#help-13
1 messages · Page 251 of 1
You want to find the line l
So you need a point and a vector
Q is in l so you already have a point
Yes
And l is perpendicular to π, so n is the vector
Yes okay
So you can find l
Now, if l is a line that contains Q and is orthogonal to π, what is the orthogonal projection of Q onto π?
N - Q?
Why?
Well I don’t know I am just guessing
Do you know what the orthogonal projection is?
No
Then you should study and understand it before trying to do a problem about it
You should at least know a formula to find it or something
Otherwise you can't do anything
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This is so confusing, idk where to start
lets start somewhere
do you know when f(x) is negative? Or when f(x) is positive?
Put the values
Positive when x= 0 and 7, negative when x = 4
No expansion
Ok
No, in general.
Oh uhh
i suggest graphing out the equation
To find signs
This is a dsat question, I can use desmos
Damn...
the x^2 coefficient is >0, so the graph should be u-shaped
But there is x
and since at x=1 and x=7 f(x) is positive, the minimum of the graph should be between 1-7
that should be your first clue
👍
Does that give me anything?
We need a + b
Of course
a rough sketch of the graph
Graph is difficult
I mean table of signs
Method of intervals or whatever
heres another hint: the equation is under the form (x-a)(x-b), therefore a and b are the 2 roots of the equation
essentially, you are finding the possible sum of the two roots
Ok can someone tell me steap by step what to do? I'll really confused
Ok I gotta go, I'll just ask my teacher tomorrow
Sorry
Thank you everyone
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I figured out
4<a<7
1<b<4
@crimson sedge
You just have to put value of x inside function
We need just one value a+b not exact value
We can assume a and b by these interval
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hi
sorry im a freshman taking calc 1 and im a bit unfamiliar with the general terms of integrals
i know that the integral of any variable ie x^n is x^n+1 / (n+1)
but the symbols here got me confused as im new to them
$\int dx = \int 1 dx$
Xotiic
makes sense but what exactly is dx here
im familiar with the derivative notations
to tell you what you are integrating
but im completely oblivious to how they work in this context
Yh it tells you what you’re integrating with respect to
so if u were saying
if it said dk you would be integrating k in this integral
dx is not the derivative of x.
yeah wrong use of words
dx is a differential, the derivative of x is 1
so if u were to turn the first note into words
what would it read as
the integral of any constant is x+c?
no
integral of 13 dx would be 13x + c
think of it as k*x^0 and use the power rule
well as the other person says its just the integral of 1 dx
or the integral of 1 * x^0 dx
yes what does that exactly mean
ohhh
if you see a constant term just remember theres and x^0 in there
well whats the power rule?
is it just talking about the variable x raised to any power
yes
yeah i get it now
im familiar with the technicalities but i was just confused with the official formula bc its been a while since i last took integral calc 😭
anyways ty
but you will learn about that in the future
wouldnt that be
like
oh i see where this is going
(u cant divide by 0 so u cant use the power rule for this)
yeah this is all we took
oh yeah its just number 5
figured 😭
i have an exam this saturday with the basics of integration and the fundemental theory of calculus
wish me luck
good luck lol
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Hey
I need to transalte this
for what $a$ is vector u and v paralell if $\vec{u}=(-2,a+1,-4)$ and $v=(a,-1,2)$.
Totalani
what I did was $(-2,a+1,-4)=\lambda(a,-1,2)$
Totalani
Which gave me $$\begin{cases}
a\lambda=-2 \
-\lambda=a+1 \
2\lambda=-4
\end{cases}$$
Totalani
Kinda stuck here, not sure if I did it correcly up to now?
nvm think I got it
yup I got it
.closer
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Find the square of:
3a-2b-5c
How did -2b become +2b
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R = {(1,3),(1,5),(2,3),(2,5),(3,5),(4,5)}
Is R^-1 = {(y,x) | (x,y) belongs to R}?
yeah
Are you trying to expand a trinomial?
