#math-help

1 messages · Page 46 of 1

robust oak
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can anyone help me with this?

robust oak
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can someone help me with this question

ember kernel
# robust oak can anyone help me with this?

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

weary arrow
#

<@&717391911132069929> I think this is a scam link? It's weird at least

trail swift
tawdry girder
ember kernel
#

Yeah but what's the spam for ? 🤨

quaint imp
#

guys i need help

barren wadi
# quaint imp

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

quaint imp
#

ohhhh

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ok

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thank u

shadow kestrel
shadow kestrel
# shadow kestrel

PROBLEM SOLVED I was forgetting the first x on the RHS was also beneath the square root hehe.

wary bison
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i know its easy

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my brain is stuck

left knoll
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Q 10b pls srry for image rotation

ember kernel
#

Because if not we need more details about the function d

atomic dagger
#

could anyone please explain to me why this R^3 -> R^2 associated matrix is surjective, but not injective ?

ember kernel
#

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

quaint imp
ember kernel
# quaint imp

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

quaint imp
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mmm

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like 2 and 4 cud be a constant coefficient

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@ember kernel

ember kernel
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The quadruple 1 2 3 6 could work because you could create 2/1 and 6/3 with them, which are equal

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You're looking for equal fractions

quaint imp
#

yeah so wouldn't 2/4 wrk?

ember kernel
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2, 4 is a pair, not a quadruple

quaint imp
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okkk

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OHHH

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i get it

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so for example 2/4 and 6/12

ember kernel
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Yeah

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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

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(They'll be the same for y)

quaint imp
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y 3 numbers

ember kernel
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Because there are 3 powers of x involved in the equation

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You're looking for these powers so you need 3 values

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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

ember kernel
#

Any question ?

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While I'm still here

quaint imp
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yeah imma answer the question then if u r free u can see if correct

#

@ember kernel

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these r all the possible coefficients
i found

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1/2, 3/6
.
2/4, 4/8
.
1/2, 2/4

left knoll
#

@ember kernel if ur availiable sir could you please explain q10 b to me

ember kernel
#

Quadruples can be made from combining pairs

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Regarding x, you have all the triples : m, n, (m-n)
(same goes for the y's but with different values)

ember kernel
left knoll
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ty ty !!!!!!!

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sir you are a godsend

ember kernel
quaint imp
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damn thats ur choice...but i think u shud do them urself...but thats just my opinion

left knoll
#

bro ur not gonna learn anything lmao

tawdry dust
#

Sorry for disturbing, how to solve cosh x -3 sinh y = 0 and 2 sinh x + 6 cosh y = 5 ?

ember kernel
atomic dagger
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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 ?

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considering this is the answer:

supple island
atomic dagger
supple island
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matrix product is different from product between scalars

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two matrixes multiplied by each other can give 0 as a result even if one is not 0

atomic dagger
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yes, but i don't see how we found this result

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like what steps did we take, it's confusing me

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sorry if i'm being confusing

supple island
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can you do the product between a matrix and a vector?

atomic dagger
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yes

supple island
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ok so

atomic dagger
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when i put the multiplication into a system, i obtain: x = -14/5 z and y = 8/5 z

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and i don't know how we go from here

supple island
#

z can be whatever we want

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so we just say 5 for covenience

atomic dagger
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ohh okay then what about the "s" in front of the vector that's any real number ?

supple island
#

yes because whatever s is the result doesn't change since s is a scalar

atomic dagger
#

if z was a fixed number, and not any number we choose, "s" wouldn't exist right ?

supple island
#

no, s would still be there

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since s is a scalar, it's commutative for multiplication, so we can imagine we put it before the matrix

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and the product between the matrix and the vector is 0

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so no matter what s is

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if we multiply a scalar by 0, the result is always gonna be 0

atomic dagger
#

okayy i get it now!! thank you ^^' you always explain things really weel

supple island
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np

tardy tinsel
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Hello

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Can someone helpme solve the first one in q1 b)

sullen verge
# tardy tinsel

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

sullen verge
# tardy tinsel

la demi tangente est déjà representee sur le graphique dc ta juste a calculer sa pente

tardy tinsel
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Pour qu’elle soit la pente de la demi tangente il faut que f(4-x) soit f(x) non ?

sullen verge
#

oui mais ici ca revient au meme

tardy tinsel
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Comment je trouve f(x) à partir de f(4-x)

sullen verge
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puisque f(4-x)=f(4-2)=f(2)

sullen verge
tardy tinsel
#

Ahh j’ai compris

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Et la deuxième limite ?

