#ug-maths-physics

1 messages · Page 3 of 1

rancid schooner
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How’s the campus food?

vestal swift
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kant's principle of humanity :)

stuck rapids
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give us some advice

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cmon

vestal swift
rancid schooner
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Show campus food pics

vestal swift
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more worried abt my grades

vestal swift
rancid schooner
stuck rapids
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HAHAHAHHA

vestal swift
rancid schooner
stuck rapids
rancid schooner
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Singapore has good chicken rice.

stuck rapids
#

? food as an advice

rancid schooner
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Enjoy your food :)

stuck rapids
vestal swift
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damn bot has good taste haha nice burger

rancid schooner
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With an unusual name

vestal swift
stuck rapids
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he is indeed rich

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HAHAHAHAH

vestal swift
stuck rapids
#

yi pou gai

rancid schooner
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That’s my only square meal for the week

stuck rapids
rancid schooner
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Channels here getting very quiet

stuck rapids
#

wht about the aussie breakfast

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rm 42

rancid schooner
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That was a few weeks ago

vestal swift
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fuiyoh wtf

rancid schooner
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Or a few months ago

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inflation

vestal swift
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why is it n and k

stuck rapids
vestal swift
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k is fixed or ?

vestal swift
stuck rapids
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else why would u spend 40 over ringgit for a meal

vestal swift
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i come here eat grass

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jk

stuck rapids
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maybe u ordered a drink also

rancid schooner
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k is already a factor of n!

rancid schooner
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So k|n!
And k|k
So k|(n!+k)

vestal swift
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i digest sia

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wait so base case is 2! + k is divisible by k ?

rancid schooner
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It’s given that k is less than or equal to n

vestal swift
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wait so for 3!+k then it must be divided by 2, 3?

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then 4!+k , must be divided by k=2,3,4?

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shitz

rancid schooner
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yes

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well not at the same time

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but for any given k

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choose any k, and it works for that k

little widget
vestal swift
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or use strong MI

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i still dk how strong MI works

rich wraith
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found this in another server

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find A

little widget
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Very sussy diagonal matrix

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Also very sussy pattern

rancid schooner
tawdry gull
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there is double math induction

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...which i have no idea how to do, i just know it exists

rancid schooner
#

Inception is a 2010 science fiction action film written and directed by Christopher Nolan, who also produced the film with Emma Thomas, his wife. The film stars Leonardo DiCaprio as a professional thief who steals information by infiltrating the subconscious of his targets. He is offered a chance to have his criminal history erased as payment fo...

long aurora
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stupid q but might find the answer from a physics student, i was wondering, are air particles affected by acceleration of free fall? do they experience g (9.81) ?

long aurora
rancid schooner
stark wave
verbal nova
little widget
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Assume acceleration constant

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Assume zero friction

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Assume all strings are inextensible

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Assume u can fuck with the coordinate system while the linear algebra teachers have a seizure

rancid schooner
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He’s a very good director.

long aurora
long aurora
rancid schooner
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If all air particles drop to the ground then people would suffocate standing up.

stuck rapids
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Wtf HAHAHAHAY

rancid schooner
serene scarabBOT
rancid schooner
rich wraith
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no idea

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no one replied to it on the other server either🥲

rancid schooner
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If it’s A^20 + B^21 then it is possible to get a “nice” answer for A and B.

verbal nova
rancid schooner
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Otherwise perhaps not.

rancid schooner
rich wraith
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"People suggested that the matrix is top triangular so there is a pattern when multiplying by itself"

rancid schooner
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Yes it clearly is top right triangular but what is the final answer?

rich wraith
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I don't think anyone knows

brazen rampart
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halp plz im cri

rancid schooner
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Nice question

rancid schooner
vestal swift
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@rancid schooner :')

rancid schooner
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Sentence on the left doesn’t seem to make sense. 🤔 @tawdry gull ?

vestal swift
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For the circle one it's a subspace right?

rancid schooner
tawdry gull
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When proving subspace, u need to prove the 3 conditions are met right. He/she is asking to prove that it is NOT a subspace, then we have to show it doesnt satisfy at least one of the conditions

little widget
# brazen rampart

@rancid schooner im quite confused if we can use the fact that detA = detA^T and det(AB) = det(A)(B) how does it equal zero??

rancid schooner
little widget
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Yeah if it isnt seems trivial

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Oh lord im fucking dumb

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Thats the place to fill it in i see

rancid schooner
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😊

little widget
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Thanks for the observation

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I dont have the keenest eye

rancid schooner
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It’s not very intuitive. They should just leave it blank.

little widget
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No they prolly did

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Op did not 😭

rancid schooner
tawdry gull
rancid schooner
rancid schooner
little widget
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Ehhh

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Thats lame

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Everything was lined up so beautifully too

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The 20 and the 21

rich wraith
rich wraith
little widget
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The diagonal matrices

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Wth man

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Troll q

rancid schooner
tawdry gull
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oh and also, could u please check my hw6 q2b

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my friend (an IMO guy) and i didnt find a way to solve it yet

rancid schooner
tawdry gull
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wow

rancid schooner
tawdry gull
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yes thank you 🙏

rancid schooner
tawdry gull
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interesting

rancid schooner
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Anyway I found that the value of the leading diagonal elements is very close to: 2^ln(20/21). But not exactly so.