Alright, so
R⁻¹ = {(3,1),(5,1),(3,2),(5,2),(5,3),(5,4)}
R○R⁻¹ = {(1,1),(1,2),(1,3),(1,4),(2,1),(2,2),(2,3),(2,4),(3,1),(3,2),(3,3),(4,4)??? but this is not even in options
oh it ended
what does ○ mean?
Composition
From a point P on the bisector of angle AÔB, draw a line that forms four congruent angles with and intersects the sides of angle AOB, or their extensions, at points C and D. Prove that:
a. OC = OD;
b. for any point Q on OP, QC = QD
Does the O (in ROR⁻¹) mean something else here?
hi this isn't your channel
I’m sorry where I have to go?
i think you did R⁻¹○R
remember in R○R⁻¹, R⁻¹ gets applied first
here's this to help you lol
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Hello, I appologies as im French Canadian the terms I use might be different than what ive wrote as ive basically just tried to translate it.
I'm having a real hard time to understand and do "Formal System"
The first image are the rules that I have that allows me to transform things and so on
The second image is an example, but when Im trying to follow it I get blocked at the 2nd step.
So basically each line represents one step the result, and the rule used one what
(1) x v z premise
Means that is step one of my formal system, the result is x v z, and its just a premise available in my theorem
while
(2) ~x => v (1), r(9)
means its step two, the result is ~x => v after than I applied the rule 9 on the first result
When I look in the tables of rules above, I dont understand how the rule 9 is being applied and where the negation comes from
as x v z doesnt contain any negation
Rule 9 says:
A → B
Is exactly the same as
~A V B
Oh wait nvm they're combining two rules into rule 9
Rule 9 also says:
A → B
Is exactly the same as
~B → ~A
That "second rule 9" is what they're using in step 5.
I understand that, but what I dont understand is how my x v z can be applied in the rule nine, there is no negation in it
Okay we are talking about rule 2, not rule 5. My bad, I got mixed up
Then we refer back to the "first rule 9" lol
Rule 9 says:
A → B
Is exactly the same as
~A V B
Now, you're saying there's no negation. Note the negation needs not be there
It's the relationship between the symbols that actually matters
If I were to, say, substitute ~A in for A, then this is also rule 9:
~A → B
Is exactly the same as
A V B
so A v B can be applied the rule 9 ? you then switch it to ~A => B because you just "note" that there is supposed to have a negation at the start meaning that you have to inverse it at the end?
or yeah as you say you just subsitute it, but at the end you have to put it back?
(A => B) <-> (~B => ~A) <-> (~A v B)
is the same as
(~A => B) <-> (~B => A) <-> (A v B)
if I understand
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how is this expression valid
Is this photomath?
yes
They want to say sin^2(x) or (sin(x))^2
Yes it is that as well.
how do u get this from that
But cos(2x) = cos^2(x) - sin^2(x)
So from here.
Pretty much used both of them, but yeah.
2sin^2(x) = 1 - cos(2x)
sin^2(x) = 1/2 - 1/2cos(2x)
yea makes sense now
ty /!
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An infinite Geometric series that is going down is given. a1,a2,a3,,,an. its Quotient is Q. and its numbers are positive. using the numbers from the given sequence we set a new.
prove if the new sequence is a Geometric series or not.
<@&286206848099549185>
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find a set of parametric equations for the line of intersection of the planes 3x+2y-z=7 and x-4y+2z=0
Hello 🙂
Is that how I need to rewrite my equation?
I'm supposed to write a parametric equation for the line of intersection
I have the answer, I'm just not sure how they got there
x = 2
y = 1 + t
z = 1 + 2t
Right
then 3x+2y-z = 7
The question is how did he come up with the equation for the line
2y-z-1 = 0?
I don't understand how he came up with 0i+1j+2k
You can produce an equation that depends on y
or z whatever
what did he do
i dont see
Does it want intersection point
The first one can use the dot product definiton with cosine?
