#math-help
1 messages · Page 46 of 1
can someone help me with this question
2 = log3(9)
Therefore the initial equation is
log3(x+4) - log3(9) = log3(x-4)
Which is equivalent to
log3((x+4)/9) = log3(x-4)
Since the logarithm function is injective
log_a(x) = log_a(y) implies that x=y
Therefore
(x+4)/9 = x-4
I leave the rest for you to solve
<@&717391911132069929> I think this is a scam link? It's weird at least
its the real deal, just gonna delete it anyways because we dont need this kind of trolling
it isnt its just discord guidelines link
Yeah but what's the spam for ? 🤨
Add the number of parts 6+1=7 parts.
Those 7 parts will equal 637mL
To find out how much one part is, do 637/7=91 ml for one part.
Ratio of water:lemon juice is 6:1. So do 6 x91=546 ml of Water
PROBLEM SOLVED I was forgetting the first x on the RHS was also beneath the square root hehe.
Q 10b pls srry for image rotation
Is d(x, 2) defined as |x-2| ?
Because if not we need more details about the function d
could anyone please explain to me why this R^3 -> R^2 associated matrix is surjective, but not injective ?
Because of the two identical columns
Because the matrix applied to (0, 1, 0) and (0, 0, 1) would return the same output vector (1, -1) , even though the input vectors are different
Reminder :
The matrix M is said to be injective if and only if :
Mu = Mv implies u = v
Start off by identifying what kind of quadruples could be the constant coefficients of the fraction, then move on to the powers of x and y
Think deeper
The quadruple 1 2 3 6 could work because you could create 2/1 and 6/3 with them, which are equal
You're looking for equal fractions
yeah so wouldn't 2/4 wrk?
2, 4 is a pair, not a quadruple
Yeah
Once you've made a list of all possible quadruples for the constant coefficients, move on to all the sets of 3 numbers that could go as powers of x
(They'll be the same for y)
y 3 numbers
Because there are 3 powers of x involved in the equation
You're looking for these powers so you need 3 values
Once you've listed all valid combinations for the constant coefficients, the x's and the y's (which are the same as the x's) just pick a combination of one quadruple and two 3-digit-long sets so that you end up with 10 different numbers in your final set
yeah imma answer the question then if u r free u can see if correct
@ember kernel
these r all the possible coefficients
i found
1/2, 3/6
.
2/4, 4/8
.
1/2, 2/4
@ember kernel if ur availiable sir could you please explain q10 b to me
All pairs equal to 2 :
2/1
4/2
6/3
8/4
10/5
All pairs equal to 3 :
3/1
6/2
9/3
Quadruples can be made from combining pairs
Regarding x, you have all the triples : m, n, (m-n)
(same goes for the y's but with different values)
okayy thank you so much!
P(X <= x) is defined as the area under the density curve from -inf to x
np :D
damn thats ur choice...but i think u shud do them urself...but thats just my opinion
bro ur not gonna learn anything lmao
Sorry for disturbing, how to solve cosh x -3 sinh y = 0 and 2 sinh x + 6 cosh y = 5 ?
Rule #5 of this server #welcome-verification
hi, i have this reduced matrix and I'm asked to find (x,y,z) such as T(x,y,z) = (0,0,0).. What exactly am I supposed to do ?
considering this is the answer:
you have to find a vector that if multiplied to the matrix T the product=0
but how does the result give us 0 ?
wdym
matrix product is different from product between scalars
two matrixes multiplied by each other can give 0 as a result even if one is not 0
yes, but i don't see how we found this result
like what steps did we take, it's confusing me
sorry if i'm being confusing
can you do the product between a matrix and a vector?
yes
ok so
when i put the multiplication into a system, i obtain: x = -14/5 z and y = 8/5 z
and i don't know how we go from here
ohh okay then what about the "s" in front of the vector that's any real number ?
yes because whatever s is the result doesn't change since s is a scalar
if z was a fixed number, and not any number we choose, "s" wouldn't exist right ?
no, s would still be there
since s is a scalar, it's commutative for multiplication, so we can imagine we put it before the matrix
and the product between the matrix and the vector is 0
so no matter what s is
if we multiply a scalar by 0, the result is always gonna be 0
okayy i get it now!! thank you ^^' you always explain things really weel
np
pour la premiere limite (celle en 2-) ca représente le taux de variation en 2- et donc la pente de la demi-tangente en ce point. si tu fais le calcul tu devrai avoir -2 je crois
la demi tangente est déjà representee sur le graphique dc ta juste a calculer sa pente
Pour qu’elle soit la pente de la demi tangente il faut que f(4-x) soit f(x) non ?
oui mais ici ca revient au meme
Comment je trouve f(x) à partir de f(4-x)
puisque f(4-x)=f(4-2)=f(2)
tu n'as pas besoin de lexpression de f(x)
honnêtement g tjrs pas trouver
Ahh merci en tout cas
je crois que tu peux remplacer f(2-h) par f(-1) pour trouver la pente en -1 mais je suis pas sure que ce soit ca
de rienn
tu pourrais m'envoyer tt la donnee de cette fiche s'il te plait ? ca pourrai etre un bon entraînement pour moi 😅
merci beaucoup !