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It should be c where c^20 + c^21 = 1.

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The two edge elements are in the ratio 20:21.

rancid schooner
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Yes. Using the solver on Excel.

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Excel can handle simple matrix operations.

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Anyway if you modify the problem to
A^20 + B^21 = (given matrix on RHS)
then it’s easier to solve analytically.

rancid schooner
main topaz
rancid schooner
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You could write some Python code but it would take too much effort.

main topaz
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Pretty out of sync with math atm, college apps destroying the few brain cells I have left

rancid schooner
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Anyway I just wanted to see that a solution exists.

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Good luck. Where are you applying?

main topaz
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Working on ED for US atm

main topaz
main topaz
idle rainBOT
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Gave +1 rep to AlexV#1811

rich wraith
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"IF P, then Q" is true when P is false and Q is true

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I don't get how :/

rancid schooner
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So it must be false

vestal swift
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Something like "if elephants can fly, then I am Superman" hahahha

rancid schooner
tawdry gull
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f(x) is bounded

rancid schooner
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no, it's stated that f(x) → +∞ as x → ∞

tawdry gull
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eh, it didnt

rancid schooner
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which is true for f(x) = lnx

tawdry gull
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its the sequence that goes to +infty

rancid schooner
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can we make up a sequence that follows ln(x)? i.e. xₙ = n and f(x) = ln x?

tawdry gull
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yeah sure

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but f(x) can be anything

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as long as it is cont and bounded

rancid schooner
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ok bounded. first line.

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so some sort of asymptotic function then

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maybe a logistic function

tawdry gull
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it could also not converge

stuck rapids
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Why do proofs even exist

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😂

little widget
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if anyone can solve this itd be sick

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i keep seeming to get 15.696N

vestal swift
vestal swift
little widget
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wow i like option D

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no no dont put in A choose D

rancid schooner
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Logic

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Prove that you exist

little widget
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alex u fancy some physics this morning/afternoon

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veri trivial perhaps

rancid schooner
vestal swift
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Nope

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The answer is C

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:')

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D makes more sense to me too

little widget
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well obviously

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its a mcq

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why would both be correct

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in before bamboozle tho

vestal swift
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Wuh

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????

little widget
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you can pick A

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or D

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but D is A

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theyre the same answer

little widget
vestal swift
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But d got contradiction no?

stuck rapids
rancid schooner
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The politicians won’t be very happy with B

little widget
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I feel like this q is gaslighting me rn

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Its like A is applying itself to D

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AHHH

vestal swift
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LITERALLY I DONT GET WHY ITS C

rancid schooner
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It’s a logic prank by the lecturer

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A circular reference.

little widget
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I hate ur lecturer

stuck rapids
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Both a and c are correct

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Hahahahaha

rancid schooner
rancid schooner
# tawdry gull but f(x) can be anything

since xₙ → ∞ as n → ∞,
(xₙ + B)/xₙ = 1 + B/xₙ → 1 as n → ∞, i.e.
(xₙ + B) → xₙ as n → ∞.
So, as n → ∞,
f((xₙ + B) → f(xₙ), i.e. f((xₙ + B) - f(xₙ) → 0.

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Is this valid?

tawdry gull
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that is given f(x) converges right?

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or r u assuming f can be either converge diverge?

rancid schooner
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no assumption

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except that f(x) is continuous

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and bounded, as given in the question

tawdry gull
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i see

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hmm

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wheres the use of boundedness there?

little widget
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I was looking at the force being applied to block B not A

tawdry gull
rancid schooner
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Then, xₙ + B = B(1 + ln n) → B ln n (= xₙ) as n → ∞.

tawdry gull
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hmm i dont think so

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suppose f(x) = sin(x^2) and B=10

rancid schooner
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Well it would work in the case where f(x) has period B.

tawdry gull
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f(x) may not have a period

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so thats the problem 😭

rancid schooner
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Just pointing out the one instance where it would work :)

tawdry gull
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yeah haha

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if it was periodic then it would surely work

tawdry gull
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@rancid schooner

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i got the answer

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do u want to take a look?

rancid schooner
tawdry gull
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okay sure haha

rancid schooner
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Let me take a look again when I have some time :)

tawdry gull
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do u want a hint at least?

rancid schooner
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Haha ok

tawdry gull
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use MCT and IVT

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did i say that already?

rancid schooner
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Ok similar to what was suggested in the question

tawdry gull
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ah okay haha

rancid schooner
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I think you’re supposed to prove that a sequence exists,not necessarily find a particular sequence, is that right?

vestal swift
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Fellow math gods

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How to develop math intuition to solve math problems :')

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N the proofs

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Coz

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I suck :')

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And I wanna die coz I'm not cut out to study mathtruejoy truejoy

tawdry gull
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which would help

stuck rapids
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why do proofs even exist

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what on earth

rancid schooner
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Otherwise how would you know that 1+1 = 2?

vestal swift
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Where ah besides trusty old 3b1b :')

vestal swift
rancid schooner
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Must start from axioms

verbal nova
#

Guys

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I have a discrete math mid term tonight

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And I cant stop wondering how this subject is actually useful

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Plz someone tell me any famous use of discrete math

rancid schooner
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Discrete maths is fun