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h—> 0+

sullen verge
#

honnêtement g tjrs pas trouver

tardy tinsel
#

Ahh merci en tout cas

sullen verge
#

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

sullen verge
sullen verge
tardy tinsel
#

Tous les exercices ?

sullen verge
#

merci beaucoup !

tardy tinsel
cinder yacht
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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

orchid orbit
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ah jm

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anh cambodia

hasty quartz
quaint imp
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guys i need help

shell comet
#

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

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Since there is only one source of income the total will be the same as the one income

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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?

wraith void
wraith void
glacial dust
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any physics or eng ppl that can help

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this was a lil bit spicy compared to the problems I solved already

left knoll
#

Where did I go wrong with my integral ( in the red) the answer is meant to be 25/3

wraith void
#

can anyone explain me strain on the rope? (ik it's physics)

left knoll
wraith void
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no like the definition

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I understood the other parts

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but the strain part I don't know

left knoll
#

ok hold on ill explain once i help the user with part d

wraith void
#

ok sure

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Making the angle lower will increase frictional force right?

left knoll
wraith void
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normal reaction is mgcosθ

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so the frictional force 375×2×(rt(3)/2) right?

wraith void
left knoll
#

no i figured it out

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forgot to change bounds in u sub

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so dumb lmao

wraith void
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No like I want to try

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that question

left knoll
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is a continuous probability question

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so application of integral

wraith void
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probability?

left knoll
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yep

wraith void
#

I didn't touch probability yet but I know a bit of integration

left knoll
#

i can send u some hard integrals lol

wraith void
#

Send one just for fun

Idk if I can solve it

left knoll
#

can u integrate trig functions

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ill just send on

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dm

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one sec though

wraith void
#

ah ok

left knoll
#

Easy one

glacial dust
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if a car would go up a hill frictional force increases as the angle of inclination also increases

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they are not inversely proportional to each other

wraith void
#

No
You know that a car slips when it goes on a steep incline right

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Also on a flat road friction is maximum

glacial dust
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oh yeah ur right

left knoll
#

im kidding its a confusing topic

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want me to explain again?

atomic dagger
#

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...?

solar ruin
atomic dagger
solar ruin
#

yes

atomic dagger
#

ah i see, i thought there might be a shortcut

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thank you!

quaint imp
wraith void
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Send that

quaint imp
#

ok

#

@wraith void

wraith void
#

variable expenses?

quaint imp
#

idk

wraith void
#

I mean it seems simple
Fill in the details

quaint imp
#

whats variable expenses

wraith void
#

Idk too

quaint imp
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wud that be like spotify

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since its like how much u use it?

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cuz its like a monthly subscription...the variable wud be a month

wraith void
#

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

glacial dust
#

would appreciate if someone could correct my work

wraith void
#

metal removed while machining one hole will be just the volume of one cylinder hole

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the total volume after machining 4 holes will be vol(cuboid)-4(vol(cylinder hole))

glacial dust
#

so for b it would only be the volume of the cylinder?

wraith void
#

yeah

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The metal which is removed

glacial dust
#

ok thanks

quaint imp
pseudo estuary
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for the 1st three years it is simple interest

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so use PxRXT/100

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and take that amount as the new principle for the next 5 years and apply the compound interest formula

quaint imp
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why devide by 100

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@pseudo estuary

pseudo estuary
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since r is a %age

quaint imp
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yeah ik

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so wouldn't it be 3000 x 4.5 x 3

pseudo estuary
#

also, add the original principle rate to the simple interest rate

pseudo estuary
#

per cent means divide by 100

quaint imp
#

ohh

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so it wud be 3000 x 4.5 x 3/100

pseudo estuary
#

add that to the new found prt/100 value

quaint imp
#

oh yeah ofc

pseudo estuary
quaint imp
#

so after i calcualte the interest i need to add the og 3000 with it

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ye got it

pseudo estuary
#

and that new amount is your input for the next 5 yrs of compound interst

quaint imp
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wuts the formula for compund interest

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WAIT

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ik

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@pseudo estuary

pseudo estuary
#

bruh

pseudo estuary
quaint imp
#

?