Ya I managed to get the angle easy enough
lets look at here
Then, we use that vector to take a cross product with the normals of both planes
Lemme see if I can snip my work into here
ok
hello is someone willing to help me with analytics geomtry ?
Did you finish the cross product calculation?
That is crucial in finding the normal to the intersection
When I did the cross products I ended up wiht 0i-7j-14k
hello
hi
@latent wolf You will handle it my friend
@young bane You can write to another channel, or dm
okay
@young bane But next time you want help, write to another empty channel
oh okay sorry
So then add that to the point you found by taking z=0, finding x and y from the two equations
Is it possible for me to share my screen in here?
No but we can have a miro https://miro.com/app/board/uXjVNOH9Mag=/
So you have a point. Now you need the normal
The normal is found by cross product of the normals of eq1 and eq2
So for the cross product of the normals of eq1 and eq2
I end up with 0i-7j-14k
<@&286206848099549185>
<@&286206848099549185>
Hello?
<@&286206848099549185>
@latent wolf Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185>
buddy relax
just tryna get some help fam
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My guy is in middle of the exam
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Does anyone know how to get the horizontal asymptote of this equation?
limit as x goes to infinity or negative infinity
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im not
oh wait
ok i closed my old one
Why do I multiply by conjugate
Does it matter if I multiply by 5-sqrt(7)
Wont that still cancel out
why is it +
,,<cancel>\def\CancelColor{\tc r}\f4{\cancel{5-\s7}} \c b{\cd \f{\cancel{5-\s7}}{5-\s7}} =\f4{5-\s7}
difference of squares
so you are not saying much by what you are doing
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14B please
how do i find the centre and radius of the circle of intersection
thats the equations
plsss
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9 = (10 - 1)
Mind you, that leads heavily into number theory
But binomial-esc
You'll see it every time now lol
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Is there any software I can use to double check my tuple relational calculus queries?
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@celest marsh Has your question been resolved?
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This is cc differential equations. He's explaining ERF.
I don't understand the first line. Shouldn't be (D+a)(D+b) ?
a and b are roots
on the second line, p' presumably means dp/dD or if you want ∂p/∂D
He's differentiating the first line. A step which I also don't understand
My first problem is the first line
So a and b are root of D^2-(a+b)D+ab
=
0
What you mean by root
It says root case
The roots of the characteristic polinomial.
Oh
if (d-b)(d-a) = 0, meaning they are roots then d-b=0 and therefore d=b, same concept for a
Yes this is what I thought, but why having a minutes there
I mean the second term coul also be positive right?
why would it be positive?
Ya not postive it could be anything
Why not?
Function of x and constant
I mean the second term of the diff
the minus sign isnt to tell you that the number is positive or negative
Not have function of y there
its to have you subtract instead of add if the root is plugged in
(x - 3)(x - 2) has roots 3 and 2 which can be seen by plugging them in
(x + 3)(x + 2) has roots -3 and -2 which can be seen by plugging them in
For second term try uv formula of differentiation
P(D) has roots when P(D)=0 therefore (d-b)(d-a) = 0, meaning that d-b is a root and d-a is a root therefore d=b and d=a are roots
I tried but o don't know what I have to differentiate
You have to differentiate p(D) with respect to D
Not respect to x
bruh
What I'm saying is
I could also have
(D+a)(D +b) right? This is just an example not a general rule
it no longer means anything if you do that but p(D) = (D + a)(D + b) sure is a polynomial that has the letters D, a, and b in it
its derivative dp/dD is (D + b) + (D + a)
Why means anything?
is that a bad thing?
well what even is the goal?
if it takes a single misread sentence to dislodge your understanding then you have some big questions to answer
what did you get before
I was following a video and he jumped on this proof.
I'll rewatch the video after work.
