math-help

[rocky moth]

I think this is right

[fickle swallow]

One of them but idk which one

[rocky moth]

@trail swift

sorry my answer is wrong 1^infinity is indeterminant form

ans should be e^-30

[fickle swallow]

Thnk youu so much

[candid rivet]

we need to use the fact that we're working on a LINEAR differential equation, which means that if you look at its homogeneous equation, then if y1 and y2 are solution then Ay1+By2 is also a solution (with A and B constant numbers). Hence here the right solution is the last one

[swift lake]

Hmm I understand that. But does the exponential e^t being different to y2(t) which is e^-t make a difference?

[candid rivet]

Oh you're right, didn't see it ! So yes you picked the right one, since it is in the form Ay1 with y1=a solution

[little hamlet]

hey guys im a lil confused by the markscheme here

why is the least possible value of n 4 and not 2

[exotic folio]

the function is increasing so for any number <4 f'(x) is below or zero

[vestal peak]

can someone solve the logarithmic equation 8log₂(0.6(x-3))-7

and post the solution please

its the only question i cant solve idk why

[dawn oxide]

what do i do for #29

bc after combining its sin(r^2) which idk how to integrate ngl 😭

if it was (sin(r))^2 itd be nice bc identity

[lavish copper]

james stewart book is alwas good

[amber inlet]

thanks bro :)

[cursive crest]

does anyone here know about Shortest Job Next (SJN) or Shortest Job First (SJR) for Preemptive method?

it's a lecture for Operating Systems, i'm confused on how it flows to the gantt chart

If anyone knows, I would gladly appreciate it 😭

[candid rivet]

is it =7 ?

[vestal peak]

answer says 8.06

[candid rivet]

no i meant the = sign of the equation. There is no = in your equation

8log₂(0.6(x-3))=7
log₂(0.6(x-3))=7/8
0.6(x-3)=2^(7/8)
x-3=[2^(7/8)]/0.6
x=3+[2^(7/8)]/0.6 ~ 6.06

I don't know if it is the right equation, but what you need to know is :

log₂(X)=b if and only if X=2^b

and it is still true if you replace 2 by every real positive number a>0

[dire aurora]

Super simple, but my answer is not the same as the textbooks answer - 6pi cm^2. is the textbook wrong? I keep getting half pi cm^2

[candid rivet]

area of a circle : pi×r²

40' =60' ×(2/3) which means the area is 2/3 of a full circle

Thus, area= pi×(3)² × (2/ 3) = 6.28

[dire aurora]

Oh i was working with the hour hand 😪

[weak lotus]

Does the equation between de brackets reminds you of something?

[dawn oxide]

nvm i got it now

[left knoll]

which one of these is the expresion above equal to

[earnest heron]

its 4 cos^2 (a-b/2)

If you'd like a proof ping me

[left knoll]

No thanks I now was able didn't know what answer to get to

[earnest heron]

👍

[glass matrix]

https://cdn.discordapp.com/attachments/1110877318852907069/1206167279226847232/image.png?ex=65db05d0&is=65c890d0&hm=617310d78376145d41230d7766b6dc407bcab11ed59a76ef1ba16a6515306f16&

please help 🙏 using mathematical induction btw!

[vague bramble]

Can somebody help with Normality Testing in statistics?

[candid rivet]

you can "notice" that each term is actually equal to 1/3[1/(3i-1) - 1/(3i+2)] =1/3[1/(3i-1) - 1/(3(i+1)-1)]. Thus you can factorize by 1/3 and then in the sum everything cancels out except the first and last term : S=1/3 sum with sum=1/(3-1) - 1/(3(n+1)-1) = 1/2 - 1/(3n+2) = (3n+2-2)/6n+4 =3n/(6n+4)

the "we notice that" part is called partial fractions

also if you want me to write it on paper so it's clearer i can

[glass matrix]

yes please!

[candid rivet]

there you go

if you want an other problem that uses the exact same techniques, you can try to prove this equality
Have a good day !

[candid rivet]

Ohh i just thought maybe they wanted you to do it by induction since they give you the result, tell me if that's what you're actually studying

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[opal oriole]

=tex 5x-8>2

[naive dew]

Wtf

[honest belfry]

Pleas help I’ve been stuck on this calc 2 question for an hour now

I just don’t understand how u can do this without the height of the cylinder

Question : “ A water storage tank has the shape of a cylinder with diameter 22ft. It is mounted so that the circular cross sections are vertical. If the depth of the water is 13ft, what percentage of the total capacity is being used (round to tenths place)

[wet flax]

existence of this limit, please

[left knoll]

how can i level up my mathematic solving skills?

[tribal lance]

If a 6 inch cube is filled to 3 inches then it is half full
in the question you posted you dont need the length of the cylinder at all

"It is mounted so that the circular cross sections are vertical" so the cylinder is not upright - che circles are at the ends - its like a tunnel
it has a diameter of 22 feet
if the water is filled up to 11 feet, the tank would be exactly half full

in the cube example, the relationship between the depth and the percentage is linear
but the cylinder acts differently
to get the first foot of water depth takes way way less water than getting the 11th foot because the tube is way thicker in the middle

you now need to figure out how much (percentage) of the total area of a circle with d=22ft is below 13ft

[tribal lance]

https://www.wolframalpha.com/input?i2d=true&i=Integrate[Sqrt[1-Power[x%2C2]]%2C{x%2C-1%2CDivide[2%2C11]}]

and divide that by the area of a semicircle

we only need to calculate for a semicircle because the water in the tank is perfectly symmetrical
you cant fill the left and right sides to different percentages

[candid rivet]

i don't think the limit exist.
Let's say x=1, then y->1- and then y->1+ makes the limit equal to +infinity and -infinity

but i might be wrong i haven't studied that yet

[surreal merlin]

A chopper 1200m above Yemen boundary towards Red Sea, observes two ships,
one is Cargo ship and the other one is Naval ship at angles of depression of 30° and
60° respectively.Based on the above given information, answer the following questions (assuming
line joining the ships leads to the point below the chopper):
i. Find how far is Naval ship from Yemen boundary.
ii. An anti-aircraft gun fixed on naval ship is aiming to hit the chopper. Find how far the
target is, from the gun.
iii. Find the distance between the ships.