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dw ik it

pseudo estuary
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cool lmao

quaint imp
#

A = P(1 + \frac{r}{n})^{nt}

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that

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teacher told us

pseudo estuary
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so yes

quaint imp
#

lol

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wait but can u clarify that

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like cuz thats what the teacher gave us

pseudo estuary
#

that is p+( 1+r/n)^nt right

quaint imp
#

idk thats what the teacher gave us

pseudo estuary
#

yeah its 100% correct

#

dw

quaint imp
#

how wud u write it

pseudo estuary
#

that is your new "p"

quaint imp
#

yes

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this is the formula aunty google is giving me

pseudo estuary
#

yeah thats correct

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A will be your final answer

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p is yoour amount that u got after 3 yrs

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r is interest rate

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t is 5 yrs

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n is the number of times you apply the interest rate, in this case its 5 (cuz 5 yrs)

quaint imp
pseudo estuary
quaint imp
#

so its 8?

pseudo estuary
quaint imp
#

ohhhhhhhhhhh

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ok

#

i get it now

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k thanks

#

wait

pseudo estuary
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yeah right here

quaint imp
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but n and t are powers at the end

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what does that mean

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and since compund interest is also a percent wudnt we devide by 100

pseudo estuary
#

since it is compounded only 1 time in each year

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if they say "compounded half a year annually" or something like that you will have a diff n value

quaint imp
#

so

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for my case

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what wud the compund interest formula be

pseudo estuary
#

1 sec

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what is your p value?

quaint imp
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p?

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3000

pseudo stump
#

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

pseudo estuary
pseudo estuary
#

d/dx (x^n) is nx^n-1

pseudo estuary
#

here (a^x) is being differentiated WRT x

pseudo estuary
pseudo stump
#

i see

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did the 'a' suggest this or the equation?

pseudo estuary
#

i mean you are differentiating x wrt x in the first case

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albeit that "x" has a power/exponent

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in the 2nd case, "a" is differentiated with x, just that a has the power/exponent "x"

pseudo stump
#

i still see no difference

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i'll look some more online

pseudo estuary
#

sorry i couldnt help

pseudo stump
#

haha thanks for the attempt anyways, i bet that makes sense, just not for me (yet)

pseudo estuary
pseudo stump
#

ok nevermind

pseudo estuary
#

yeah i guess,

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constant raised to some power

pseudo estuary
left knoll
#

does anyone know continuous probability

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5 c pls

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where ami going wrong

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my work

floral jungle
fervent tide
wraith void
#

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

left knoll
fervent tide
#

should the answer be (c^2)/12 ?

scenic oyster
#

How I should do this equation? I can't use the calculator to resolve it.(teachers dont let use calculators on the exam)

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I already demonstrated that only have one real solution between 0 and 1

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I could use bolzano to make that interval even smaller, but I don't think that would be correct

left knoll
#

tysmmmmm

safe ember
safe ember
#

np, you're welcome

pseudo stump
wraith void
#

no problem

glacial dust
#

can anyone help me out 😀

supple island
glacial dust
#

yes

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b idk

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am not confident but yeah I can

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can u just walk me through

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then I'll solve it myself

wraith void
#

B seems easy right?

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it's just rt(2gh)

glacial dust
#

rt?

wraith void
#

root

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Square root

glacial dust
#

are u pertaining to the v^2=u^2+2as?

wraith void
#

yeah

glacial dust
#

cuz that will not work bcuz the hammer was not at rest

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its was being lifted

wraith void
#

It was not?

glacial dust
#

yep

wraith void
#

so what initial velocity was given

glacial dust
#

nothing

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thats why I need help xd

wraith void
#

then we can assume it's dropped right?

glacial dust
#

yes

wraith void
#

And what does dropping mean

glacial dust
#

free falling?

wraith void
#

yeah

glacial dust
#

potential to kinetic

wraith void
#

in free fall initial velocity is 0

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right?

glacial dust
#

uhm yes

wraith void
#

so u is 0
v²=2gh

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v=root(2gh)

glacial dust
#

ah ok then for a its just potential enrgy asking which is mgh?