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Without it we wouldn’t be able to count anything

verbal nova
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😭

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I cannot detect the fun at all man

tawdry gull
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especially cs deals with discrete things

main topaz
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uhh considering this chat is quite active could someone please help with this MAT question?

rancid schooner
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(e)

rancid schooner
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|| then solution is x=2n𝜋+y, 2n𝜋-y for integer n ||

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nice question

main topaz
idle rainBOT
#

Gave +1 rep to AlexV#1811

rancid schooner
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😊

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The other element of the solution (not required in the question) is ||sin x + sin y = 1||. Visible when you plot the graph.

rancid schooner
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Like the CROCODILE question 😄

verbal nova
rancid schooner
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What discrete maths topics are you doing?

verbal nova
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very first chapter, propositions, inferences, predicates, quantifiers, intro to proofs

rancid schooner
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That sounds rather dry

vestal swift
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I failed my discrete math midterms :')

verbal nova
#

stop scaring me bro

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if you wanna pass then you study

vestal swift
#

Dw you'll pass

verbal nova
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studying is necessary for passing

vestal swift
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Necessary but not sufficient

vestal swift
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And you'll do fine

verbal nova
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either you study or dont pass

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you cant pass and not study

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let the argument be that if you wanna pass then you study and you didnt study therefore you didnt pass

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Modus tollens moment

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true for all students

vestal swift
#

Tf

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Feels like contradiction

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But idk

rancid schooner
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Hold a study session

main topaz
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uhh second part??

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do they mean like ||the point (a,b) say lies in S such that it itself is its nearest point?||

verbal nova
rancid schooner
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Perhaps S is the subset of points on a circle with centre (a,b).

tawdry gull
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as alex mentioned, a boundary of a circle with centre (a,b) would work

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since there are infinitely many points equidistant to (a,b)

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so there is technically no "nearest point"

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or an empty set would work too, an empty set by definition is a subset of any set

main topaz
tawdry gull
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oh yep

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thats for iii)

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or an ellipse centred in (a,b) would too

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for ii), any open set would work actually

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as long as it doesnt contain (a,b)

rancid schooner
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Where is this from?

main topaz
#

uhh sorry but I still dont get (ii)

tawdry gull
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the open set?

main topaz
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x^2+y^2>1 would be considered an open set right?

tawdry gull
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yes

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just make sure it doesnt contain (a,b)

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so u can make (a,b) the centre

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(x-a)^2 + (y-b)^2 > 1

main topaz
#

AHHHH i got it know, they meant there's no one point that is nearest right?

tawdry gull
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no points at all

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not even 1 or 2 or more

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completely none

main topaz
#

wait no

rancid schooner
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So that’s the empty set

main topaz
#

closest*

tawdry gull
#

except it has no boundary

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because it is an open set

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:)

main topaz
#

oh fudgee

main topaz
idle rainBOT
#

Gave +1 rep to The_Pierrot#7889

tawdry gull
#

gotcha

rancid schooner
#

So for any point that is close you can find a closer one

main topaz
#

sheesh mat is hard

tawdry gull
#

exactly

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hence no nearest point

rancid schooner
#

Like an infinity pool

main topaz
idle rainBOT
#

Gave +1 rep to AlexV#1811

rancid schooner
#

😊

main topaz
#

i dont think i'll be able to prepare for mat in 10ish days

tawdry gull
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do ur best

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try watching vids for it too

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znotes got a playlist on that too btw

main topaz
main topaz
rancid schooner
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Watch Oxford Mathematics Plus videos on YouTube by James Munro.

tawdry gull
#

oh i see

rancid schooner
#

A nice MAT question was this: what is the maximum value of (ax+by) where a, b are positive and x² + y² <= 1?

main topaz
rancid schooner
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No

verbal nova
#

statistics and probability are so sexy

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its so hot how everything connects

verbal nova
#

Guys how does Universal Generalization work 😭

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how does the argument P(c) conclude that ∀xP(x)

stuck rapids
#

😂😆

verbal nova
#

Finished the midterm

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Went good

vestal swift
rancid schooner
#

Which university/country/course?

verbal nova
rancid schooner
vestal swift
#

Uni mathematical induction next level compared to furthermaths 😭😭😭

tawdry gull
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technically induction can be done as long as it proves along the integers so... :D

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there is also math induction on a chessboard

rancid schooner
#

classic example of recursion

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and also classic example in a course on theory of algorithms

main topaz
vestal swift
#

Can anyone help me out with this? Proving it is a subspace, I have a LA quiz tmr😭😔

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Idk how to prove that this satisfies closure under scalar multiplication

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.
This was my approach:
S={(a-c,b-c,0); a-c∈R, b-c∈R}
We can rewrite it as
S={(x,y,0); x,y∈R}, where
x=a-c
y=b-c
this is a x-y plane in R³ which contains the origin

vestal swift
tawdry gull
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for any real number t

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u will get ta(1,0,0)+tb(0,1,0)+tc(-1,-1,0)

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if t>=0 then it immediately follows that tv is in S

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if t<0

vestal swift
tawdry gull
#

let u=-t so that u>0
ta(1,0,0)+tb(0,1,0)+tc(-1,-1,0)
= ua(-1,0,0)+ub(0,-1,0)+uc(1,1,0)
= uc(1,0,0)+uc(0,1,0)+(-ua,-ub,0)
= (uc+ub)(1,0,0) + (uc+ua)(0,1,0) + (-ua-ub,-ub-ua,0)
= (uc+ub)(1,0,0) + (uc+ua)(0,1,0) + (ua+ub)(-1,-1,0)