This doesn't help
it helps you no longer get lost by restarting back to "what was I stuck on again"
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could someone help me with this problem'
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hello
how can i solve this
2:3 is the ratio of foods delivered (fries to chips). if they had delivered 4 more fries, the rario would be 3:4, how mang fires n chips they delivered in total?
Assume there are 2y fries and 3y chips
Then the ratio would be 2:3
And then solve
how can i solve it is there a way to find out the total number other than substituting the choices
thank u for your response!
Wdym
Ok wait
Say there are f number of fries
And c number of chips
so f/c = 2/3 right?
yes
okok
okioki
ohh i see whre i got wrong
Look at the questin
(f+4)/c = 3/4
Yes
ohhh nice
You'll get 3c = 4(f+4)
3c = 4f + 16
Now you can substitute the value of c
And solve for f
But I think the neater answer would start with the fries and chips being 2y and 3y
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The sum for the real numbers a and b for which the limit (photo) is equal to:
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
start by calculting/simplifying the given limit
The limit of the square root would be +infinity I assume.
I never had this a and b unknowns to limits, I am quite new to limits, actually. Just about 2 weeks in.
true but what is the limit for ax
so you have infinity plus infinity right
we have to search for a value a thats gives us a finite limit
try to do that
try to get x^2 out of the sqrt
so get something like |x|sqrt(.....) - ax
Mhm..I will certainly try and think of a way, I will come once I'd find anything or give up.
yes try and lmk
You mean a forced factoring?
Of the x^2, such that we would have the x^2 out as x(something)?
yes so factor what is under the sqrt as x^2(......)
and then you can get the x^2 out of the sqrt
perfect
no so first
we have to simplify this
this can be done by getting rid of the sqrt
do you have an idea how?
Well, the limit of 1/x for either plus or minus infinity will always be 0?
yes
So, the radical will be 1
Ah, true.
x - ax = b?
no you made a mistake
ax will not change
it is |x| that has to be rewritten for negative x
because of the absolute value
so the term ax will remain untouched
Hm, because we don't touch ax at all and let it remain positive?
I thought by x being negative, it would be a no brainer to write "-ax"
The absolute value makes sense, obviously.
so want to rewrite the absolute value in terms of x and not |x| so we can a common factor with ax
how to do that in case that x is negative
x(1-a)=b?
not really\
-x(1+a)=b ?
Into negative, by multiplying with (-1)?
yes so we find that...
|x| = -x when x<0
which is true in our case because the limit is negative
so what do we get now?
ax - x = b?
yes
we can rewrite as
(a-1)x=b
now think of a case where this limit can be true
Ohh because of the specific x requirements.
Great, now...
this step
in what case is this limit never infinity
When a-1 and b are 0?
Which a+b is just 1
Bingo. We did it.
Thanks for the help man, appreciate it lots.
Have a great day/evening!
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If you already know how to calculate the maximum likelihood from earlier parts, what part of this alternate version is challenging
I'm not going to read that, but if you can calculate this you should recognize that the computation for an MLE is broken up into a few steps. Namely writing down the likelihood function, then optimizing it.
The optimization step is just calculus, you find a critical point and you exploit the log convexity of the normal to guarantee that the critical point is the optimal value
Now, you have a case where mu must lie in [0,1]
So either the critical point is in [0,1] or it isn't. And you should know from Calculus where the optima lies if there is no critical point in your region of interest
The point is that by drawing a picture of a quadratic on the interval [0,1]
You have your answer
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@wicked willow Has your question been resolved?
can you reformulate the question neatly from the beginning ?
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Find the number of ways to distribute 21 identical oranges among 3 children such that all of them get atleast 2
i know i can use ramanujans partions
and i can use multinomial
apart from these two, is there any other way to solve these questions?
@sturdy rose Has your question been resolved?
i dont know the answer
but using partions, it does come out to be 136
im pretty sure i used partitions
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If you draw 3 cards from a standard deck of 52 what is the probability your first card is a space given the second and third card are a spade?
do you know what revised probability is?