Derien
x=-14/5z and y=8/5z
<=> there exists s€R such that : z=s and x=-14/5 s and y=8/5 s
basically we have total freedom in our choice of z so we say that z can be any scalar s, and we express x and y en fonction de ce scalaire
thank you!
hey i rlly need some help with this can anyone help me?
guys i need help
I might be able to help what do you nee to know?
I’m assuming on the left side of the chart you write the name of the expense (ex. Spotify) and on the right side of the chart you write the amount it costs (ex. $10) then you sum all of the numbers (add them together) for the total amount
Since there is only one source of income the total will be the same as the one income
Sorry I’m not sure if this is helpful I understood why you’re confused. What does her having to save for a car have to do with it?
In terms of x and y only?
Is there another part to this question?
any physics or eng ppl that can help
this was a lil bit spicy compared to the problems I solved already
Where did I go wrong with my integral ( in the red) the answer is meant to be 25/3
can anyone explain me strain on the rope? (ik it's physics)
tension force (clue use horizontal and vertical components)
no like the definition
I understood the other parts
but the strain part I don't know
ok hold on ill explain once i help the user with part d
oh lmao nvm i understood my mistake smh
This one can you send me the question or the question is there in the pic itself
probability?
yep
I didn't touch probability yet but I know a bit of integration
i can send u some hard integrals lol
Send one just for fun
Idk if I can solve it
ah ok
Easy one
Isn't it the other way around
if a car would go up a hill frictional force increases as the angle of inclination also increases
they are not inversely proportional to each other
No
You know that a car slips when it goes on a steep incline right
Also on a flat road friction is maximum
oh yeah ur right
bro we talked about this
im kidding its a confusing topic
want me to explain again?
can someone tell me how can I calculate the determinant here T.T the determinant is 1 * 3 * 5 * 7 i'm pretty sure but then...?
You probably have to solve it the long way ,but I can't see why any book would ask this.
you mean by calculating minor matrixes ?
yes
nothing its just a story
yes
Send that
variable expenses?
idk
I mean it seems simple
Fill in the details
whats variable expenses
Idk too
wud that be like spotify
since its like how much u use it?
cuz its like a monthly subscription...the variable wud be a month
I guess it's more like when you don't know how much you are gonna spend on something every month or like when you suddenly have something extra you need to spend on
metal removed while machining one hole will be just the volume of one cylinder hole
the total volume after machining 4 holes will be vol(cuboid)-4(vol(cylinder hole))
so for b it would only be the volume of the cylinder?
ok thanks
for the 1st three years it is simple interest
so use PxRXT/100
and take that amount as the new principle for the next 5 years and apply the compound interest formula
thats...kinda the formula for simple interest
since r is a %age
also, add the original principle rate to the simple interest rate
?
3000?
its 4.5 per CENT
per cent means divide by 100
add that to the new found prt/100 value
oh yeah ofc
yea that alone is the interest, so now add the original 3k
yep
and that new amount is your input for the next 5 yrs of compound interst
bruh
okay we still have hope
cool lmao
i cant understant computer language but it looks correct
so yes
that is p+( 1+r/n)^nt right
idk thats what the teacher gave us
how wud u write it
the answer you got after 3 years
that is your new "p"
yeah thats correct
A will be your final answer
p is yoour amount that u got after 3 yrs
r is interest rate
t is 5 yrs
n is the number of times you apply the interest rate, in this case its 5 (cuz 5 yrs)
wudnt it be 8 including the previous 3 yrs
i will be included
so its 8?
no since the comp interest only for 5yrs
yeah right here
but n and t are powers at the end
what does that mean
and since compund interest is also a percent wudnt we devide by 100
take n=1
since it is compounded only 1 time in each year
if they say "compounded half a year annually" or something like that you will have a diff n value
when studying about derivatives i got these two formulas, i don't understand what 'a' stands for, if it's just the name of a variable then both formulas apply to the same thing?
(x^n)′ = nx^(n−1)
(a^x)′ = (a^x) ln a
in the first case you are diferentiating (x itself) with respekt to (x)
i don't understand
d/dx (x^n) is nx^n-1
d/dx (a^x) isnt the same as this
here (a^x) is being differentiated WRT x
here (x^n) is being differentaited WRT x
the "a"
i mean you are differentiating x wrt x in the first case
albeit that "x" has a power/exponent
in the 2nd case, "a" is differentiated with x, just that a has the power/exponent "x"
haha thanks for the attempt anyways, i bet that makes sense, just not for me (yet)
lmao no, prolly my bad since i dont study math....i know this stuff from physics so thats prolly why i cant explain it clearly
wait so does this mean a is a constant?
ok nevermind
cuz differentiation of only a constant ist 1
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did you forget to square expected value in task c) ?