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all ua, ub, uc are nonnegative

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so its in S

vestal swift
#

Uh wait why not (uc+ua)(1,0,0) ah

tawdry gull
#

because top of third vector have -ub

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so have to +ua to have -ub-ua

vestal swift
#

Hold on lemme digest digest 🥺

tawdry gull
#

oke

vestal swift
#

Oh

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Omg

idle rainBOT
#

Gave +1 rep to The_Pierrot#7889

tawdry gull
#

okeh 👍

verbal nova
#

what language

vestal swift
vestal swift
#

Linear alg

verbal nova
#

Why cant math just be calculus

tawdry gull
#

cuz calculus is not enough 😭

vestal swift
#

Don't worry you didn't pick maths like me :')

verbal nova
#

whatever bro

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❤️ ❤️ ❤️ ❤️ ❤️ ❤️ ❤️

tawdry gull
#

miller miller

rancid schooner
#

What is that object to the right of the whiteboard?

vestal swift
#

Did I choose the wrong course :")

rancid schooner
#

Don’t believe everything you read

rancid schooner
stuck rapids
rancid schooner
#

Ask @tawdry gull 😄

stuck rapids
#

why not u

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HAHAHAH

vestal swift
#

I'm like dying in LA

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I can't write proofs

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Which is the essence of math 😞

rancid schooner
#

Just copy from sample solutions as an exercise and you’ll get the hang of it

stuck rapids
#

i struggle with proofs as well

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😦

vestal swift
#

I copy alr still shit

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😔

rancid schooner
#

You’ll get better :)

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Host a study session!

vestal swift
vestal swift
#

@rancid schooner @tawdry gull :')

rancid schooner
#

Probably EᵀM or something like that

tawdry gull
vestal swift
tawdry gull
#

other marks come from explanation :)

vestal swift
#

I got 0.5/4 :)

tawdry gull
#

ME is basically the rows of M multiplied to columns of E

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which basically means column i of M becomes Ci+c Cj

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because in E, column j has a c in it

little widget
#

People jus say “just do the proof bro try not to look at solutions”

rancid schooner
vestal swift
#

That you can't find any pattern in it

little widget
#

Well ur not trying to find a pattern

vestal swift
little widget
#

More like developing a thought process

vestal swift
rancid schooner
#

What do they teach during tutorials?

little widget
#

Eh itll take time

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Im shit at it too

rancid schooner
#

Isn’t that what it’s for?

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Some universities have a maths cafe.

little widget
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Yea i hope in ur proofs class its not just

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The types of proofs

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End of course

little widget
rancid schooner
tawdry gull
#

we have an elite math class

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which... is not easy to get in

rancid schooner
#

Is that in the first year?

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Do they give free coffee?

little widget
#

Man they call it “elite”

vestal swift
#

I rlly think I'm not cut out for maf :')

tawdry gull
rancid schooner
#

Now I feel like having wine and cheese 🍷 🧀

rancid schooner
tawdry gull
#

nope

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only chern class students get to do it

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which im not

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or maybe not yet

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who knows

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i dont have high expectations

rancid schooner
#

Not yet.

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Anyway you can still buy wine and cheese for yourself.

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Maybe we can have a ZNotes wine and cheese study session 😄

vestal swift
#

doobee's dumb qs

jagged quarry
#

help needed

verbal nova
jagged quarry
#

Needs to be solved by some ratio method

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The topic is ratios, percents and proportions

verbal nova
jagged quarry
#

-_-

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BS

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This from 101 buisness maths

tawdry gull
#

@rancid schooner differentiation

rancid schooner
tawdry gull
#

wouldnt be fun if differentiation is just the way it was

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hahaha

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try doing 1b

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its nice haha

rancid schooner
#

cos² (πx/2)?

tawdry gull
#

no....

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it must be decreasing haha

rancid schooner
rancid schooner
#

For the last part

rancid schooner
# tawdry gull

The optional part on Hermitian Polynomials looks interesting

tawdry gull
tawdry gull
rancid schooner
rancid schooner
tawdry gull
#

do have fun with the questions haha

rancid schooner
stuck rapids
#

elloooo..how to approach this question after finding the solution space of S xD

tawdry gull
#

is it just M={v1,v4}? cuz pivot is in column 1 and 4

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so rank(S)=2

blazing wraith
#

can someone help me plsss

idle rainBOT
#

Help needed <@&597104882482413589>

verbal nova
#

wait, one sec

unique zodiac
#

I thought it was asking for the max. and min. values the graph can yield

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If you're looking for the point where dy/dx=0 its quite simple: x = -2.4

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But theres ofc more to it than that bcuz its 10 marks TT

verbal nova
#

No wait

unique zodiac
#

thats quite dark aha

verbal nova
unique zodiac
#

mmm icic

verbal nova
unique zodiac
#

:(

verbal nova
#

the abs maxima could be -1 or -5 too

unique zodiac
#

yeah

#

Well in that case, u have one local max, we can check if its a min/max later.