[gilded tulip]

hey guys, did i get it correct? i think the last trace is a little weird

[surreal merlin]

can someone please tell the answer?

[frigid ingot]

In the first part, value for x and y should be +- underroot 2 and +- underroot 3 as by your values it would give 2 on LHS and 1 <as given> on RHS

[earnest heron]

i) 2078.46m
ii) 2400m
iii) 1455.64m

[surreal merlin]

Thankss

[ebon thorn]

guys if anyone is able to solve this

ill admit they r a math god

jus for ref this is a siingapore elementary grade question 💀💀

[frigid ingot]

Ur solution

[ebon thorn]

bro whats ur final answer i cant see

[frigid ingot]

53/3

[ebon thorn]

nah bro thats wrong

dm for explanation

[frigid ingot]

or 17.6 (approx)

[ebon thorn]

no

its not in decimals brother

[south gate]

Z=4 two whistles

[ebon thorn]

if anyone solves this correctly

i swear they are einstein

[frigid ingot]

oh wait.. sry i took the other sign to be + rather than X

mb

[ebon thorn]

dm for explanation tho i aint givin here

[south gate]

and the last answer is

20

[ebon thorn]

no sorry

lmao

dm for explanation

[frigid ingot]

it's 30

[ebon thorn]

no

[frigid ingot]

wtf

[ebon thorn]

bro theres this detail so insignificant

i cant tell u tho

[frigid ingot]

fine i'll try once more

[ebon thorn]

bet

[frigid ingot]

ok

[rocky moth]

yes it is 30

isnt this ez

[rocky moth]

abbly pemdas or bodmas in the end

apply*

[gilded tulip]

oh sorry i dont get what you mean

[frigid ingot]

umm.. actually i too thought the same but it isn't it

there something more

[frigid ingot]

Actually i too don't actually know much about that thing but I have just checked the first part and it seems that by subsituting ur values it's giving 2 on LHS and 1 on RHS

[rocky moth]

MAAN i even substituted my values

how am i wrong ?/ prove it if i am

[candid rivet]

the thing is that on the third line there are 2 times 2 whistles, whereas on the 4th line it is only 1 whistle

[rocky moth]

no i think it is one whistle + one whistle

isnt it

[ebon thorn]

no you both are wrong it isnt 30

its 16

@rocky moth @candid rivet

[frigid ingot]

Actually this question was given by @ebon thorn so I don't really wanna ruin his riddle... U can refer him for solution

[drowsy birch]

This is easy af, lemme check first 💀

[drowsy birch]

Here's the answer: 30 🫡

[rocky moth]

YEAH idk what is fuss abt

[rocky moth]

elucidate yourself

[left knoll]

Hello
Is there a quick way to solve this equation?
162.75÷ x =93

[candid rivet]

162.75/x=93 iff 162.75=93x iff x=162.75/93

(multiply by x on both side and then divide by 93 on both side)

[left knoll]

That's what I'm supposed to prove
I'm asking if there's a shorter way to do it

[ebon thorn]

@drowsy birch haha bro if it was that ez i wudnt give it and the answer is 16 dm for explanation lmao

[candid rivet]

Not really a shorter way but it will always work with this method :

1. Use the euclidian division (x/y =(ay+r)/y = a+r/y with r<y
2. write r and y as products of prime numbers so you can simplify the expression

[cloud vapor]

my first doubt -= Why Circle Is CONSIDERED OF 360 degree ?????

[rocky moth]

why not it is a simple number thats why

[grave pollen]

FRЕЕ GIFТ DISСОRD NIТRO - discord.com/freenitro

GET FREE FORZA HORIZON 5 - discord.com/freenitro

[rocky moth]

<@&942391219206647828>

[frigid ingot]

Because a year is of 365 days but yet 360 because it is closed to 365 and is divisible by 24 numbers

It made the calculations and division of circle much easier

[gilded tulip]

hmm oh i think ure talking abt a diff chapter ? i may be wrong but im doing sketching

[vagrant gale]

One message removed from a suspended account.

[lethal slate]

What’s the solution ?

[left knoll]

Thank you

[sharp grove]

hi can someone help

[eager granite]

just letting u know, that's waste of page space, try splitting it into 2 halves

[terse turtle]

FRЕЕ GIFТ DISСОRD NIТRO - discord.com/freenitro

FRЕЕ GIFТ DISСОRD NIТRO - discord.com/freenitro

[drowsy birch]

🫡

[ebon thorn]

wrong lmao dm for exmplanation

[ebon thorn]

16

[lethal slate]

Post it here

[ebon thorn]

Let p = pink shoe, h = human, and w = whistle.
3p = 30 --> p = 10
10 + 2(h+w) = 20 ---> (h+w) = 5 (notice the whistle on the dudes jacket)
5 + 2w + 2w = 13 ----> w = 2

10 + 3*2 = 16 (Notice the final guy has no whistle on his jacket, so h = 5-w = 3)

lmao it all about visual observation ykwim

[lethal slate]

… 🤷‍♂️

[rugged crown]

its should be 1/2

how do you calculate it

-1/2

pweaase

[candid rivet]

ohhh the whistle on the jacket ok haha

[ebon thorn]

real

[lethal slate]

Where do I find these questions

[rugged crown]

the voices will whisper them

y?

know how to solve it

its a geometric progression with the ration

e^(1/n^2)

if u use the usm formula for that

its useless

[lethal slate]

What

[rugged crown]

why ?

[rugged crown]

.

[lethal slate]

I’m asking where do you find questions like this

[rugged crown]

@lethal slate

where u from

they are in my language

they are to apply to college

'u get a test with question simillar

[lethal slate]

Saudi Arabia

[rugged crown]

i need solution

[candid rivet]

ok i got it but i use the taylor expansion of exp and 1/(1+x)

[rugged crown]

idk it

can you write

a full solve

[rugged crown]

?