Ok so for first one
d(f(x))/d(x)=x^n
Now look at the base of the term
It's x right?
Now consider this
d(f(x))/dx=a^x
Now the exponent is x right?
Here a is another constant which doesn't depend on x
Now let's take this
d(x^2)/dx= 2x right?
What will d(2^x)/dx be?
It's not going to be 2x
ok now let's take y=f(x)=2^x
that means y=2^x (note it's not x^2)
now log(y) = xlog(2)
d(logy)/dx= log(2)
1/y(dy/dx)= log(2) (diff of y w.r.t x)
dy/dx= ylog2
now what is y? It's 2^x
therefore
dy/dx= (2^x)log(2)
now we know that in place of 2 any valid number can come so..
d(a^x)/dx= (a^x)log(a)
(Here all logs are to the base e)
Now you might have heard about the derivative of e^x which is simply e^x again right?
now watch this
d(e^x)/dx = (e^x)log(e)
now we know that log is to the base e
so now what is log(e) to the base e?
It's 1
so it becomes e^x
i dont think so
been a long time since i studied statistics, but i was referring to this
should the answer be (c^2)/12 ?
How I should do this equation? I can't use the calculator to resolve it.(teachers dont let use calculators on the exam)
I already demonstrated that only have one real solution between 0 and 1
I could use bolzano to make that interval even smaller, but I don't think that would be correct
u fking genius, u did it
tysmmmmm
Most you can do is use Lambert W function, that way: X=W(ln(2))/ln(2)
ohh thanks!
np, you're welcome
thank you kind sir with Rick Astley pfp
no problem
can you do a and b?
yes
b idk
am not confident but yeah I can
can u just walk me through
then I'll solve it myself
rt?
are u pertaining to the v^2=u^2+2as?
yeah
It was not?
yep
so what initial velocity was given
then we can assume it's dropped right?
yes
And what does dropping mean
free falling?
yeah
potential to kinetic
uhm yes
ah ok then for a its just potential enrgy asking which is mgh?
yeah
mg(change in h) since they asked change in potential energy but anyways its 3.2m so m(9.8)(3.2)
yep ik that
now m
but for c will I use momentum principle
Is this question a continuation of the previous question you sent?
no it was the same
ok
cuz I was struggling
now we know velocity of hammer and pile since inelastic collision
and we know it goes 0.22m in the ground
so find the retardation and multiply by the total mass to get the resistive force ig?
velocity of the pile was 0 right?
b bruh
9x-2x and 5+1
its equal to - 0.5
because you factorise by sin and tan then you get
sin/tan which is 1 (cz x=0) then you just calculate the rest
I thought we can use sinx/x
yeah i got it....srry for disturbance
np
?
ok. thanks. lim (sin u)/u =1 when u -> 0
like how lim(x->0) sinx/x=1 but nevermind
ohhh i dont think you can use that here since all of the variables are in the form of trigonometric functions
hopital too hard
Yeah hopital is too long
L 'hospital
what is it exactly anyways l hospital or hopital?
L'Hospital's rule is that, if the limit of f(x) := p(x)/q(x) at x = a is an undefined form (= 0/0) then the limit of f(x) at x = a can also be expressed as p'(a)/q'(a) to avoid the 0/0 thing
Example :
Ohhh ok
sorry to bother
It depends on your language
well my sir uses both interchangeably
In some language they translated it by removing the s I think
mhm
But the spelling doesn't matter, as long as you understand/are understood when speaking about maths
Yeah
are u makinus solve ur assignments?
lol what
its homework
but since covid its online
im just new to this
like she didnt even explain
can u explain?
its cuz i skipped the questions i didnt understand
and came back to them
theres 25 quesions im done all except 3
answer is 4 number
is that for me?
yes
so the fourth option?
ye
but can u explain how
now go ready theory ill not answer more
ill try
- Assume x = a + bi and y = c + di
- Use the first equation to derive a formula for either x or y
- Combine the equations so you only have one unknown
- Then substitute that unknown with the expression from 0.
- Continue to find the other unknown
idk if im allowed to help @quaint imp
ok so first you find out the slope of the given equation.
Then since the other line mentioned is parallel it must have the same slope
Now use the point-slope equation for a line
y-y1=m(x-x1)
where x1 and y1 are the coordinates of the given point
And now just put in the values and you are done
all of it? @somber reef
Does anyone have any good calc 2 worksheets, specifically integration by substitution, and with answers.
like hard q
yeaa teach mee aaa :')
The question c is straightforward
P and Q are the roots of the equation and so p+q=-(-8) which is 8/a
And pq is c/a so answer is 8/c
the first part I guess the answer is [p,q]
second part you can maybe do a=c/pq?