In the range x = [-5,1], the graph is always negative (because for terms to the power 2/3, you're squaring it and then taking the cube root so its a positive number. Then you multiply by x which is negative)

If you have a term s.t. f(x) = 0, that will be the absolute maximum.

From the dy/dx equation, theres a certain point where we cant evaluate dy/dx, try using that value in f(x) and see what u get

#

bruh u spoiled it for him

verbal nova
#

Ah shit, lemme hide it

#

||Looks like absolute Max is where y = 0 which looks to be -4
and absolute Min is f(-5)||

#

@blazing wraith

stuck rapids
unique zodiac
#

For the absolute minimum, we can check that when dy/dx=0 is a turning point, it is the local minimum. To find if its the abs minimum, compute x=-2.4

Then, using the graph of the derivative, you will find that the point where dy/dx = 0 is local for a certain domain, now check if thats true for the remaining domain (by subsituting the most extreme value of that domain ie. endpoints, and then compare)

#

If ur not going to use a calculator, its helpful to write dy/dx which ive computed earlier as: 1/(x+4)^1/3 * (5x+12)

blazing wraith
#

@verbal nova @unique zodiac thank you so much! ill have a look and if thers any questions ill ask you guys again :D

idle rainBOT
#

Gave +1 rep to Brave#5303, ukan#9821

blazing wraith
#

i cant understand the way to derivative, i thought outside bracket then only inside

unique zodiac
#

Oh, here I'm using the product rule, so bcuz u have (3x)*(x+4)^1/3 , u have to use the product rule

blazing wraith
#

haha kinda LMAO

unique zodiac
#

💀

#

moment

#

For the first part im sure uk how to get, for the second part its: 3x * 1/3 * (x+4) * (1/3 - 1) * (d/dx x+4)

verbal nova
#

@blazing wraith hows data science 😎

blazing wraith
#

awesome for now but some places kinda drowning cuz bad lecturer

#

me trying to study by myself haha

verbal nova
#

every subject is killing me

blazing wraith
#

yea im bad at calculus

verbal nova
blazing wraith
#

calculus 1

verbal nova
#

I see I see

#

for some reason we starting with multivariable calculus

blazing wraith
#

whats that??

#

i will study calculus 2 in other semester

#

forgot which one

verbal nova
blazing wraith
#

damn :o

#

so is this correct?? or is there anything missed out

#

@verbal nova @unique zodiac

verbal nova
# blazing wraith

actually from the graph I sent, the abs max appears to be f(-4) = 0

unique zodiac
#

u got the min. value correct which is cool

#

but yeah the abs max is (-4,0)

#

ur right in assuming that if the turning point isnt the local max/min, then one of the endpoints would be

#

Here we only have one turning point which is a local minimum, then one of the endpoints would be the abs. minimum (if the turning point isnt). It doesnt tell us anything ab the abs maximum.

blazing wraith
unique zodiac
#

Yea lme guide u there

#

Heres sm food for thought

#

If u show that f(-2.4) is a minimum, isnt it weird that f(-5) is somehow lower?

#

Bcuz u didnt find any other turning points, so its quite strange that f(-5) is lower than f(-2.4) isnt it

#

Now think: How is that possible, between -2.4 and -5, how did the derivative suddenly flip signs? Where could it have happened? (Hint: Look at the expression for dy/dx)

verbal nova
#

just make a graph

unique zodiac
#

chii in the exam

blazing wraith
#

HAHHAHAHAHAA

unique zodiac
#

Unless u cn use a graphing calc in the exam, u have to get it analytically somehow

unique zodiac
#

dy/dx = 1/(x+4)^1/3 * (5x+12)

here its not possible to get a derivative at the point x+4 = 0, x = -4

#

But the point on the graph does exist, so u have to see what happens there

verbal nova
#

You guys took F Math?

blazing wraith
#

no :(

verbal nova
#

in AS we had a whole chapter for making graphs

unique zodiac
#

yea but u dn need to make a graph here

#

Okay tbf if it does help u then its fine

#

But b careful and see if graphs are an accepted form of working

blazing wraith
verbal nova
#

is the derivative at x = -4 0?

#

no its infinity ooof

unique zodiac
#

So bcuz dy/dx = 1/(x+4)^1/3 * (5x+12), we can see that if the denominator is zero, the derivative wont exist

So this only happens when (x+4)^1/3 = 0, x = -4

#

Its a little tricky to explain, but bcuz u can show that at x=-2.4, we expect the y-values around it to be more than f(-2.4) right?

#

But somehow f(-5) is less than that, so that means that there is a turning point that we didnt find, OR there is a discontinuity in the gradient

#

In this case, we find a discontinuity and the point where the gradient is discontinuous will be a max/min

#

In this case its a max.

