I need help on my hw I can't seem to figure out how to get the fraction for E can anyone help
B could be any decimal less than less but greater than 0. however, B is greater than A and C.
E could be any decimal number between greater than 2 but less than 3.
ur right with guessing b is 0.5
i dont think they want it that precise man
its a number line
e is in the middle of 2 and 3
there is are infinite number between them
so what is the number halfway between 2 and 3
yes but this is too complicated
the question said could.
She need to estimate.
so its D?
well done
exactly and 0.5 * 2.5 is 1.25 which is d
ohhh ok thank you guys so much
that wasn't that hard idk why I have trouble with this types of things
Sometimes the diagrams caan be tricky.
to be safe test extreme case.
nah dw
yeah but its a number line man
not like some complex roots of unity argand diagram
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Normally simple questions are the trickiest
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Can someone help me with part b? I know to isolate so that z = 0, but idk how to ... apply that
projection just means ignore the z part, so just describe <tsqrt(1-t^2),t^2>
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NPV for population 1 is 0% as everyone in population 1 has a certain disease
NPV for population 2 is 100% as no one has the disease
ok
your a blesssing

help me one last time my goober bro
mm u have to make a table for both of em
has disease no disease
test positive ur values ur values
test negative ur values ur values
like this
straight forward
is the / as in you divide them
yuh
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Can someone explain the difference between part a and c
am I blacklisted
nah u aint, the velocity vector isnt the equation of the tangent line
tangent line is 1D function of x, velocity vector is 2D function of t_0
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Hey, I have a question regarding composition of functions.
Consider functions f and g such that f of g = sqrt(x^2 + 1) - 1. If g(x) = x^2 + 1, then what's the value of f(4)?
So, f(x^2 + 1) = sqrt((x^2 + 1)^2 + 1) - 1)
x^2 + 1 = 4 ... x = sqrt(3)
Then, sqrt(17) - 1. But, the answer is 4.
I don't see what I did wrong?
i think you're misunderstanding the notation a little
you claim to be looking at f(x^2+1), however the only function you have at the moment is f(g(x))
you first need to extract the function f, and only then can you look at trying to evaluate f(4)
@loud gust
@marsh temple But, if you plug in sqrt(3), you get f(4)?
plug in sqrt(3) into what?
i mean sure, if you plug in sqrt(3) into g then you get 4
but you don't know what f is
I think the crux of your issue lies in this line
So, f(x^2 + 1) = sqrt((x^2 + 1)^2 + 1) - 1)
f(g(x)) = sqrt(x^2+1)-1
However, g(x) = x^2+1. If we sub this into the left-hand side of the original equation, we get:
f(x^2+1) = sqrt(x^2+1)-1
or, if it's more readable, f(g(x)) = sqrt(g(x))-1
I just don't understand why if you have f(g(x)) = sqrt(x^2 + 1) - 1 that you can't just set g(x) = x^2 + 1 such that f(x^2 + 1)) = sqrt((x^2 + 1)^2 + 1) - 1 so that you have function f by itself.
Then you can just set x^2 + 1 = 4 and get sqrt(3). Then, f((sqrt(3))^2 + 1) = f(4) = sqrt((3 + 1)^2 + 1) - 1 = sqrt(16 + 1) - 1.
you're making two different substitutions
in the equation:
f(g(x)) = sqrt(x^2+1)-1
there is no g(x) on the right hand side
what you're doing is making the substitution x = x^2+1
Yes, but if g(x) = x^2 + 1, shouldn't x = x^2 + 1 as seen here f(x^2 + 1)?
again, that's two separate substitutions
in the first case, you're replacing g(x) with its definition
however, x and g(x) are not the same object, and thus you can't make the same adjustment and say that they're equal
@marsh temple I think I see now. I'm just replacing g(x) with x^2 + 1, but I'm not constructing a new function. The function is already given. So, f(x^2 + 1) = sqrt(x^2 + 1) - 1 and then I'm able to plug in sqrt(3) to get 1.
if that helps you think about it, sure
the main takeaway should be that saying g(x) = x^2+1 is not the same thing as saying x = x^2+1
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Have you got a diagram?
I have no idea about 1 but for number 2 yes I drew the triangle diagram
It’s like an angle measurement but starts from north
North is 0 degrees
Then go clockwise
160
ohh that makes sense
Yeah so 160 is between south and east
what about the 2 cm long part
I think that’s just using a ruler
Alright
I’ve honestly never seen W60S before
No idea what it means
Maybe that means 60 degrees below west?
well north is 0 and 360
I think it means between west and south
and 60 degrees below west
So 210 degrees
But I could be wrong and it’s the other way around
So 60 to the right of south
240 degrees
For b can we send me the sketch?