[rugged crown]

idk what any of that means

[candid rivet]

well i can write it if you want but if you don't know what taylor expansions are it won't make sense (basically it's a way of writing some functions as a polynimial + something that is to a certain extent negligible)

[rugged crown]

@candid rivet write pls

[candid rivet]

it's this

but maybe there is an easier way if you haven't studied this yet

[rugged crown]

i kinda understood

u aplied the sum formula

then

idk

ill look l8ter thx anyway

[rugged crown]

question tho

if the ratio

is under 1

then the sum formula switches to what you wrote

like 1- the thing instead of the thing -1

?

[candid rivet]

if you're talking about the geometric sum (sum of a^k for k=0 to n-1) then the formula is (1-a^n)/(1-a) = (a^n-1)/(a-1) no matter the value of the ratio (sorry if i did not understand what you said)

[rugged crown]

bruh u annoying af

how tf u know all of them

albert einstein im malding what grade u in or wtf

[candid rivet]

sorry i'm too late but i have the solution for your last post

[torn trellis]

😭

[candid rivet]

actually the method is the same

[torn trellis]

im so sorry @candid rivet that was wrong question

😭

[torn trellis]

this one is right question

[candid rivet]

use partial fractions and then try to make the maximum of terms cancel out each other

well tell me if you want me to do it or if the method is enough

[torn trellis]

can u do this one

ill really appreciate it

T-T

[rugged crown]

its the same

bro from now give the values 0 , -1 , 1 , 2

to figure out a b c d

than write it so it simplifies in the sum

[candid rivet]

haha thx ! I don't know what "grades" are (like to what level it matches) (I'm french) but I finished high school 2 years ago

[torn trellis]

wow u finished hs 2 years ago and ur still below 17yo T-T

[rugged crown]

that makes sense

what u below 17

[torn trellis]

ikr

[candid rivet]

wait no i'm 19 😂

[rugged crown]

aha ok

[torn trellis]

😭 ohhhhhh

[rugged crown]

better

[candid rivet]

why would i be below 17 ? haha

[torn trellis]

ur profile

[candid rivet]

oh because of the green ?

[torn trellis]

thisss lol ig u forgot to update it

[rugged crown]

so its like this

[candid rivet]

where is it to change ?

[torn trellis]

ohhhhhhhhh

[rugged crown]

if i didnt mess smth up

[torn trellis]

in roles

[torn trellis]

hmmmmm

[rugged crown]

ok now

@candid rivet

question

on this exercise if im wrong i think

if you split it out like this

and make it a sum of this

the first () will cancel out

but the second one wont unless i got c d wrong

and one should be positive

ye

c = +1/2

fuck

[torn trellis]

😭

[rugged crown]

this

from this

so now

the first sum in the paranthesis will be 1/1-1/2+1/2-1/3 ....

so it cancels out

the same in the second one

so it will remain 1/1 -1/10

if you said ti goes to then

same on the second one

same logic i mean

[candid rivet]

@torn trellis

[torn trellis]

ya??

im here

[candid rivet]

well i get this

[rugged crown]

yeah same as me

[torn trellis]

ohhhhhhhhh

thats how u gonna distribute the denominator

[rugged crown]

@candid rivet can u help with a exercise

whats b

so that the function is surjective

[torn trellis]

thankyou so much guys for ur help!

[candid rivet]

thats weird i dont see anything to change my age in roles

[candid rivet]

sorry two seconds i'll give a look right after

[rugged crown]

no worries

[torn trellis]

lol thats fine XD

[torn trellis]

yaaaa thats right

[rugged crown]

yeah

[torn trellis]

wait why u picked green color

[candid rivet]

yes harder if c=-1/2 haha

[torn trellis]

u should pick blue right?

[candid rivet]

oh shit i'm so bad 😂😂

[vagrant gale]

One message removed from a suspended account.

[torn trellis]

🤣 happens when ur only good at maths

[rugged crown]

how tf do u find the range

i tried the first derivative

and it isnt close to any answers

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[rugged crown]

equal the first derivative or the f(x)

[vagrant gale]

One message removed from a suspended account.

[candid rivet]

you're welcome don't hesitate if you need help 🙂

[torn trellis]

thankyouuu!!

[rugged crown]

like this

?

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

One message removed from a suspended account.

One message removed from a suspended account.

[rugged crown]

why is it greater or equal to 0?

[vagrant gale]

One message removed from a suspended account.

[rugged crown]

why

why does it need to have solutions

?

[torn trellis]

@rugged crown do u have the solution of that question in one slide ???

[rugged crown]

no i

deleted it sorry

[torn trellis]

nvm thats fine

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[rugged crown]

what grade u in ?

[torn trellis]

😭 it was taught in 11th grade right?

[rugged crown]

like why is it surjective if '

it has solutions

[candid rivet]

that's what i'm trying to figure out 😂

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[rugged crown]

surjective

if for every y there is a x

so if it has solutions

that means there exists a x

for every y ?

[candid rivet]

yeah you're right

so you're looking for the y such as the equation f=y has solutions alright my bad

[rugged crown]

still

either im messing up the numbers

cause im working in paint

or im f ing smth up

wait i redo 1 more time

if not i request help

@candid rivet btw f me ur too msart

actually im jealous

[candid rivet]

ok i'll give it a try

[rugged crown]

@vagrant gale u 2

[candid rivet]

no i swear i'm really not smart

[torn trellis]

@candid rivet how much maths u studied?

[rugged crown]

both of you f u

[torn trellis]

how many hrs?

[torn trellis]

ur

[candid rivet]

actually i'm kind of failling my tests right now 😂😭

[vagrant gale]

One message removed from a suspended account.

[torn trellis]

what books u followed? @candid rivet in hs

[vagrant gale]

One message removed from a suspended account.

[rugged crown]

ok

ggz

@vagrant gale thx

it s b

[candid rivet]

i get D=-3y²+15y+1

[rugged crown]

+18 y

fix it

right now

[candid rivet]

oh might be wrong then ouch

[rugged crown]

:>

[torn trellis]

@rugged crown what grade r u in?