#

I hope that helped, this q is a bit big brain if ur doing it strictly w/o graphs

blazing wraith
#

ohhhhh

#

thank you so much!

unique zodiac
#

u get it now? based

blazing wraith
#

lemme digest, but i should be able to get it

#

means discontinuity gradient will also be either max and min

#

right

unique zodiac
#

I meant that it could possibly be a max or min, it depends on the circumstance

#

As I said its a little difficult to explain

unique zodiac
#

Its important to consider gradient discontinuities

blazing wraith
#

yeaaa thank you again @unique zodiac

idle rainBOT
#

Gave +1 rep to ukan#9821

stuck rapids
#

Hi guys xD does anyone know how to approach this question for Tp M subset.. This is the second part of the question.. M is a vector space for 2 × 3 matrix in this case

The thing for me is.. the AP=PA condition doesn't make sense to me cuz AP= 2 by 2, while PA should be 3 by 3

I also thought of alternative approach like A=P^-1PA, but since neither of them is a n by n matrix, this won't work

vestal swift
#

why here so quiet :(

#

also found this in a coding textbook but i'm curious about the maths approach to it :P

idle rainBOT
#

Help needed <@&597104882482413589>

quasi sequoia
#

Let's say you have vector u v and w. u=(-1,2,0) v=(4,1-3) and w=(10,-2,-6). How do you know when to use Gaussian elimination to find if they are dependent or independent

unique zodiac
#

If A is 3x3 then AP = 3x3 matrix and PA = 3x2
Hmm thats odd

unique zodiac
#

Its not like u need certain criteria to use gaussian elimination

#

You can apply it on any 3 vectors to see if they are linearly dependant or not

quasi sequoia
#

oh ok, thanks

unique zodiac
stuck rapids
#

Ap=PA is clearly unsolvable? They can't be equal?

quasi sequoia
#

Can anyone explain how vectors u = (4,-3,0) and v = (5,0,2) are coplanar, they are not on the same plane, one has a z value, but Ive been told that 2 vectors of R3 that are brought back to the origin are always coplanar. What does that mean?

idle rainBOT
#

Help needed <@&597104882482413589>

tawdry gull
#

But thats not the main focus of the question

stuck rapids
#

But to show that Tp is closed under addition.. Oh wait ya

tawdry gull
#

jia you

#

u can do it

stuck rapids
tawdry gull
#

😩

stuck rapids
#

I think I got it.. But it has to satisfy that condition given isn't it

tawdry gull
#

mhmm

stuck rapids
#

Hmmm

tawdry gull
#

||(A1+A2)P=(A1)P+(A2)P=....||

stuck rapids
#

Owhhhhhh

#

🫣Now it makes sense danggg

stuck rapids
tawdry gull
#

:)

stuck rapids
#

@rancid schooner and u didn't give any tips before hahahaa

#

🫣

rancid schooner
#

Because πerrot would come up with a good answer 😄

stuck rapids
#

U would too

#

🫣

rancid schooner
#

still learning :)

stuck rapids
rancid schooner
#

Machine learning 😄

stuck rapids
rancid schooner
#

Put it in front of a mirror

stuck rapids
#

Nice joke

#

😂

unique zodiac
unique zodiac
vestal swift
#

If it's not then one of the axioms must fail right? (First axiom in this case)

#

Since Tp is a subspace iff it satisfies the 3 axioms isn't it 😭

ebon rose
#

can someone help with this one

stuck rapids
stuck rapids
rancid schooner
#

Please do a study session for university matrix maths

stuck rapids
#

Due date in 6 mins

verbal nova
#

Is b a function?

brazen rampart
#

can you help me figure out what i did wrong
the actual answer based on the solution sheet doesn't have the /e^t but i don't see how to negate that

tawdry gull
#

functions need to be

  1. defined in the domain
  2. has only one output
tawdry gull
#

for x =/= 0

verbal nova
#

Ok so a function has an output for all values in the domain

tawdry gull
#

yes

#

and it can only output 1 value

verbal nova
idle rainBOT
#

Gave +1 rep to The_Pierrot#7889

young marten
#

one to one or many to one

#

only

late frost
#

wait

#

math & phy combined ?

verbal nova
#

Yes, they the same

stark wave
#

so is philosophy

late frost
#

so No Phy role?

stark wave
#

There's a UG physics role but they both lead here

late frost
#

ah

#

IC 👀

verbal nova
# stark wave so is philosophy

XD i was have a friend who took philosophy elective their beginning syllabus was so similar to logical propositions in Discrete Meth

#

All mathematicans are philosiphers but not all philosiphers are mathematicans

verbal nova
#

Is the inverse function even possible???

idle rainBOT
#

Help needed <@&597104882482413589>

verbal nova
#

I assumed there was and got [1/3, 2/3)

#

But now im wondering if it is injective or even surjectuve

jagged quarry
#

Needs to be solved using matrices

#

How to do this using matrices?

idle rainBOT
#

Help needed <@&597104882482413589>

late frost
long aurora
late frost
long aurora
#

But u werent able to solve an AS trig question yesterday…

late frost
#

cuz trig is said less
not a lot

#

only basic he said

#

@long aurora u were guys like made me confused

long aurora
#

I see

late frost
late frost
#

$\frac{d}{dx}e^{tanx}=$

round sirenBOT
#

Unknown Member

idle rainBOT
#

Help needed <@&597104882482413589>

late frost
#

what's the answer?

main topaz
#

$e^{\tan x} \sec ^2 x$

round sirenBOT
main topaz
#

The derivative of $e^{f(x)}$ is $e^{f(x)} \cdot f'(x)$

round sirenBOT
late frost
wary jungle
#

btw do you guys have any youtube channel recommend for discrete math? Also help my peanut brain xD I think c and d is equivalent but I am not sure about the rest (Question 4)

verbal nova
wary jungle
#

nice same as the answer I chose 0.0

#

does a,b and d works too?

verbal nova
wary jungle
#

oo ok

stuck rapids
#

I have a question xD.. Is there a way to compute the determinant of 6*6 stochastic matrix?