VECTORS A, B, C DIFFERENTS FROM ORIGIN ANGLE BETWEEN A and C = angle B and C, find "t" to C⊥D = ||B| | A+tB
anyone can help me? 😦
I can't understand much from the language, but here is what I can tell you:-
As D is ||B| | A+tB, thus D lies in the plane of A and B, and as C⊥D, that means C is perpendicular to the plane of A and B, thus it is perpendicular to A and B.
The angle between A and c= angle between B and C and as angle between A and C is 90, thus angle between B and C is also 90., which we already know.
So, C⊥A and B and D.
I don't know what to do after this, some detail which I can't read in that.(I don't know Spanish)
If the question is asking for the value of t, then any value of t is possible.
...
Here's in Spanish(using google translate):-
No puedo entender mucho del idioma, pero esto es lo que puedo decirte:
como D es ||B| | A+tB, por lo tanto, D se encuentra en el plano de A y B, y como C⊥D, eso significa que C es perpendicular al plano de A y B, por lo tanto, es perpendicular a A y B.
El ángulo entre A y c= ángulo entre B y C y como ángulo entre A y C es 90, entonces el ángulo entre B y C también es 90., que ya sabemos.
Entonces, C⊥A y B y D.
No sé qué hacer después de esto, algún detalle que no puedo leer en eso. (No sé español)
i have a matrix determinant evaluation question can someone help me
for improper integral what do i do when i evaluate teh limit subbing in infinty on top
cause ik if its in the denomenator then its zero
Anyone knows how to do this?
@cosmic mountain
You can simplify the denominators
If anyone sees an arithmetic mistake please point it out though i think it should be fine.
can someone please help me with this?
Yeah that’s right
Whoever needs a math help, come Dm me or ask here
Thank youu!
hi there
can u help?
so <DAE= <ADE = 75
Angles in a quadrilateral = 360
360- 75-75=210
<ABE+ <BCD = 210
<ABE= <BCD therefore <ABE + <BCD = 2x
therefore 2x= 210
x= 105
i think thats right and i hope that makes sense : )
: )
omg. 10q~~
np anytime
there is no angle ADE??
where is angle ADE?
She meant DAE
ahh
but can you please explain how theyre equal? sry havent done math in a while
abe isnt an angle too right
but is that given? or is there some postulate?
ADF even sorry
ABC for that one
ah
i think there is a thing in regards to circle theorem but i havent done math in a couple months, cant remember
is the theorem anywhere related to the two chords being parallel?
If so then the angle can be 105
i havent done math in 2 years 💀💀
bruh if the cords are parallel then we can just find the corresponding angle and subtract 180 (angles of a line) and direct we get 105
so maybe thats it
Yeah
But thing is I wanted to know whether such arrangement of circles and lines would result in parallel chords
exactly, we cant assume AD||BC....there must be something to prove that
Yeah
If we join FE then that creates 2 cyclic quadrilaterals
Now we know opposite angles add up to 180
So that means <FEA is 105° and FEB is a supplementary angle to angle FEA therefore <FEB is 75°
Now we apply that property that opposite angles in a cyclic quadrilateral adds up to 180° and we get angle FCB as 180-75 which is 105° hence proven
we just can't assume that the angle ADF is 75°
oof lmao
where is angle fae?
that still doesnt make fae
FEA
yeah
my bad sorry
yeah nvm
Edited it
We learnt it in 9th grade
lmao yeah, cyclic quads and stuff
yeah
if i were in 9th/10th, id be able to solve this easily.....i havent touched math in 2 years 😭😭
I haven't touched this type of geometry in 2 years
we currently learning 2d and 3d coordinate geometry
sure where do u need help
Can someone help me find the volume of a cube with a surface area of 24a^2?
Thanks, i have trouble identifying the translations, scale factors, etc between 2 different functions
find the value of one side
and the volume of a cube is = (side^3)
was that a joke question?
do u have concerns about a specific question or just those concepts
Here i'll send a picture of the problem in a bit
Anyone knows what this symbol means ?
Need context. I'm pretty sure it's an unconventional ln
judgemental
No lol it’s from a SAT practice test
But how exactly do I find the value?
so surface area of a cube is given by the formula 6a^2 where "a" is a side
ah i see, thank you for telling this....sorry if i came off as rude
so basically, if 24a^2 =6(side)^2 then "side" will be equal to sqrt(24/6)------> is basically 2a. Since "side" is 2a, the volume is (side)^3 and hence it will be 2^3 = 8 a^3
In the question, surface area should be 24 only but he/she has written 24a^2 and this makes it confusing
yeah, thats why i didnt write the units
regardless, the answer becomes 8a^3 if the area is indeed 24a^2
lmao i didnt use the "a" in my initial answer as i gave them the formulas as 6a^2 and a^3 for surface area and volume respectively
so if i used the same "a" for the formula and what is given, the op might have gotten confused looking at how is 6a^2=24a^2.....thanks
Yup this will confuse anyone cuz you can clearly see that a^2 can be cancelled out in this equation
yep
hi, i got some trouble in normalize the vector. In picture you can see that second table is aggregate of first table but the third table idk how they normalize the vector
Anyone can help me ty
Divide each cell of the vector by the total sum of all of its cells
Thats gives :
total = 18 + 12 + 2 + 16 + 10 = 58
normalised cell #1 = cell #1 / total = 18/58 = 0.31
normalised cell #2 = cell #2 / total = 12/58 = 0.21
normalised cell #3 = cell #3 / total = 2/58 = 0.03
...