[rugged crown]

im in 12

just turned 18

[torn trellis]

ohh

[candid rivet]

i was in a good high school so didn't really need to learn more out of schools

oh yeah 18y i have the same

[torn trellis]

ohhhhhhhh

[candid rivet]

guess it is the same for everyone 😭

but actually there are some decent videos on youtube

or some good websites

[rugged crown]

Ori aderall

Then every book is good

[candid rivet]

but i think what worked for me was to spend a lot of time practicing calculation, and then learning new stuff with because once you know how to calculate good I swear a lot of things become easier

[torn trellis]

wooooooooooohhh i swear i will study as much as i can to be good at maths

thnxxx

[candid rivet]

and then try to understand and learn the methods and why it works, more than learning things by heart (even if you need to know some formulas haha)

[candid rivet]

good luck then ! (:

[torn trellis]

ohh

[frigid ingot]

I found this online... actually i've done it but the method was pretty informal so i was looking for some better way to solve this problem

[mild monolith]

You didn’t write steps.

[topaz echo]

guys how do I factorise 4xsquared - 4x + 17 using the complete the square method?

[mild monolith]

We need to identify a complete square in this expression. (a^2 - 2ab + b^2)
Let’s start with a^2 it’s 4x^2 (because they have the same degree: 2)
So a is sqrt(4x^2) = 2x
Let’s look at the next term: -2ab, we know a, so b is equal to 1.
We know a and b, so let’s identify the complete square:
4x^2 - 4x + 17 = [(2x)^2 - 2 * (2x) *(1) + 1] + 16 = (2x - 1)^2 + 16

[topaz echo]

thank you

[candid rivet]

if you really want to be formal you have to check if x is such that the function is well-defined (square root of only positive numbers)

[rugged crown]

@candid rivet

can you calculate the limit of nIn

in this exercse please

i cant seem to do it

[candid rivet]

I have this

[candid rivet]

I do an integration by part and the last integral converges to 0

tell me if I'm wrong

but i know a lot of times when you have a sequence of integrals one of the trick is to do and integration by part, trying to create a relation between I_n and I_(n+1) for instance

and also find inequalities to calculate limits often

[rugged crown]

umm

usually when we do these ones

we do something related to I n+1 +I n

and we see that its a decreasing fucntion

or however you call it so we say

then that I n+1 + In < 2In

and we find out what In+1 + In equals

then amp

liek this would be the tehnique

but u cant do that since u have that annoy thing under the fraction forgot the name

[rugged crown]

yes this one is right

so u are in 0 x infinity

and u cant to shhh abt it

[rugged crown]

and idk what u did here

honeslty

integration by parts ?

[candid rivet]

I integrate the x^n and differentiate the 1/(x^2+4x+6) in my inetgration by parts

[candid rivet]

i don't understand what •|• n/2 means

[rugged crown]

lol

miss click

just multiply by n/2

then u apply a limit both sides

so that the yare equal to the same thing

so if its greater and less than smth its that smth

[spice solstice]

solve for a,b,c
a+b+c=0
5a++4b+3c=3
6a+3b+2c=-1

also explain please

[candid rivet]

1. Express a with b and c
2. Write 2 expressions that only involves b and c
3. Combinate these two expressions such that either b or c disappear

[candid rivet]

damn that's smart

[spice solstice]

thank you very much man that helped a lot

was stuck on this annoying question

[rugged crown]

u can do cramer

and

write it as a matrix

less calculations

[candid rivet]

yes but with cramer you still have to calculate 3 determinants of 3x3 matrixes. Wouldn't use cramer even if it works

[rugged crown]

@candid rivet
yo

i did the exercise

same answer as you

gj

this is the fancy way lets say

[potent radish]

The doubt is I don't think going from dy/dx to dx/dy is valid cause dy/dx is not a fraction.....so the above soln is correct or not?

Below*

[candid rivet]

okkk really nice to calculate I_(n+2) + 4I_(n+1) + 6I_n
nice trick ! (:

[candid rivet]

from what I've seen on internet yes that works
https://youtu.be/62EcIqPMW4s?si=E_VFkzMrWo-WaM6U

[potent radish]

Oh okayy
Got it
Thnxx

[rugged crown]

u really have to explain ur solve

i cant get it no matter what fr fr

where did -1 go

?

why not -10/11

[candid rivet]

it is -1 times 0

the last big integrals equals 0 when n-> +infinity since I_n -> 0

and integration by parts is actually just :
[fg]' = f'g + fg'
f'g = [fg]' - fg'
and then integrate the last line (knowing that integral of [fg]' is just fg)

[thick parcel]

does anyone know how to solve this?

[left knoll]

can someone help me with statistics? It's about discrete distributions (probability)

[thick pine]

I probably can but my english is not quite good enough to understand the conditions

[thick pine]

I'd start by completing the square

[thick pine]

Maybe, just ask and if I can I will help you

[left knoll]

During a long holiday weekend, an average of 2 fatal traffic accidents per hour is recorded (assume that these traffic accidents occur independently of each other).

a) Calculate the probability that an hour can pass without fatal traffic accidents.
b) Calculate the probability that 15 minutes can pass without fatal traffic accidents.

We need to use Poisson, the answers i got are

a) 13,53% chance that an hour can pass without a fatal traffic accident.
b) 60,65% chance that 15 minutes can pass withotu a fatal traffic accident.

[thick pine]

Bruuhhh no latex

[thick pine]

b) is harder: 2 accidents per hour = 1 per 30 minutes = 0.5 per 15 minutes, so µ=0.5, x=0, then we get e^(-0.5) = 0.6065

Hope that helps 🙂

[left knoll]

how would u find X?

I know all the angles

32, 90 and 58

but I only have one of the variables for pythagorus which is the hypotenuse. Can someone pls help me out? thx!

[left knoll]

You can use the sine rule

[thick pine]

Law of sines

The math bot is useless

[left knoll]

Could you explain the sine rule? we haven't done trig in a while

[thick pine]

In your case, you know gamma = 90° and c = 15cm and can use that to calculate the length of a and b since you know the angles alpha and beta

[left knoll]

Basically sin(x) divided by the side opposite it has the same value as any other angle (like sin(y) or smth) over their own opposite sides

Kinda hard to put into words, this might explain it better

And the equation above my messages

we havent gotten to that part in class yet so that prob explains why idk, thanks a bunch!