#

I have to prove that the eigenvalue is 1,since a stochastic matrix should have an eigenvalue of 1 and have a stable distribution

tawdry gull
#

all the best 🙏

#

row operation to the matrix would help

rancid schooner
#

Interesting topic

#

Please host a study session and share what you have learnt

stuck rapids
rich wraith
#

which axiom justifies that if x = 1 then x + 1 = 2?

#

or in general which axiom justifies 'doing the same thing to both sides'

tawdry gull
#

field axiom

rich wraith
idle rainBOT
#

Gave +1 rep to The_Pierrot#1126

stuck rapids
blazing wraith
#

how to do 1b

idle rainBOT
#

Help needed <@&597104882482413589>

blazing wraith
#

i need help plssss

rancid schooner
#

It’s greater than the integral of x² from 1 to 3 which is 26/3.

blazing wraith
#

i dont get it, can you elaborate further, by using the theorem pls @rancid schooner

rancid schooner
#

From the graph in part a the √ graph is above the x² graph. So its integral cannot be less than the integral of x².

blazing wraith
rancid schooner
blazing wraith
#

yeah so??

#

i knowww then??/

blazing wraith
#

neverminddd

#

i got it

wary jungle
#

Can anybody explain what does Y means?

verbal nova
#

Set X is the domain

#

Set Y is the range

tawdry gull
#

Y is the set of words using the english alphabet

#

doesnt have to be english words

#

it can be "aksdghasjgkdash"

#

thats also in Y

#

the point is that it's non-null

verbal nova
#

ohhhhhh

wary jungle
#

Oo ok got it thank you!

wary jungle
#

Can anybody help? I don't get this 2 questions

rancid schooner
#

Q6: int(1000/7) + int(1000/11) - int(1000/77)

wary jungle
idle rainBOT
#

Gave +1 rep to AlexV#1811

rancid schooner
#

😊

wary jungle
#

Guys, may I know why f(x) is not onto? |B| <= |A|

#

I thought it should be

#

Or f(x) should be integer? And not N?

tawdry gull
#

f doesnt map to all the naturals

#

a quick example, there is no such x in N such that 3x-2=2

#

2 is in the Naturals, yet we cant find a natural number x such that 3x-2 becomes 2

#

so it is not onto

minor schooner
tawdry gull
#

yes exactly

minor schooner
idle rainBOT
#

Gave +1 rep to The_Pierrot#1126

verbal nova
#

https://www.youtube.com/watch?v=ngCos392W4w
I highly recommend this video for problem solving, I used this videos techniques yesterday by testing out multiple cases and finding a pattern in my discrete math exam in a question that is not even related to recursions

In this video, we take a look at one of the more challenging computer science concepts: Recursion. We introduce 5 simple steps to help you solve challenging recursive problems and show you 3 specific examples, each progressively more difficult than the last.

Support: https://www.patreon.com/reducible

This video wouldn't be possible without the...

▶ Play video
blazing wraith
#

i need help with this

idle rainBOT
#

Help needed <@&597104882482413589>

rancid schooner
# blazing wraith

Volume = Cross sectional area multiplied by distance travelled by centroid

rancid schooner
#

Hopefully this is not true

vestal swift
#

Math gods

#

How y'all do dis

late frost
#

math error 😭

young marten
#

perving out on a book ffs

verbal nova
rancid schooner
#

Add (2-√3)²⁰²² then subtract 1 to get the integer part.

rancid schooner
#

To find the first digit to the left of the decimal point, first let 𝛼 = 2+√3 and 𝛽 = 1/𝛼 = 2-√3.
Note that 𝛼 and 𝛽 are roots of x²-4x+1=0.

#

Is that enough of a hint?

#

Would you like me to continue?

vestal swift
rancid schooner
#

Will put the rest in spoiler below.
||Let Sₙ = 𝛼ⁿ + 𝛽ⁿ, and note that Sₙ = 4Sₙ₋₁ - Sₙ₋₂, and S₀ = 2, S₁ = 4.
Computing Sₙ mod 10 iteratively for successive values of n shows that
Sₙ mod 10 = [2,4,4,2,4,4,2,4...] for n=0,1,2,...
i.e. Sₙ = 2 if n=3m, and 4 otherwise. Since 2022 = 3(674), therefore S₂₀₂₂ mod 10 = 2.
Also, since 0< 𝛽= 2-√3 <1, therefore 0<𝛽ⁿ<1.
Hence the digit of the left of the decimal point is 1. ||

rancid schooner
#

Extra credit: What is the digit to the right of the decimal point of (2+√3)²⁰²²? 😄

vestal swift
#

Why mod 10 though?

#

And the beta thing, since we're calculating alpha^2022 right 😢

rancid schooner
vestal swift
#

But S_2022 is α^2022 +β^2022 right? How does dividing by 10 give the left digit next to the decimal point of α^2022?

rancid schooner
#

α^n on its own is messy so we pair it with β^n to get an integer which is easier to compute

rancid schooner
#

We know α^2022 + β^2022 is an integer. So the integer part of α^2022 must be 1 less than that integer.

vestal swift
#

Oh so something like finding the floor value of α^2022 ah 😂

rancid schooner
#

Well the floor is the integer part :)

#

the integer part is lava 😄

vestal swift
rancid schooner
#

Your calculator is unlikely to be able to handle that haha

vestal swift
#

And coz the beta thing gets closer to zero for higher powers of beta :D

rancid schooner
#

Have you read my spoilered solution?

vestal swift
#

:(

#

Thanks math god 🙇‍♀️🙇‍♀️🙇‍♀️ @rancid schooner

rancid schooner
#

😊

vestal swift
#

Wait no rep point thing?