No
I have setup $E_i$ to be the event that the $i$-th card was a space: $$P(E_1|E_2E_3)$$
o.O
hm
Im doing it like this
I expand $$P(E_1|E_2E_3) = \frac{P\left(E_{1}E_{2}E_{3}\right)}{P\left(E_{2}E_{3}\right)}$$
o.O
Using basic properties of conditional probability
but I don't understand why my answer is wrong
$$\frac{\frac{4}{52}\cdot\frac{3}{51}\cdot\frac{2}{50}}{\frac{4}{52}\cdot\frac{3}{51}\cdot\frac{2}{50}+\frac{48}{52}\cdot\frac{4}{51}\cdot\frac{3}{50}}$$
o.O
For P(E1 E2 E3) I thought we have 4 in 52 cards being a space, 3 in 51 on the second draw, and 2 in 50 on the third draw
then for P(E2 E3) that is the situation P(E1 complement E2 E3) + P(E1 E2 E3)
the cards arent replaced right?
well what youre doing is what i would do, so the name isnt important
these are the identities we are given
I used the top one
oh I computed it wrong because I didnt know what a deck of cards was I thought spade was a card denomination like king or queen
$$\frac{\frac{13}{52}\cdot\frac{12}{51}\cdot\frac{11}{50}}{\frac{13}{52}\cdot\frac{12}{51}\cdot\frac{11}{50}+\frac{39}{52}\cdot\frac{13}{51}\cdot\frac{12}{50}}\ $$
o.O
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,rotate
Question 85
I choosed one seat for the child that come first
6c1
And
Then
For worst case
Another child have to choose another seat
So 5c1
+1 for the the possibility that the second child get the seat he needed
And other three got their respective seats
Divided by total cases
I am not able to find total cases
And idk if what I did is correct or not
Did i choosed the cases correct
hold up
K
ooh aakash byju's
Lol
jee? 😭
yea doing that
cool
well from what I could deduce, we know that the first student must select a seat out of any of the 3 seats that are not of the last 3 people. so the probability he does that hs 1/2 (3/6). the next student must also select a seat randomly that isn't of the last 3 people, so 2/5, and then 1/4. I'm giving it a second thought though because im not really sure if that would be the answer because I think im missing something
so like (3/6 * 2/5 * 1/4)*120 🤷♂️
alright
Can you please check 84 also I got the answer 6
yeah that's right
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✅
Wait I have one more question
shoot
Yup
Any progress??
well all I could think of is using brute force and expanding it
but im sure there's some other way out
It would take years
Idk
bro
i got it
what u can do is
u can create a polynomial equation
1/(a+x) + 1/(b+x) + 1/(c+x) + 1/(d+x) = 2/x
now roots of this are w, w^2
make it a 4 degree equation
and use sum of roots
product of roots
the answer is 2
or you could divide both sides in the first equation by omega, then compare the denominators or something (aw^2 + 1 = a + w^2) and I I'd like to think that'd get you somewhere
u got the answer?
yeah
kk
this would make it easier
yeah
because that gives you a = b = c = d = 1
so its 1/2 * 4 = 2
oh im dumb
nvm
the thing is
here this method is allowed
cuz there is symmetry
yeah
its not the best method in other cases but in other cases im sure there's some other way
yeahhh
Thanks guys
ok
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k
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What is derivatives of functions?
?
"functions"?
a derivative is the differentiation of a function wrt to x (mostly)
wrt?
with respect to
ahh okay
also
since the average rate of change is written as Δy/Δx, why is instantaneous rate of change written as dy/dx?
is it just to make them visually different?
some people even interchange the two
but theres a big difference
like literally
one of them indicates a very minute change
and one indicates a considerably big chance
so which is which?
okay thank you^^
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Trying to better understand the proof behind this proposition in my lecture notes.