I got another question thats got me confused a little:
I'm guessing c is 11 because thats where P is ?

[thick pine]

The question is: Why is P at (0, 11)?

You know P is at (0, c), but how do you conclude that c must be 11?

[left knoll]

I conclude its 11 because of the diagram

but is that the only way? is there no way via calculation?

[thick pine]

So you've read the value/measured the distance?

[left knoll]

I think its 11 as this is what I see, but I may be wrong, I frequently am so I'd like to see what u think

[thick pine]

Ah, but you can't be sure, it could be 11.1 or 10.9 or anything in between

[left knoll]

Your right, how would you get 11 then?

[thick pine]

There is! We know that the Point is on our parabola! Can you find a way to use that in the equation for the parabola we've got?

[left knoll]

would you factorize the equation?

[thick pine]

So far (if you've done question a) you have y = (x - 3)² + 2

[left knoll]

Yup

That's what I've got

[thick pine]

Now you know that

1. the point P is on your parabola so if you put in its x and y values the equation must match (like 1=1 or 2=2)
2. you know P's x-coordinate is 0

How does that help you?

Ok do you want me to tell you?

[left knoll]

I was going to say u subsitute the x coordinate 0 in the brackets

so it becomes (0 - 3)² + 2

[thick pine]

Well done!

[left knoll]

and for a minute I thought I was asking a silly question 😅

so now that its 0 how will that give me 11? would I factorize the double brackets?

[thick pine]

Uhh what do you mean?

You put the x=0 in the equation which gives you (0-3)²+2 = (-3)²+2 = 9+2 = 11, that's the y-coordinate

[left knoll]

I think I got it

yeah

👍

appreciate the help

[left knoll]

How come a = -3? Is it because the coordinates given correspond to a turning point = no change?

and B is 2 because thats what is substitued for b ?

[thick pine]

b can be read from the point (idk how it's called in english, the deepest point of the parabola)

b is its y-coordinate, a is its x-coordinate negated

[left knoll]

ah mk

[thick pine]

Ah apex is the word i was looking for i think

[left knoll]

you see this? is this the same as -25 over 4?

[thick pine]

yes it is

[left knoll]

👍

[thick pine]

and also the same as 25 / (-4)

[left knoll]

see for this one? I got 3 without the bracket

is that because I multiplied first?

Yeah

I'm supposed to add r first?

Yup

👍

But if you decide to multiply by 3 first you should multiply everything, so that would mean that the equation turns into the following:

3P = mn - 3r

But it's better to move r first

I multiplied first and ended up with 3p + r over n

and that is wrong right? cuz its different from the 3 outside of the bracket

Yeah 3p + r over n is wrong

Try to like isolate the variable you want to make subject

👍

would I use the quadratic formula for this?

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[left knoll]

So my answers were correct right? Only difference between yours and my answers were that i expressed mine in percentages? Or is that forbidden to do?

[thick pine]

Ah I thought they were solutions

I can't guarantee the correctness of my answers 😆

[frigid ingot]

Your needed solution is before the solution of Quadratic equation but this topic is also gonna be there in exams so I solved it...

And since there it is not mentioned to solve the quadratic you don't need to apply quadratic formula

[rugged crown]

@candid rivet bro help

its just says caulculate

[rugged crown]

im sorry

i solved it and deleted it

but i have 1 more

[candid rivet]

oh okay haha

[candid rivet]

If A is the value, we see that A^3+3A-14=0 which only has one real root

no probleme

[rugged crown]

u could write

it

as

1+rad 2 ^ 3

(1+rad 2)^3

[candid rivet]

oh nice

[rugged crown]

ahaa

i also got that solution

but it was ugly af

cause u had 2 more

[candid rivet]

i thought about it at the beggining but I thought there were gonna be some weird x^(2/3) which is totally false

[rugged crown]

ye

[thick pine]

Can anyone tell me an example for a ring with an irreducible element which is not prime?

[forest aurora]

R=Z[sqrt(−5)] - element 2

[left knoll]

could somone please explain this to me?

[storm hawk]

Which one

[left knoll]

both please

[tame topaz]

Part (a) is using baseheightdepth= volume and you sub in the given values. Part (b) is solving the quadratic that you get from part (a)

[storm hawk]

B its the quadratic formula

[bold atlas]

welp

[left knoll]

can someone please help me out with c? it says the answer is supposed to be 23.2ft but I ended up with 24.3ft

[tropic isle]

This is an inhomogeneous differential equation you have to solve. The solution is f(x) = exp(-3x) + 1. To get the final answer you just have to plug in the asked value for f(x).

@bold atlas

[tropic isle]

Please send your calculations

[tropic isle]

I get 23.24ft wit the help of the law of sines

@left knoll

[tropic isle]

The mistake in your calculation is that when you put the pole back into position, the angle is not 65 degrees.

[left knoll]

I want to start off by thanking you for taking your time to help me out, could u explain to me what to do instead of using 65 degrees?

I used 65 degrees as I thought I cannot calculate anything even with the sine rule if I have more than 1 unknown variable

[tropic isle]

Look at my solution above. When the pole is skew, I calculate with the sine rule the distance between point F and G. Because when you flip the pole to the right position, the distance between F and G remains the same. Finally I just use pythagoras to calulate the length of the wire. The problem of your calculation is when you would just imagine to rotate the skew pole so that it is normal again, you would also make the angle which was 65 degrees bigger.

Hope that makes it clear

[tropic isle]

Thats what i mean with the rotation to the normal position

Look how on the right the angle gets bigger

that's the reason why you can't use the 65 degrees anymore

[left knoll]

so ur left with 90 degrees

and 22 feet

interestin, ill take a more detailed look at this tmr as I'm really tired and just finishing up with some English work now, Thank you very much Maciel!

[desert barn]

does anyone know how to test h(t) for causality in an LTI system?

[tropic isle]

Yes, you have to calculate the impulse response and check if it is zero for t < 0.

[desert barn]

for h(t)=e^2t u(-1-t) it would be non causal ?