wraith void
#

yeah

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mg(change in h) since they asked change in potential energy but anyways its 3.2m so m(9.8)(3.2)

glacial dust
#

yep ik that

wraith void
#

now m

glacial dust
#

but for c will I use momentum principle

wraith void
#

Is this question a continuation of the previous question you sent?

glacial dust
#

no it was the same

wraith void
#

ok

glacial dust
#

cuz I was struggling

wraith void
#

now we know velocity of hammer and pile since inelastic collision
and we know it goes 0.22m in the ground

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so find the retardation and multiply by the total mass to get the resistive force ig?

glacial dust
#

velocity of the pile was 0 right?

wraith void
#

after collison

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it's not 0

vocal dock
quaint imp
#

im so confused

pseudo estuary
#

b bruh

wraith void
#

bro

#

It's 7x+6

pseudo estuary
sullen verge
# vocal dock

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

wraith void
#

I thought we can use sinx/x

quaint imp
wraith void
#

np

sullen verge
vocal dock
wraith void
sullen verge
#

ohhh i dont think you can use that here since all of the variables are in the form of trigonometric functions

vocal dock
#

hopital too hard

wraith void
#

Yeah hopital is too long

vocal dock
#

L 'hospital

wraith void
#

what is it exactly anyways l hospital or hopital?

ember kernel
#

Example :

wraith void
#

No no

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I know the rule

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I was asking the spelling lol

ember kernel
#

Ohhh ok

wraith void
#

sorry to bother

ember kernel
#

It depends on your language

wraith void
#

well my sir uses both interchangeably

ember kernel
#

In some language they translated it by removing the s I think

wraith void
#

mhm

ember kernel
#

But the spelling doesn't matter, as long as you understand/are understood when speaking about maths

wraith void
#

Yeah

red spruce
#

tan theta = y2-y1/x2-x1

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answer is 2

quaint imp
#

anyone that can help me?

red spruce
quaint imp
#

its homework

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but since covid its online

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im just new to this

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like she didnt even explain

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can u explain?

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its cuz i skipped the questions i didnt understand

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and came back to them

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theres 25 quesions im done all except 3

red spruce
#

answer is 4 number

quaint imp
red spruce
#

yes

quaint imp
#

so the fourth option?

red spruce
#

ye

quaint imp
#

but can u explain how

red spruce
#

now go ready theory ill not answer more

quaint imp
fervent tide
#
  1. Assume x = a + bi and y = c + di
  2. Use the first equation to derive a formula for either x or y
  3. Combine the equations so you only have one unknown
  4. Then substitute that unknown with the expression from 0.
  5. Continue to find the other unknown
left knoll
#

idk if im allowed to help @quaint imp

wraith void
# quaint imp but can u explain how

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

somber reef
#

helpp~

left knoll
#

all of it? @somber reef

left knoll
#

Does anyone have any good calc 2 worksheets, specifically integration by substitution, and with answers.

#

like hard q

somber reef
wraith void
# somber reef

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]

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second part you can maybe do a=c/pq?

stoic zinc
#

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? 😦

solar ruin
# stoic zinc VECTORS A, B, C DIFFERENTS FROM ORIGIN ANGLE BETWEEN A and C = angle B and C, fi...

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)

main plume
#

i have a matrix determinant evaluation question can someone help me

left knoll
#

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

cosmic mountain
#

Anyone knows how to do this?

left knoll
#

@cosmic mountain

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You can simplify the denominators

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If anyone sees an arithmetic mistake please point it out though i think it should be fine.

#

can someone please help me with this?

left knoll
#

f(5)-f(1)

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I think

lofty arch
#

Yeah that’s right

floral jungle
#

Whoever needs a math help, come Dm me or ask here

cosmic mountain
arctic crater
#

hi there
can u help?

frosty flare
#

so <DAE= <ADE = 75
Angles in a quadrilateral = 360

#

360- 75-75=210

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<ABE+ <BCD = 210

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<ABE= <BCD therefore <ABE + <BCD = 2x

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therefore 2x= 210

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x= 105

#

i think thats right and i hope that makes sense : )

frosty flare
arctic crater
#

omg. 10q~~

frosty flare
#

np anytime

pseudo estuary
#

where is angle ADE?