That's how you normalise the vector
I see. Ty for your explain
why does P(Z<-a) = 1- P(Z≤a) explaining through symmetry of standard normal graph
A standard normal graph is pair. Therefore we get formula [1] : P(Z >= b) = P(Z <= -b)
That works for any b. Here's we'll use b = -a
Using one of the probabilty-related identities, you calculate :
P(Z < -a) = 1 - P(Z >= -a)
And using formula [1], you can prove it is equal to 1 - P(Z <= a)
tyyyyyy
hey lads, can anyone help me with this
first for its position put the value of t=1, second for velocity find its dx/dt or derivative and then put the t=1
answer position= 5units velocity=-1 units
Chain rule
dg/dv = dg/df * (df/dx * dx/dv + df/dy * dy/dv + df/dz * dz/dv)
Evaluates all expressions (x, y, v, dx/dv, ...) at (u,v) = (-1, 2)
All the necessary values are given
Correct me if I made a mistake pls
U right, thx!!
hi guys, how are you? I'm Giorgio, 15 yo and attend the second year of high school in italy. I don't understand analytic geometry, we are doing the first things, could someone help me. Thanks
does anyone know how to solve this?
i am not sure if i am right but
sin 2theta = 2 sin theta cos theta
therefore if you expand the equation, 3x2sin(theta)cos(theta)+cos(theta)=0
6sin(t)cos(t)+cos(t)=0
factor out cos(t), cos(t) x (6sin(t)+1)=0
you will have 2 equations, cos(t)=0 , 6 sin(t)+1=0
guys, can anyone help me about solving that? I couldn't solve it
x=5 y=6
thank you
how tho kinda stuck at the equation when i sub y=31-x^2 , y^2?
thanks but if u can, explain how pls
ya same
i just did trial and error
like i guessed that x squared would be like 25
and then 31-25 is 6
and then that would mean that y squared is 36
if that explains it lol
i just guessed
because for 31 the lowest square you can have is 25 without going over 31
substitute y = 31-x^2
lets say that (-x^2+31)^2 and we expand it
(-x^2+31)(-x^2+31).....
yep
it becomes x^4 - 62x^2 + x + 961 = 41
nope im tripping my bad
there is 3 different degree xs, so I think there must be another technique. Solving with matrice maybe?
was this a question or a problem lead you to this?
nah its a=b x a-b
noo you wont have any x^2 term
No, this is a plain question.
i mean no 62x^2
?
i agree tho
check again buddy
MY BAD
yup
a^2+2(a)(b)+b^2=(a+b)^2
haha we got different method but ultimately i got this too
from here what to do?
factor out??
sry my bad
its fine amigo
no idea
oh well, cant help ya much
idk if this helps but you can think it as the intersection of 2 parabolas
"The intersection points of a vertical and horizontal parabola lie on a circle whose centre's distance from the directrices is the sum of distances of the foci from the directrices (in both the x and y directions."
rn i don't know why this works but it should
any of you can plz help me with that?
i have to find the points M with an affix z that verify this equation:
|3iz + 6| = 3|z - 1 + i|
ive been trying to find it but im finding something weird i dont think it's correct
wdym poitns M with an affix z? also what's z? is it a complex number?
also M points of what
M(z) with z=x+iy
ok, what did you do so far?
i tried to develop it i got
(y+3)²=3(x²+x+8)
that doesnt seem right tho
you can start by saying |iz+2|=|z-1+i| so you have |ix-y+2|=|(x-1)+i(y+1)| , right?
can i do that? i mean the symbol "||" signifies a module
ahhh right omg idk why i got confused
then u just develop?
ull get x²+y²+4-4y = x²+1-2x+y²+1+2y
oh lol that's so simple
thanks! got it. i just thought i couldn't simplify by 3
ehm
je pense que c'est bon j'ai eu ma reponse. merci !
<=> |3i| * | (3iz+6) / (3i) | = 3 |z-1+i|
<=> |z + 6/(3i)| = |z-1+i|
<=> |z + 2i/(i^2)| = |z-(1-i)|
<=> |z-(2i) | =| z-(1-i)|
<=> AM = BM with A : (0,2) and B: (1,-1)
<=> M is in the médiatrice de [AB]
okay
j'aurais dû lire le dernier message oups
hm?
|z(M) - z(A) | = AM
et |z(M) - z(B)| = BM
et en géométrie (pour A différent de B) AM=BM <=> M appartient à la médiatrice de [AB]
ouii mais puisque z est multiplié par i, ca n'inverse pas laffixe des point ?
j'y comprend rien a cet exo 😭
c'est quelle étape exactement que t'as pas compris
dans ce que j'ai fait
quelle ligne
pourquoi ta factoriser par 3i et pas par 3 ?