[formal burrow]

I never done this type of math be4

[tropic isle]

Yes

[formal burrow]

Math question here

If y is 3 and x is negative 4 how do I graph that in a graphing call

[thick pine]

in your coordinate system go 3 up and 4 left

[formal burrow]

Thanks

[desert barn]

can someone explain where the tau+1/2 came from?

[tropic isle]

whoever evaluated this integral left some steps in between the solution. I'm not sure but i think you can solve this integral by "integration by parts". But you could also just check if it is right by taking the derivative of the solution.

[past thunder]

I am having trouble with hyperbolic functions

Is there a geometric interpretation of hyperbolic like regular sin/cos ?

[thick pine]

https://en.wikipedia.org/wiki/Hyperbola there are a lot of graphic examples

[left knoll]

Would I use the sine rule for this?

[left knoll]

side 1/sin(angle 1) = side 2/sin(angle 2)

Replace then by the values including the variable e

Then rearrange to find e itself

[left knoll]

You see for this what did u get for the angle on the top and on the bottom right?

[bold atlas]

whats the limit x tends to negative infinity for? i dont get it, i do solve the diffferential equation but dont understand the limit part of it

[forest aurora]

@frail dust scammer

the actual link on that hyperlink is https://u.to/wgBmIA

@trail swift ban

pls

🙏 🗣️ 🔥 🐟

[trail swift]

thank you, they are banned

[undone ledge]

can i please get some help for this question

[undone ledge]

and question 24.....

[lilac vigil]

anyone know how to find the derivative of this? (using high school level calculus)

[thick pine]

apply the chain rule multiple times, also product rule once
y = a(b(c(x))) * a(b(c(x))), where a(x) = cos(x), b(x) = sqrt(x), c(x) = (2x+1)^2 - 1

[left knoll]

you need permission for this
!warn @vestal charm

tagging everyone?
!warn @vestal charm

[proper venture]

Hello

Can anyone share IB grade 7 Algebra questions? Like practice for summative. It will be helpful.

[tropic isle]

That's just a boundary condition to determine the unknown constansts

[left knoll]

how would one do this?

[left knoll]

I also don't understand this

[tropic isle]

x length of pyramid is 2x(5-2) = 6, y length is 2x(2-0) = 4. Therefore B is at (8,4,0). For b) just determine the length of A to the middle by using pythagoras. After that you can again calculate the length AV with pythagoras

[tropic isle]

I'm not sure but if the lines go through the center of the circle, y should also be 120 deg.

[left knoll]

Y=120° due to the fact that opposite angles are equal

[left knoll]

I got the wrong answer for this how would u do it?

[left knoll]

does this always apply?

[left knoll]

could you elaborate please? I'm sorry but so far I don't get it

[left knoll]

I think so

[tropic isle]

which part in particular you don't understand?

[left knoll]

to be frank, most of it

[grizzled dust]

can someone explain why this is the answer

i tried it again and i got e^-2x/-2

[frigid ingot]

Yeah... in any case if two lines intersect each other, then both pairs of opposite angles will be equal

[thick herald]

The correct answer is [e^(-2x)/(-2)] + 3x² tho..

[grizzled dust]

idfk know bro

[vagrant gale]

One message removed from a suspended account.

[candid rivet]

@grizzled dust

[plucky sail]

thats the same thing as saying -1/2e^2x

[left knoll]

could someone explain how to do this pls? thank you.

[still sedge]

I think this is the solution

[left knoll]

That is the solution, could you walk me through the pythagorus part? why is it subtract? is it because you already have the hypotenuse?

[still sedge]

The hypotenuse of the triangle is the radius of the circle

Here CB=QC=PC= radius of circle

[left knoll]

so thats why you did subtract right?

[still sedge]

Yes 😀

[left knoll]

I kinda get it, this is what I see so far

so u got 12cm which is A and A is the two triangles

15 is the hypotenuse of both triangles

so to get AC you just do pythagorus

[still sedge]

Yes AC=12 cm

To get AC you subtract CB=15cm from AB=27cm

Then you apply pythagoras to get AQ

[left knoll]

so is this what ur doin?

[still sedge]

Yes

[left knoll]

and you got AQ after doing pythagoras

then you added AQ and AP to get PQ, am I understandin this correctly so far?

[still sedge]

Yes

AP=AQ as A is the midpoint of PQ

[left knoll]

ahhhh I gotchu

and thats it ?

[still sedge]

Yesss

[left knoll]

thank you a million, very helpful 😄

[still sedge]

You are welcome, glad to help you.

[left knoll]

How do we get this 8000/3? this doesn't make sense to me...

this is the question

[candid rivet]

What step don't you understand ? I think the calculation of the integral is right

[candid rivet]

Tell me if I made a mistake i'm bad at probabilities.

The only things I used are :
P(Ā)=1-P(A) where Ā is the contrary of A
P(M∩N)=P(M)+P(N)-P(M∪N)
P(M∪N)=P(M)+P(N)-P(M∩N)
A∪Ā is a certain event (its probability is equal to 1)

And formulas like :
(A∩B)∪C = (A∪C)∩(B∪C)
(A∪B)∩C = (A∩C)∪(B∩C)
Ā∪Ē = contrary of (A∩E)
Ā∩Ē = contrary of (A∪E)

[torn trellis]

😲 OMGGGGGG

ITS RIGHT

THANKYOU SO MUCH

[candid rivet]

haha you're welcome ! (:

[haughty belfry]

Does anyone know how these formulas or are derived？

[torn trellis]

T-T

[violet rampart]

<@&942391219206647828> Idk if this is alright to do ?

[wind crane]

Does anyone know a video that explains how to solve this?

Or can someone explain to me how to solve this?

[left knoll]

I can't solve the integral...

[bold dagger]

i need help

[candid rivet]

Tell me if there's something you don't understand

[left knoll]

YOOOOOO I DIDNT KNOW THAT FIRST FORMULA!!! thanks man

[dusk crater]

can anyone help me with this

[tropic isle]

https://en.wikipedia.org/wiki/Separable_partial_differential_equation

i did not look at your problem but maybe this will help you

[wheat spindle]

Adobe Full Espanol GRATiS 2024
https://telegra.ph/Adobe-GRATIS-2024-FULL-ESPANOL-02-25
Tutorial video
https://www.youtube.com/watch?v=0vNlpHfAttU
@everyone

[dusk crater]

thanks for your help,but i have a whole book to read about that,the things is i dont understand how its work,anyway i solved it myself,hehe

[left knoll]

Get free gift 50$ - steamcommunity.com/gift/50

[left knoll]

https://www.youtube.com/shorts/PRevO1QdzKY

[gentle trellis]

answer is d

[somber berry]

which calculator would you recommend between the texas instrument 83 and 84? is there really a difference?