ember kernel
pseudo estuary
#

but can you please explain how theyre equal? sry havent done math in a while

ember kernel
#

Symmetry

#

That's how you can tell they're equal

pseudo estuary
pseudo estuary
frosty flare
frosty flare
pseudo estuary
frosty flare
wraith void
#

is the theorem anywhere related to the two chords being parallel?
If so then the angle can be 105

pseudo estuary
pseudo estuary
#

so maybe thats it

wraith void
pseudo estuary
wraith void
#

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

wraith void
frosty flare
#

i mean

#

fair enough

pseudo estuary
wraith void
#

We join F and E

#

Cause we can

#

Wait

#

sorry

pseudo estuary
#

that still doesnt make fae

wraith void
#

FEA

pseudo estuary
#

yeah

wraith void
#

my bad sorry

pseudo estuary
#

yeah nvm

wraith void
#

Edited it

pseudo estuary
#

yeah, hopefully its less confusing to the OP now

#

lol

wraith void
#

lol

#

this is undergraduate level stuff?

pseudo estuary
#

lmao itso

#

idtso

wraith void
#

We learnt it in 9th grade

pseudo estuary
wraith void
#

yeah

pseudo estuary
#

if i were in 9th/10th, id be able to solve this easily.....i havent touched math in 2 years 😭😭

wraith void
#

I haven't touched this type of geometry in 2 years

#

we currently learning 2d and 3d coordinate geometry

exotic dust
#

does anyone know how to do transformations in alg 2?

#

i need help lol

cyan night
pulsar turret
#

Can someone help me find the volume of a cube with a surface area of 24a^2?

exotic dust
pseudo estuary
#

and the volume of a cube is = (side^3)

#

was that a joke question?

cyan night
exotic dust
#

Here i'll send a picture of the problem in a bit

atomic dagger
#

Anyone knows what this symbol means ?

ember kernel
ember kernel
pulsar turret
pulsar turret
pseudo estuary
pseudo estuary
pseudo estuary
outer pond
pseudo estuary
#

regardless, the answer becomes 8a^3 if the area is indeed 24a^2

pseudo estuary
# outer pond Yup

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

outer pond
left knoll
#

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

ember kernel
#

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

azure lion
#

help pls

left knoll
left knoll
#

why does P(Z<-a) = 1- P(Z≤a) explaining through symmetry of standard normal graph

ember kernel
left knoll
#

How do i do q 8 h

#

nvm im an idiot

proud portal
#

hey lads, can anyone help me with this

left knoll
# azure lion

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

left knoll
ember kernel
#

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

proud portal
left knoll
#

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

left knoll
#

does anyone know how to solve this?

clear fern
# left knoll 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

half coyote
#

guys, can anyone help me about solving that? I couldn't solve it

left knoll
#

x=5 y=6

clear fern
half coyote
left knoll
#

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

pseudo estuary
clear fern
#

lets say that (-x^2+31)^2 and we expand it
(-x^2+31)(-x^2+31).....

pseudo estuary
#

yep

half coyote
#

it becomes x^4 - 62x^2 + x + 961 = 41

clear fern
#

nope im tripping my bad

half coyote
#

there is 3 different degree xs, so I think there must be another technique. Solving with matrice maybe?

supple island
pseudo estuary
pseudo estuary
half coyote
pseudo estuary
#

i mean no 62x^2

supple island
clear fern
half coyote
supple island
#

how

#

it's y^2

pseudo estuary
#

MY BAD

half coyote
clear fern
#

a^2+2(a)(b)+b^2=(a+b)^2

clear fern
supple island
#

you are confused, you seem to say that (a-b)²=(a+b)(a-b)

#

which isn't true

clear fern
#

yea i just realised

#

thats when a^2-b^2

pseudo estuary
#

my bad

clear fern
pseudo estuary
#

sry my bad

clear fern
#

its fine amigo

half coyote
clear fern
#

oh well, cant help ya much

half coyote
#

thanks for effort

supple island
#

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

sullen verge
#

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

supple island
#

also M points of what

sullen verge
#

M(z) with z=x+iy

sullen verge
#

that doesnt seem right tho

supple island
#

you can start by saying |iz+2|=|z-1+i| so you have |ix-y+2|=|(x-1)+i(y+1)| , right?