1ere ligne : j'ai multiplié et divisé par |3i|
ensuite le |3i| au numérateur vaut 3, ce qui s'est simplifié avec le 3 que j'avais au côté droit de l'équation
la raison pour laquelle j'ai choisi |3i|, c'était d'avoir rien à côté du z de gauche
ouii justement c'est sur ca que je bloquais
je pourrais te poser d'autres question sur le même exercice pour vérifié mes calculs ?
oui ?
|-2iz(barre) +4| = |2z +4i|
jai trouver y=1
donc M(x+iy)
et puis ya
|z(barre) + 4 + i| = |3+4i|
j'ai trouver
(x+4)² + (y-1)² = 25
donc M appartient au cercle de centre A(-4;1) de rayon 5
j'aurais dit y=0
notamment si tu remplaces z par i dans l'équation, ca donne 2=6
par contre si tu remplaces z par 0 (ce qui vérifie y=0) ça marche bien : 4=4
donc j'en déduis que "y=1" est faux, et que "y=0" pourrait être juste
(d'ailleurs je suis sûr de y=0, mais je voulais te dire que c'est un bon réflexe de vérifier avec des cas particuliers quand on trouve une solution)
ensuite pour la dernière equation
c'est correct
ahh oui mercii je reverifierais mes calculs
merci !
non jsuis libanaise mais francophone
ohh
j'ai des potes libanais avec moi dans mon école, ils ont fait prépa au liban
ah bon ? ils l'ont probablement faite là ou je pense moi même la faire
t'es en polytechnique ?
oui comment t'as su
pacque les libanais font pratiquement tous prepa pr finir en polytechnique 😂
ahh
mais jcrois vous avez une arnaque, je pense que vous faites prépa mais que vous passez les concours en filière universitaire (et non prépa), sales arnaqueurs :(
oui c'est ca je crois mais le nombre de personnes prises est largement inférieur a celui qu'ils prennent chez vous
yes c'est vrai, après d'expérience les gens les plus forts sont le plus souvent en prépa (et surtout en MP, moi j'étais PSI), jcrois c'est un bon plan
en tout cas c'est des sucres les libanais que je connais
PSI n'est pas plus ouverte ?
ah ba ils nous rendent fiers alors
tu as fais ta prepa ou ?
ouverte?
sinon PSI y a moins de places à l'X donc c'est pas un bon plan, le mieux c'est PC car y a bcp de places ET tu esquives les génies de MP
sorry for the French spam
how do you integrate question 6? Am I right to put u= In^3t? If yes, du/dx how do I differentiate that
integrate by parts
<@&717391911132069929>
write sin(2x)=2sinxcosx and cos^4(x)=(1-sin^2(x))^2 (since it's square you could also write sin^2-1), then u=sinx, with du/dx cosx cancels out
Consider log t = a
can you post the whole question?
I tried through 1 raised to infinity form but the question is asking me to specifically take l hospital after taking ln of an
so the first thing they use is that if your series converges then its ln will converge as well and the other way around
so by taking the ln of an we get ln(a_n):=nln(n+1/n-1)=(ln(n+1/n-1)/(1/n)
now you can use that ln(a/b)=lna-ln b so we get
ln(a_n) = (ln(n+1)-ln(n-1))/(1/n))
wait
nevermind
taking the logarithm gives you infinity* constant
so it would diverge
Thanks tho , I solve it using U= In t
Exactly but apparently it should converge to 2 ..
ill see how the graph looks
okay it does indeed converge
okay i see my mistake
as n goes to infinity ln(n+1)=ln(n-1)
so this is 0 over 0
and then i think you can use l'hopital right?
sorry for the confusion
derivative is the opposite of integral right?
Ohhh ok I got it now ! Basically take n in the denominator as 1 by n and then apply l' hopital rule right.. thanks for the help!
draw it and remember pythagoras' theorem
you will see it pretty fast then
and one other important point is that in an equilateral triangle the perpendicular line splits the opposing side in two equally long parts
Express the information on the graph in the form of a single equation
For this, do I just extend the line to meet the y-intercept and take any 2 coordinates to find the gradient?
hi i am not sure how do u integrate (sin 1/3x + cos4x)dx
yes
got it.
<@&717391911132069929>
When changing the basis of a matrix. When is using this formula necessary? Isn't it enough to simply multiply said matrix with the changing basis matrix ?