#

Hahah

rancid schooner
#

Haha maybe they removed it or perhaps you have to reply

vestal swift
idle rainBOT
#

Gave +1 rep to AlexV#1811

rancid schooner
#

😊

#

No no for that you would need @tawdry gull 😄

vestal swift
#

Yes both of u 😭

#

I had to retake foundation of maths coz my midterms score was below avg 😭😭

rancid schooner
#

Which topic is this question under?

vestal swift
rancid schooner
#

That’s ok. That means you’ll have a stronger foundation :)

#

You’re not taking discrete maths?

vestal swift
#

MH1812 ahaha

#

Next sem

#

Different code

#

MH1301

rancid schooner
#

Looks like a flight number

vestal swift
vestal swift
rancid schooner
#

Did your friend solve it?

vestal swift
#

Still waiting for their reply ahaha

rancid schooner
#

Why are you doing your friend’s exam even though it is over? For practice?

#

Presumably exam means in-person exam.

#

Anyway hope that was helpful :)

vestal swift
vestal swift
rancid schooner
#

Now try the extra credit part :)

vestal swift
#

:(

vestal swift
rancid schooner
rancid schooner
#

The 2,4,4?

vestal swift
rancid schooner
vestal swift
rancid schooner
#

Don’t think that’s even necessary

vestal swift
#

So how to go about proving it ah :(

rancid schooner
#

f(2,4) = 4
f(4,4) = 2
f(4,2) = 4

#

That should be good enough

rancid schooner
vestal swift
vestal swift
idle rainBOT
#

Gave +1 rep to AlexV#1811

vestal swift
#

😂😂

rancid schooner
#

It was a fun question 😄

rancid schooner
#

Here’s an idea. Why don’t you do a reverse study session? You livestream your attempt and then people can give suggestions.

vestal swift
rancid schooner
#

You can just ask for suggestions for the next step

late frost
#

is Limits done for u guys?

vestal swift
late frost
vestal swift
#

How to even get this role 😂

rancid schooner
#

dQ and Sasuke are friends?

rancid schooner
late frost
tawdry gull
#

@rancid schooner

#

very interesting question

rancid schooner
young marten
#

no way out of all people you find smthn tricky

verbal nova
tawdry gull
rancid schooner
tawdry gull
#

No thanks 🙏

late frost
#

😂

minor schooner
#

What are engineering qns like 💀😭

tawdry gull
#

Medical ones are the hardest

#

Harder than math major’s even

rancid schooner
#

Mathematical Medicine

minor schooner
verbal nova
#

Bayes theorem and combinatrics and shit

tawdry gull
#

U dont want medical students who couldnt think properly under time pressure dont u?

tawdry gull
verbal nova
tawdry gull
#

:v

upper socket
#

hey

#

do you guys know where can i find university physics book by young and freedman

rancid schooner
#

young and free physics 🤔

#

@tawdry gull studies physics at university as well?

tawdry gull
#

required course 🤷‍♂️

rancid schooner
#

Just think of it as applied maths.

#

Experimental as well?

tawdry gull
#

yes

rancid schooner
#

Yes to experimental?

tawdry gull
#

we have experiment course for it too

rancid schooner
#

Interesting

idle rainBOT
#

Help needed <@&597104882482413589>

wary sluice
#

Basically, I've done A levels and started undergrad maths

#

They got something like let's say MATH A and MATH B

So MATH A I exempted since I did a levels and I am on MATH B

#

Math a was the prerequisite for MATH B and it seemed to just be A levels

#

....

#

To get to the point

I've done integrals

#

Buts what's this thing with E and then n --> infinity????

#

By E I mean the sigma sign

tawdry gull
#

Sum to infinity?

#

Probably talking about riemann sums

rancid schooner
#

He’s probably referring to the epsilon-delta definition of a limit.

verbal nova
vestal swift
#

just need a small hint w this :') @mathgods

rancid schooner
#

Triangle inequality

vestal swift
#

Yea thought of that too but like I think something’s off here, idk how to get there

tawdry gull
round sirenBOT
#

The πerrot

vestal swift
tawdry gull
#

or u can use the fact that $-|f| \leq f \leq |f|$

round sirenBOT
#

The πerrot

vestal swift
tawdry gull
#

just integrate all sides and conclude into one single inequality

vestal swift
#

but how to move the modulus outside tho

#

for the lhs

tawdry gull
#

u dont

#

u take modulus of all sides

#

lol

#

after u integrate

vestal swift
idle rainBOT
#

Gave +1 rep to The_Pierrot#1126

stuck rapids
#

Calculus

#

Horrible

vestal swift
vestal swift
vestal swift
#

and just say approximation? idk sounds weird tho

stuck rapids
tawdry gull
vestal swift
tawdry gull
#

f can be negative?

vestal swift