sullen verge
#

can i do that? i mean the symbol "||" signifies a module

supple island
#

i mean you just divided by a scalar

#

3|z|=|3z|

sullen verge
#

ahhh right omg idk why i got confused

sullen verge
#

ull get x²+y²+4-4y = x²+1-2x+y²+1+2y

#

oh lol that's so simple

supple island
#

yep then try to isolate y

#

or x

sullen verge
#

thanks! got it. i just thought i couldn't simplify by 3

sullen verge
cinder yacht
#

<=> |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

sullen verge
#

ah non j'ai une question en fait

#

comment ta trouver la mediatrice si tu as le zi

cinder yacht
#

j'ai fail un truc

#

fixed

cinder yacht
#

|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]

sullen verge
#

ouii mais puisque z est multiplié par i, ca n'inverse pas laffixe des point ?

cinder yacht
#

my bad

#

un autre fail

#

fixed

#

comment ça ?

sullen verge
#

j'y comprend rien a cet exo 😭

cinder yacht
#

c'est quelle étape exactement que t'as pas compris

#

dans ce que j'ai fait

#

quelle ligne

sullen verge
#

pourquoi ta factoriser par 3i et pas par 3 ?

cinder yacht
#

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

sullen verge
#

ahhh

#

ok ok c bon

cinder yacht
#

la raison pour laquelle j'ai choisi |3i|, c'était d'avoir rien à côté du z de gauche

sullen verge
#

je pourrais te poser d'autres question sur le même exercice pour vérifié mes calculs ?

cinder yacht
#

oui ?

sullen verge
#

|-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

cinder yacht
#

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

sullen verge
cinder yacht
#

t'inquiète ^^

#

t'es français?

sullen verge
cinder yacht
#

j'ai des potes libanais avec moi dans mon école, ils ont fait prépa au liban

sullen verge
#

ah bon ? ils l'ont probablement faite là ou je pense moi même la faire

#

t'es en polytechnique ?

cinder yacht
#

oui comment t'as su

sullen verge
cinder yacht
#

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 :(

sullen verge
cinder yacht
#

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

sullen verge
#

tu as fais ta prepa ou ?

cinder yacht
#

sorry for the French spam

left knoll
#

Pls help

clear fern
#

how do you integrate question 6? Am I right to put u= In^3t? If yes, du/dx how do I differentiate that

left knoll
#

<@&717391911132069929>

supple island
# left knoll

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

ebon spire
#

Guys how is ln(an) converging to 2 here?

#

The power is n in the pic

supple island
ebon spire
#

I tried through 1 raised to infinity form but the question is asking me to specifically take l hospital after taking ln of an

weak mortar
#

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

clear fern
ebon spire
weak mortar
#

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)

weak mortar
#

and then i think you can use l'hopital right?

#

sorry for the confusion

tardy bone
#

derivative is the opposite of integral right?

ebon spire
azure lion
weak mortar
#

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

regal oxide
#

hello

left knoll
#

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?

left knoll
#

b) 4.62

#

c) 35.72

clear fern
#

hi i am not sure how do u integrate (sin 1/3x + cos4x)dx

atomic dagger
#

<@&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

worn mist
#

!purge user AbhiNoe#0857 50

ripe bayBOT
#

Member "AbhiNoe#0857" not found

worn mist
#

its only per channel aaaaaaaaaa

honest oxide
# clear fern how do you integrate question 6? Am I right to put u= In^3t? If yes, du/dx how d...

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).

honest oxide
# regal oxide hello

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.

glacial musk
#

Hi people

#

I need help with maths. function optimization. Can someone help me pls?

cinder yacht
#

oh ppl alrdy answered that

ember kernel
supple island
#

well yes, but A/infinty=0 and 0/A=0 with A a real number

#

so 0/infinity obviously=0

buoyant wedge
#

hey, would anyone be willing to help me with these 3 problems?

frozen onyx
#

Just need a hint on how to approach, please help

#

My solution:-

frozen onyx
#

Please help

left knoll
#

CAN ANYONE HELP ME

ember kernel
left knoll
#

Find the surface area of this

left knoll
ember kernel
left knoll
#

0.2 × (8+3x) = 0.4 × (3+2x)

idle bone
#

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

idle bone
weary arrow
left knoll
left knoll
#

Smh

ember kernel
#

Don't just "smh" her

left knoll
#

My bad but I always say smh but dont mean it so dont come at me [and everyone else -_-]

clear fern
valid idol
#

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 ?

dusty sequoia
#

does anyone know what epsilon and " | " mean in this pictures?