I’m in a bath rn lol
Give me a sec I’ll try to draw something
no
Or 310
that s single vector
a
den u add the other vector
80kmh from the easr
east
and create a triangle with it
yes but theres problem
the wind is coming from the east
Oh
so that means its going west
Damn it
the bath distracting you lol
Here we go
yes
Then cosine rule apply heee
$$ R^2 = 80^2 + 450^2 -2(80)(450)\cos(40)$$
Pure
since i saw east as a stright line i thought it was 90
so 90 plus 40 would give me 130
but yea its just 40 because the 80 doesnt have an angle
is that a 90?
why
we only need the inside angle
im lost lol
ohhh
No the z pattern doesn’t apply here
it can
here ill show you
i said 90 because the looks like a right angle
so 90 plus 40 = 130
I think it’s 210 bearing
ok thanks
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Ok
E=mc2
huh?
?
amazing
Lol
how did u derive that
yea how did u find out
just appeared to them like Kubla Khan 😂
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help pls
what is the probability that a player gets one of the duplicates? what about getting the other too?
wouldnt that be (13/52)^2?
close but no. lets say we have two cards labelled 1a and 1b. what is the probability that a specific player has card .1a ? 13/52. what about card 1b too? 12/51 (12 cards other than 1a from a deck containing card 51 cards). for 4 players p(a a player has both duplicates)= 4*13/52*12/51=12/51
youre neglecting to acknowledge that receiving one duplicate removes one card from the deck and one spot to receive the other duplicate for a player
this can also be also thought as follows: a player must receive one of the duplicates because every card must be given away. this reduces the deck size by 1 and the spots of the player by 1. so 13-1/52-1=12/51
ahhh true, but why multiply it by 4 if its for one person
because this is the probability for one specific player, say player 1. but there are 4 players.
any of the 4 players can receive the two duplicates
so wait like combinations?
4C1?
P(ANY player has two duplicates) = P(p1 has two duplicates) + P(p2 has two duplicates) + P(p3 has two duplicates) + P(p4 has two duplicates)
what is P(px has two duplicates) = P(px has duplicate 1) * P(px has duplicate 2) = 13/52 * 12/51
P(ANY player has two duplicates) = 13/52* 12/51 + 13/52* 12/51 + 13/52*12/51 +13/52*12/51
no problem!
@autumn siren Has your question been resolved?
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Hello, I was going over polar coordinates and it seems to me that the difference between the argument and principal argument is that the argument has an infinite number of values whereas the principal argument is confined to -π to π. The reason I think this is because it would explain the following diagrams which show that the argument is always between -π to π.
- But if this is the case my question is why do we restrict the interval of the principal argument to -π to π?
- Also why do we convert from cartesian to polar coordinates? In what cases are polar coordinates better?
(I think this is to represent events where objects move in circular paths but if there are other reasons I would like to hear about them)
Thanks!
principal argument is just defined to be in that interval, nothing more. However, there is no such thing as a principal argument in polar coordinates, there is just r and theta, and theta, in a way, has no restrictions
the point (1, 1) for example can be represented as (sqrt(2), pi/4) or (sqrt(2), 9pi/4) whichever you want
you are most probably referring to the argument of a complex number here
oh so for polar coordinates we care about the argument θ instead of the principal argument?
yes that's what I was currently reading 👍
no, we really do not, we just only care about what is the angle between the positive axis and that number, that's all, argument in polar coordinates does not matter that much since they dont really give us much use
does argument help us convert between polar coordinates to cartesian coordinates?
when representing complex numbers, we are drawing vectors and stuff a lot more, so that's why we talk about arguments of complex numbers
for polar coordinates, we just use it as a tool to draw curves that are way to complicated to represent with just x and y
not just that, but also it acts as a way to simplify the way we can represent a curve. For example take the circle x^2+y^2=1, and i just want to find some random points on this circle, say the point that is pi/2 from the positive x-axis. This is gonna take me some arithmetic to do, subbing in values and stuff, it's tiring. By using polar coordinates, the equation of this circle becomes r=1, this basically means my set of points has the radius of 1 from the origin, and the angle that it makes with the positive x-axis is any angles i like. So that means the point that is pi/2 radians away from the positive x-axis is (0, 1)
this is probably the simplest example i can find that make use of polar coordinates. And as you see, it barely uses the concept of "argument"
theta is just an angle at the end of the day
there are more beautiful curves than just circles, for example the rose curve or limacon, you can check it out online if you want
these curves definitely are not very nice when written in terms of y and x
thanks for the example, its good to know that polar coordinates makes calculations and equations simpler
ill check these out
Thanks for taking the time to explain this, Waler!
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np
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in this integral, when you do u = 1/x and du = -1/x^2dx
how do you include the negative when 1/x^2 here is positive?
du = -1/x² dx right?
If I remember correctly, when you 'add' a value, you needed to divide by it on the outside of the integral