For example if we have the matrix T expressed in the canonical base, let's say [T]_e, and I want it expressed as [T]_b as in the B basis. M the matrix changing basis from e to B. i've done an exercice where all we do is M*[T]_e = [T]_b, and another like this one, where we need to do [T]_b = M^(-1) * [T]_e * M
!purge user AbhiNoe#0857 50
Member "AbhiNoe#0857" not found
its only per channel aaaaaaaaaa
You can also use the fundamental theorem of calculus for this exercice [F(t)= \int f(t) dt]. It’s easier and less time consuming! As you know F’(t)=f(t). For the exercice 6, you have to find the function F that gives you f(t)=ln^3t/t when it’s differentiated. So you know that F(t)=\int ln^3t/t dt and F’(t)=ln^3t/t. Therefore, F(t)=(ln^4 t)/4. And it is the same for the exercice 3. You need to find the function F that gives you exp(x) (1+exp(x))^2 when it’s differentiated. So F(x)=(1+exp(x))^3 / 3.
Don’t hesitate to use the thm when you have to integrate something where its derivative is in it. Here you know that the derivative of ln t is 1/t and the derivative of exp(x) is exp(x).
You need to use the SOH CAH TOA rule. Here you always use the TOA part of the rule which is: The tangent of your angle equals the lettered side divided by the given side.
u=ln(t) much cooler, u deduce t = e^u so dt = e^u * du
and it becomes the integral of u^3 / (e^u) * (e^u du)
= the integral of u^3 du
so u^4/4 would be a correct primitive
which is ln(t)^4 / 4
oh ppl alrdy answered that
Send the question here. Someone will answer
well yes, but A/infinty=0 and 0/A=0 with A a real number
so 0/infinity obviously=0
hey, would anyone be willing to help me with these 3 problems?
Just need a hint on how to approach
Please help
CAN ANYONE HELP ME
Send the question. Someone will answer
Find the surface area of this
I will when I will get my test 💀
What do you mean ?
0.2 × (8+3x) = 0.4 × (3+2x)
A trader buys 30 kg of type A oranges for Rp. 360,000.00 and 20 kg of oranges of type B for Rp. 210,000.00. The two types of oranges are mixed and sold retail per kg. If the trader wants to make a profit of 25%, then the selling price of oranges per kg is ..............
A.IDR 14.250.00
B.IDR. 14,500, 00
C.IDR 15,425.00
D.IDR 15,450,00
Check rule 5 in #rules
anyone? 😭
My bad but I always say smh but dont mean it so dont come at me [and everyone else -_-]
thanks a lot for the explanation !
Formalize in N the following statement:
"If a and b are relatively prime, then there are infinite prime numbers congruent to a mod b”
using the language L = { 1, <, + , . }. anyone ?
does anyone know what epsilon and " | " mean in this pictures?
It's not epsilon, it's a special mathematical symbol that means "belongs to"
And the | is also a maths symbol that means "such that"
Knowing them is a plus, since they are formal symbols
So you could read the last screen as :
"A(x) is defined as the set of all values y such that, for any given x that belongs to the set L, y belongs to the interval between hl(x) and hu(x) included"
The first one is
"L is defined as the set of all values x that belong to [0,l]"
I leave the translation of the second screen to you
Thanks for the answers
I don't know, so I can't know that
I read smh, so I interpret it as smh ¯_(ツ)_/¯
for the second screen, does the flipped A hold any special meaning?
Then,based on what I know,the second screen has this meaning: l is greater than h(x) for any given x that belongs to L.
anyone into this stuff?
Hi! I have this matrix and the eigenvalues are (4,1,1). I'm really confused as to how to find the eigen vectors. I always find something different than the actual answer.
For example, this is the correct answer:
When I replace lambda with 4, I obtain
2x+3y =0
y+z = 0
<=>
x = -3/2 y
y = -z
Yep ! Also ">>" doesn't only mean "greater". It means "significantly greater", which is to emphasize that one is much much much bigger than the other
hey quentin could you please look at my problem, if you know anything of that stuff 😇
anyone? 😭
Sure. Could you reply to the message you sent so I can see where it is pls ?
@ember kernel
Oh yeah that one thanks
I saw it, but I've never been introduced to congruence I'm sorry
no problem, thx anyways
would u somehow know mine?
it’s maths but not maths 🙂
okay nevermind I found the answer, if for some reason someone else is struggling with how to find eigenvectors i can explain
<@&717391911132069929>
If the pentagon is regular then some basic geometry might be sufficient I think. But I'll be honest with you, geometry (just like congruence lol) is one of my weak points regarding maths
when you replace lambda=4 you obtain
000
230
203
so you have x=-3/2y, x=-3/2z, we could write (1.-3/2,-3/2) which is the same thing as (-3,2,2)
thanks, but not that one. i solved it already
^ this one
wdym "a mod b"
modulo
oh ok
The rest of the division of a by b
thank you! but i was wondering, how come the two other eigen values are 1 and 1, yet we are given two different eigen vectors ?
it's 1 eigenvalue that produces 2 eigenvectors
because when you substitute lambda=1 all you get is x=0
so you have freedom with y and z
so you just need to write 2 vectors that are lineary indipendent from each other and the first one and that have x=0
the easiest ones are (0,1,0), (0,0,1)
<@&717391911132069929>
do you have an idea on how formalize that with the given language?
honestly i'm not really understanding the statement
Knowing that p(1) = 2 and p'(1) = 1 and p(2) = -1 how do i write the polynomial on Newton's polynomial (Interpolation)?