[severe cosmos]

get the 84, for one, its the standard for most math classes

it also has a lot of processing power for when you start graphing more complicated functions, and has mathprint so fractions can be written in actual fraction form instead of 1/2 or 0.5

also a bigger screen iirc

plus if theres any firmware issues, theres a port

[left knoll]

anyone know what formula I would use for this?

[lethal slate]

42

[candid rivet]

You can use the sine rule
a/sin(A) = b/sin(B) = c/sin(C)

Thus, sin(120)/62 = sin(BCG)/20
BCG = arcsin(20sin(120)/62)

GBC = 180 - 120 - BCG = 60 - arcsin(20sin(120)/62)

[plucky sail]

why this server flooding with bots 😭

[tacit pollen]

can anyone tell if this looks right? (for Calc)

[rugged current]

what is the notation name for the following?
XE(1;15)
and
2<x<-2 ; XER

[tropic isle]

x element of Real numbers between -2 and 2

x element of 1-15

[rugged current]

isnt there a specific notation name?

like for example interval notation

[weak lotus]

cosine or sine rule ma guy

[weak lotus]

lemme help

you forgot a cosine at the end

let me clarify:

3.cos^2(x), when defirentiating using the chainrule, we get:

3 in the front, since this is a constant, we are left with cos^2(x)
2 to the front power rule
we are left with cos(x)
so:
3 . 2. Cos(x) but the chain rule tells us we still need a derivative of the function f(x) itself, which in this case is cos(x)
taking the derivative, we get: (-sin(x))

resulting in:
-6cos(x)sin(x)

[weak lotus]

first one:

X is an element of the open interval ragning from 1 to 15, where X can not be equal to x and 15

Second one:

we need to find a number x, which values layes between -2 and 2, where as X is an element of all real number, and can not be equal to -2 and 2

[rugged current]

yea i mean thats like 8th grade math, our teacher asked us to name the notation being used or we have to go run laps on the field

[frigid ingot]

@trail swift Please look out for these bots

[charred osprey]

How would I solve #7? I know I have to find the momentum’s in the x and y direction, and then relate them somehow and then solve for final velocity, but how do I relate the two problems together?

[remote saffron]

In every type of collision you can use momentum conservation.
As you have already written that those balls have momentum 3mv î + 4 mv ĵ so using vector addition the resultant vector will be 5mv (in the shown direction)
So the momentum of two ball system is 5mv and total mass of the system is 3m, then the speed = (5mv)÷(3m) = (5/3)v.

[solar crane]

i'm getting recommended to study math, mostly becouse of my interest in epistemologi, more specifically rationalism, in use, i suppse. And therefore wonder if you guys know any good math lore youtube videos or channels? To, hopefully peak into, if a degree is a more practical vision is a solid choice?

[timid wasp]

Two small silly balls of super sticky silly putty

[lethal slate]

This server has the most useless mods 💀

[left knoll]

😭

@minor iris please do something 😭😭

[left knoll]

I'm struggling real badly with this, could someone explain it to me?

[limpid raft]

Hey, can somebody help me solve this?

[proven whale]

X=-2?

My maths is weak so sorry if I am wrong

[limpid raft]

Could you explain how did you solve it?

It is the right answer

[proven whale]

Is it correct?

[limpid raft]

ye

[proven whale]

I Hope it was helpful

[limpid raft]

It was, thanks 🙂

[proven whale]

Welcome 😊

[foggy torrent]

*find the number of the roots

[candid rivet]

if you add and substract cos³(3x) to the expression, you'll see that the function is actually equal to -2cos³(3x) (by using the fact that cos²+sin²=1)

which is equal to zero
iff cos(3x)=0
iff 3x=pi/2 +kpi
iff x=pi/6 +kpi/3=(1+2k)pi/6
where k is an integer

In conclusion you have only 2 roots (k=0 and k=1) in [0 ; pi/2]

@foggy torrent

[foggy torrent]

yeaah I got it

thank uu

[undone ledge]

can i please get some help wit this questionnnn

[remote saffron]

I hope it will help...

[remote saffron]

@undone ledge

[flat rain]

Can anyone help me 😭

[jade creek]

that means p(3) + 4 = 10 and -10

@flat rain

[bitter mica]

anyone taking pre-calc have any resources for the probabilities unit?

[elfin cradle]

check proffesor leonard, has a full free course on yt for precalc calc123, the best resource i have found for maths tbh

can someone explain to me why i cant just integrate the 3/2x+2 and get 3ln(2x+2)?

instead getting 3/2ln(2x+2)

and whats the rule that im missing

[plucky sail]

U = 2x + 2

du = 2 dx

du/2 = dx

[ebon relic]

hello guys , can somebody please help me with this everytime i do i get the answer 12 but in the answer list its 9

[foggy torrent]

could u send the full question

@ebon relic

[ebon relic]

i can but its in Azeribaijani

[foggy torrent]

qardas im from azerbaijan

[rustic sapphire]

hello everyone i am seeking help in understanding this example. [linear algebra]

[zealous swan]

Can someone explain why this makes sense?

How did it go from the first line to the second one

[left knoll]

can someone pls help me out with this?
answers are supposed to be
a) r-5
b) 10.6cm

I don't get it so if someone could please try a calculation and explain it to me, that would be much appreciated.

[south void]

Yo could someone help me with this excel equation, i can't figure out how I should transform the function like y=2,323x+3E+07 to y=2,323x+and than a numer (y). Help would really be appreciated.

[remote saffron]

Multiply both sides by (T/2pi)²

[remote saffron]

I Hope it helps

[jaunty plover]

Anyone free to help me with this?