I think the idea behind the whole proof is that if you can find a bounded subsequence, then by Bolzano-Weirestrass theorem, there exists a convergent subsequence of the original bounded subsequence. If there isn't a bounded subsequence , meaning no convergent subsequence, then by the definition of a limitpoint, then the limitpoint set is empty. i've probably worded it really poorly but I hope it makes sense. pictures include the proposition with its proof and then the definition of a limitpoint set
I just want some clarification is my reasoning is correct or not in order to better my understanding
ah the definition didnt send. here it is:
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Is anyone here familiar with Radix Conversion in Hash values?
Here's one of the given:
Key Value: 24680
Radix Conversion (Base 9 to Base 10): 56
But when I converted 24680 from base 9 to base 10, I got 16596 so the Radix Conversion value should have been 96.
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Idk how to start... Do I rationalize the denominator? Do I open tan into sin and cos?
i'd recommend starting with a sub like u=sqrt(x)
same
then it will become easier to work your head around it.
try $u=\sqrt(x)$ as others here suggested
Why am. I here
I don't know what sub is...
And sqrt(x) = u
Yes, but you need to rewrite it in terms of u as well
Yes
Perfect!
So now I should claim integral and open (u) and my question is solved?
It's correct,Awesome! Thanks!
Now I know how to use "u substitution"
Can this also be used in limits?
Or it's for integrals only
Do you mean improper integrals?
Limits and integrals HAVE A CONNECTION?!?!
Well just regular limits, but I guess not.
What.,...
How and where do I even begin?
The sin(4x) is bothering me a bit. Can you use a trig identity to rewrite it?
Maybe in terms of something depending on 2x
Nah, in regular limits there is no chain rule.
For the cos²(3x) yes but for the sin i don't think so
Can I claim a 2 in any way from the sin's degree (4x)? To make it a 2x or that's mathatically impossible
My phone battery is dying, I'll be back after a few minutes
You can use double angle identity for sin(4x)
Making it (2sin(2x)cos(2x))?
Exactly
The reason why you want to do this is to substitute.
Because now you only have sin(2x) and cos(2x). That is advantageous for a substitution
I wonder can i also pull out a (minus) from the denominator and separate the minus with the (1) to make it (1-cos^2(2x)) to tun it into -sin^2(2x)? Or I am now making things up?
do u need the steps?
I think I have to claim the sub for cos(2x)?
1+cos2(2x) actually
if u take it, differentiate it with respect to x, you'll get the numerator which is 2sin(2x)cos(2x) with an extra -2
u already made the numerator like this
so its easy from there
Got it, thanks!
no problem 😄
Also this was correct?
yep
I had doubts about it
ignore the messy numbers its a bit rushed my bad
nah you were on the right track
Please do not give out full solutions. The point of a help channel is to guide the helpees and not do the exercises for them.
Just a question off that problem, I can also do the same for let’s say sin(3x), right? As long as I can pull 2 out of its “degree” that identity can be used?
oh shit alright ill delete it
how would u do the same for sin(3x)?
Well it helped me understand but yeah, thanks for confirming my answer xd
Don't worry 🙂 It's nice that you are taking your time to help others!
Ohhh you can’t? Oooh i thought It’s done by like this (3x -> 2(x))
as long as you get an even number, but i doubt sin(3x) can be made into an identity because those are double angled identities, you would need an even angle for sin to pull of that
its alright we all go through that lmao
Also sorry for not using mathematical terms I didn’t learn it in English to recognize them
nah even i dont know enough and appropriate mathematical terms, im literally gambling with the words im using here
Lol
From which country are you if I may ask?
Ok that’s all for now, I will go back to study and might…well…will come back later because I’m sure I will have more questions
Thank you all again!
So the channel can be closed?
im from india gang 💯
i should do that too
and what country might you be from
Germany
You are The true hero 🙏
hopefully
thank you little soldier
im assuming you're from india too
Neighbors xd
Have you already decided for a university here?
not yet, but the uni i plan to go this year advances in letting their students go abroad to take their studies further so uh yeah
all depends on that one uni
besides i would need to learn german
Would be funny if I was tutoring one of your exercises
But ofc unlikely
would be really funny
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oh uh
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Question:
Jessica stretches her arms out 0.60 m from the center of her body while holding a 2.0 kg mass in each hand. She then spins around on an ice rink at 1.1 m/s.