Have you seen hermite interpolation, it is newton interpolation in the limit where two interpolation points fall together, then you can use the derivative in that point
does anybody know any resources for vector calculus?
hi guys , need some help here, thanks
<@&717391911132069929>
im so confused
guys I have a concern my prof said that I have to convert it to SI units so there was one question to find the area my ans was right but I wrote it as 10^-7
should have I wrote it as nano or micro?
plz someone respond thank you in advance
the reason why am confuse bcuz its an area but with a diff unit yeah np but hearing me say nanometer squared kinda sounds wrong
100 nano or 0,1 micro
whatever you like
nanometer squared sounds weird tho
wait, squared?
yeah cuz its area
yah i typed it in the calcu they gave me that
I times it with 10^6
to make it m2
the result was 1.25x10^-7
I multiplied it with 10^6
sorry, it's 0,1mm²
SI units
oh so 10^-7 is the same as -6?
if you multiply the left hand side of this by 1.25 you'll get what you want to convert right?
multiply the right hand side too
but what happens if i multiplied it with 10^6
is it still considered as m2?
am getting 0.125
yes
oh ok thxx
hey can anyone help?
i did x^1/2 * x^7/2 = x^4 and x^1/2 * x^1/2 = x^1. therefore x^4-x^1 = x^3, which differentiates to 3x^2. got it wrong tho idk why.
also there's this other question that idek what it means.
i thought it meant the grad = 1. so i do 9-x^3 = 1. solve and it gives -2. but i also got this wrong and idk why.
thanks in advance to whoever helps.
I tried using it and still got it wrong.
you need product and chain rule. think of it as y = x^.5 * f(x)
ye thats what i meant my b
it should simplify to x^3-x = f(x) and also try to keep things on the same side of the equatily sign. you missed that there was a dy/dx on that left side when moving it. As for the second question its giving you the derivative. The rate of change of y with respect to x can be read as dy/dx, so dy/dx = 1 = 9-x^3, and you solve for x.
x^4 - x is definitely NOT x^3
Differentiate x^4 - x and you get 4x³-1
Do not use chain rule here, it's a waste of time
because it's easier to just calculate that the initial expression is equal to x^4 - x rather than multiplying several terms by many square roots, which is very error-prone
mb yea, thats def easier ^ and yea i was wrong, it should be y = x^4-x
quick help why is it not 0
(ok i hope im right this time lol) the derivative of e^t = e^t and d/dx (a* f(x)) = a* d/dx f(x). so the derivative should be the same as your first answer
@tough elk
The triangle inequality is one of the most important mathematical principles that is used across various branches of mathematics. The Triangle Inequality theorem says that in any triangle, the sum of any two sides must be greater than the third side. Learn more about the triangle inequality theorem in the page.
?
i can help u
do u know how a distance between two points are calculated?
use the distance formula
let the coordinates of the point(s) you want to find (x,y)
by the distance formula, sqrt ((x-1)^2 + (y-0)^2)) = sqrt 10
and sqrt ((x-5)^2 + (y-4)^2) = sqrt 10
this is the crucial part
and then you just solve for x and y
two variable equation
Hello can someone answer me the question why there is suddenly a -3? And not a -2?
i think it may be a typo
So it is a mistake by the teacher right?
yep
😅
Thank you!!
I think it's -17/2
Hello there is this -3 again. Shouldn’t it be -2?
My prof is a genius. But he is confused from all his knowledge
You know people who has a high IQ have some struggle with thinking clean?
His classes are a mess. You sit there and he explains and makes many mistakes and suddenly he says things over your knowledge 😂
Can be. But he got professor without learning
You are German?
Exactly. I have to study it by my own
this is parametrics
do you have to do anything before eiliminating t
can u make x = 90 and y = 7.5
Which is the correct answer now?
Feel you bro
this doesnt seem right
what if u find the time
by doing 90/35
and then sub in that for t for x and y
t was 2.97
if u put that in y
u get 7.87
huh
ahaha
i guess so lol
imma have to check that agane with my tutor
its a stupid question
thnx for the help
Can someone explain me how do I get the result 1/6 ln(x^2+2)+c
I do not get the way there
How the heck can be 2/2 there
No left side is the function and right side the answer
oh okay
I need an explanation
I do not understand where the heck this 2/2 come from and then 1/6
WTF?
Yes pls
But if you do 2/2*1/3
It is 1/3
How do you suddenly get 1/6
zanza r u middle school
Uhm
o okay thought ur role