ember kernel
#

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

ember kernel
dusty sequoia
#

for the second screen, does the flipped A hold any special meaning?

ember kernel
#

Yep

#

It's the formal math symbol of "for all"

#

Wanna give it a try ?

dusty sequoia
atomic dagger
#

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

ember kernel
valid idol
#

hey quentin could you please look at my problem, if you know anything of that stuff 😇

left knoll
#

anyone? 😭

ember kernel
ember kernel
#

Oh yeah that one thanks

#

I saw it, but I've never been introduced to congruence I'm sorry

valid idol
#

no problem, thx anyways

left knoll
#

it’s maths but not maths 🙂

atomic dagger
#

<@&717391911132069929>

ember kernel
# left knoll would u somehow know mine?

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

supple island
left knoll
left knoll
ember kernel
supple island
#

oh ok

ember kernel
#

The rest of the division of a by b

atomic dagger
supple island
#

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)

supple island
#

<@&717391911132069929>

valid idol
supple island
dusk harbor
#

Knowing that p(1) = 2 and p'(1) = 1 and p(2) = -1 how do i write the polynomial on Newton's polynomial (Interpolation)?

dark sorrel
vast gyro
#

does anybody know any resources for vector calculus?

brave garnet
#

hi guys , need some help here, thanks

cunning forum
real zenith
#

hello

#

can anyone help me with statistics?

torn flower
#

Guys help me please

left knoll
#

<@&717391911132069929>

quaint imp
quaint imp
#

im so confused

glacial dust
#

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

supple island
#

whatever you like

glacial dust
#

nanometer squared sounds weird tho

supple island
#

wait, squared?

glacial dust
#

yeah cuz its area

supple island
#

so 10^-7 meters?

#

squared

glacial dust
#

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

supple island
#

sorry, it's 0,1mm²

glacial dust
#

SI units

supple island
#

yes

#

mm is millimeters

#

it's not nano nor micro

glacial dust
#

how do u know mm or cm tho?

#

its 10^-7

supple island
#

because in squared units 1m²=100dm²

#

so 10^-6m²=1mm²

glacial dust
#

oh so 10^-7 is the same as -6?

supple island
#

no?

#

10^-7m²=0,1mm²

glacial dust
#

then how do i convert this to 1.25x10^-7

#

how should I write it

supple island
#

multiply the right hand side too

glacial dust
#

but what happens if i multiplied it with 10^6

#

is it still considered as m2?

#

am getting 0.125

supple island
#

yes

glacial dust
#

oh ok thxx

willow basin
#

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.

left knoll
#

dy/dx= uv'-vu'

#

<@&717391911132069929>

willow basin
left knoll
left knoll
left knoll
ember kernel
#

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

left knoll
#

mb yea, thats def easier ^ and yea i was wrong, it should be y = x^4-x

tough elk
#

quick help why is it not 0

left knoll
#

(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

gritty cloud
#

Guys

#

How to prove triangle inequality?

ember kernel
dense fog
dense fog
dense fog
supple island
#

?

dense fog
dense fog
dense fog
dense fog
dense fog
pulsar turret
#

Can someone help me solve this question? Answer: (2,3) and (4,1)

dense fog
cyan night
#

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

left knoll
#

Hello can someone answer me the question why there is suddenly a -3? And not a -2?

left knoll
cyan night
#

yep

left knoll
#

Thank you

#

I seriously was like am I silly or the prof?

cyan night
#

😅

scenic slate
pulsar turret
#

Thank you!!

hoary bloom
left knoll
#

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

slow cobalt
#

this is parametrics

#

do you have to do anything before eiliminating t

#

can u make x = 90 and y = 7.5

left knoll
slow cobalt
#

man the numbers are not nice to solve it

#

ill try it

left knoll
slow cobalt
#

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

left knoll
#

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

slow cobalt
#

is the right side the working out for the asnwer

#

or is it part of the question

left knoll
#

No left side is the function and right side the answer

slow cobalt
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oh okay

left knoll
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I need an explanation

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I do not understand where the heck this 2/2 come from and then 1/6

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WTF?

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Yes pls

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But if you do 2/2*1/3

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It is 1/3

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How do you suddenly get 1/6

cyan night
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zanza r u middle school

left knoll
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Uhm

cyan night
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o okay thought ur role