What is the combined angular momentum of the masses?
If she pulls her arms in to 0.15 m, what is her new linear speed?
My work so far:
r = 0.6 m
m = 2 kg
v = 1.1 m/s
The combined angular momentum of the masses is given as
L = mvr + mvr
L = 2mvr
Inserting the values:
L = 2(2)(1.1)(0.6)
L = 2.64 kg m^2/s
I'm stuck on how to calculate the new linear speed. If anybody could help out, it would be appreciated.
bro mathematics server for a reason
i ssuck at phy
He means that this is a physics problem in a maths server
altho i shall try
oh my bad
actually it doesnt matter
No worries, well you are lucky someone already tries this
really?
MagnusOP said he'd try?
nvm i thought somebody had already asked this question
but u need phone verificaation and shit to chat in that server
Ohhh
so idt anyone shud mind phy questions in this server
uhm
She then spins around on an ice rink at 1.1 m/s.
how do you spin with a velocity?
or do they mean this as the velocity of the balls
masses
kk
ok so
quick tip: dont calculate stuff
in this case, you correctly got the value for L
you also got a formula
L=2mvr
if she pulls her arms in, angular momentum will be conserved
same question
if we call that new momentum L', then we get:
L=L'
the new angular momentum will have the same formula:
L'=2m' v' r'
note however, that m didnt change, so m'=m
so now we can set L equal to L' and rearrange to v'
we dont wanna look at values right now
putting in values before the end just makes it messy
we have L=2mvr, L'=2mv'r'
with L=L', we get
2mvr=2mv'r' => vr=v'r'
that way we also avoid rounding errors
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Ciara is swinging a 0.015 kg ball tied to a string around her head in a flat, horizontal circle. The radius of the circle is 0.70 m. It takes the ball 0.60 seconds to complete one full circle. Calculate the tension in the string and its direction that provides the centripetal force acting on the ball to keep it in the circular path. (3 points)
0.0077 N, toward the center of the circle
1.2 N, toward the center of the circle
0.0077 N, along the line tangent to the circle
1.2 N, along the line tangent to the circle
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astro said:
Ciara is swinging a 0.015 kg ball tied to a string around her head in a flat, horizontal circle. The radius of the circle is 0.70 m. It takes the ball 0.60 seconds to complete one full circle. Calculate the tension in the string and its direction that provides the centripetal force acting on the ball to keep it in the circular path. (3 points)
0.0077 N, toward the center of the circle
1.2 N, toward the center of the circle
0.0077 N, along the line tangent to the circle
1.2 N, along the line tangent to the circle
ok so
i get something completely different than the 4 choices
but the direction should be easy
do you see what it should be?
@ocean basalt
i think so
centripetal forces are perpendicular to the movement
so in this case they point towards the center of the circle
but is the force 1.2 N or 0.0077 N?
given m, r, T
we can first derive the angular velocity w=2 pi / T
and then we can use the formula for the centripetal force
F=m v^2/r = m w^2 r
the thing is that when i do the math here, i dont get 1.2 or 0.0077
oh well, they might have rounded
yeah thats probably it
did you try to calculate it @ocean basalt ?
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Need to find the perimeter of the triangle ABC , the ratio of the sides are not common ratios and the ar. Of the inner triangle is 60cm²
So like the ration that some dot split AB is 1 : 3?
Yeah thats good
Anything u can think of doing next?
Fun problem i will think about it
Yeah thanks I have been thinking about it for 2 days
Any progress?
Nothing
Came up with something but my teacher proved it wrong
I hardly believe this can be solve analytically
Can u show me how?
But i mean everything can be solved analytically so...
Like let point R be origin