[mystic thunder]

what's the answer

how come im getting 200 💀

[vagrant gale]

One message removed from a suspended account.

[vagrant gale]

One message removed from a suspended account.

[visual jackal]

Stuck on this question, gotten to
3a^4/3 - 24a^2/3 = -8

[vagrant gale]

One message removed from a suspended account.

One message removed from a suspended account.

[rocky moth]

do you still need it ?

[olive reef]

inverse trigonometric functions have many outputs for one input
so , how are they even 'functions' ? bcs functions have only one output for an input

[shell citrus]

F is not 90 degree? the straight angle is 180 and there is 83 outside so F should be equal F = 180-83 , F = 97

[brave lion]

I’m currently studying for calc 1/2 and i often find that i have issues connecting concepts or in general “thinking” in a mathematical way i’m mostly solving problems without knowing why or what i’m solving… Therefore when I find myself in a situation where the problem is not in a pattern i’m familiar with i struggle immensely to solve it and often use tools like wolfram to see the steps to the solution and be like “i think i get it” but the next time i see a similar problem i have a super slim chance of actually solving it… Same applies to theory if it’s something that can just be memorized it’s easy but deducing stuff from it and proof feel impossible to even start. This is also a big issue for my exams because I often just don’t have time to solve everything and i fail.
I’m planning on studying the subjects again from the ground up because I feel i’ve messed up my learning so much that even my notes are worthless and i feel like looking at them is a waste of time. I have my professors lectures, notes which are almost par to par with the textbook he recommends and two big workbooks. I know my question is subjective but what would you say are the fundamentals i should have and where to get them(textbooks etc.)? how should i approach the learning? mindset? notes? flash cards? i don’t have a lot of money but online courses or teachers? roadmaps? Everything is welcome and appriciated!!!!
In case it helps here are my textbooks (in italian sadly because that’s where i study but i have good academic english so it’s no issue to consume material in that language)
ISBN 883395684 vol 1&2

[shell citrus]

I dont have much of an advice but I think relearning is not the key here in this case, but may I ask u what text book or resource do you use for solving problems on calc 1

[jade creek]

ISBN 883395684 vol 1&2

[weak lotus]

lets say you have to solve integrals
what would i do?

sit down, just pen and paper, or ipad idk what you use.
just that with the exercises. no solution, like 0
work on every problem for a total of lets say 2/3h
if you get stuck, doesnt matter, try something else, somethign totally different (im talking about techniques here)
the most important thing, what i learned from a friend who went to the IMO, is to NEVER EVER GIVE UP

math is something unique, why? it has only 1 solution, but the fun things is that you can get there in different ways

your mind is capable of so many great things

just give it time to develop

best of luck

[violet rampart]

elp

help

watching a video on some vectors stuff. The question says that the wind is blowing NW yet the teacher draws the arrow going SE. I have no idea why ?
should I assume that everything works in opposites ? then why is the plane going north (sorry, im not the sharpest tool in the shed (yet)

could it be the from ????

my fear of getting roasted has given me a clue but i cant be sure

[violet rampart]

I GOT ITTTTT

[jade creek]

it come from northwesst

[visual jackal]

Possible, me and my brother got 21.16 as a, I can share working s wiht you if you want but it might be tricky to decipher

[visual jackal]

Nvm spotted your mistake, lower boundary of the integral is 8 not 0

When graphing the equation or setting it equal to 0 to solve for the x intercept it gives 8

Lmk what you get if you can be asked to try again!!

And lmk if I made a mistake too

[vagrant gale]

One message removed from a suspended account.

[visual jackal]

If you try and solve pls lmk what u get, we only started our integration topic last week but yeah

thjat question is worth 9 marks 😭

[elfin cradle]

Hey guys, do you have any course/videos recomendation for dynamic optimazation? like variational calculus. Example: F(x',x,t)=4xx'-5x'^2+3x^2(t)

Blackpenredpen/profesor leonard style videos if possible, but anything is good 🙂 thx

[jade creek]

F(x',x,t)=4xx'-5x'^2+3x^2(t)

is this multivariable calculus?

is it like a combination of multivariable and differential equations

[elfin cradle]

yeap i think it is

you have to differantiate acording to fx,fx' and fx't, then equalize fx and fx't and solve via a diferential calculus method

i know the theory, but i want more examples and stuff to practice

[vagrant gale]

One message removed from a suspended account.

[near trout]

Anybody plzz solve Q4 for meeee

[mystic thunder]

it's so rough Lmaoaoa tell me ill properly solve and send you

[near trout]

Yep thnx

[near trout]

Is 2/3 correct?

[tired aurora]

Let me know if you can’t decipher my scrawling

[frigid ingot]

Helppppp.... I have an examination in a few days

[remote light]

Can someone please help me with this?

Number 10

[zealous iris]

6x - x² + 2023
6(√24 + 6√15) -(√24 + 6√15)²+ 2023
= (6 x 28.13) - (791.49) + 2023
= 168.78 - 791.49 + 2023
= 1400.29

i think this is the answer

[remote light]

Thankss

[polar glade]

is it true

[remote light]

The thing is that I don’t have an answer key for that, that’s why I’ve been asking people

[left knoll]

exactly

[zealous iris]

ahh

mb bro

[remote light]

Thanks for your help, guys. Appreciate it

[zealous iris]

ur so smart ur so cool

[frigid ingot]

Dudeeee.... You made it look so easy

[frigid ingot]

Actually!!

[frigid ingot]

I did it your way using a calculator.... I got something like 2017.0231

Maybe you went wrong solving the under-root part

[polar glade]

9. 1?

[foggy torrent]

yess

[foggy torrent]

tysmm

[polar glade]

253?

[zealous iris]

ohh

thank you for letting me know 🫂

[left knoll]

can someone pls explain this? I dont understand how the answeris 151

[weak lotus]

calculate surface of total circle
calculate circle segment
subtract

[elfin cradle]

what would the result be of Fx't= 21(x(t^3)(x')) - 6x'

[weak lotus]

in case of PD's, here its with respect to x, so the rest you treat as a constant

so, even t is a constant

[frigid ingot]

Solution...

I don't really know if there's any fractional value for sin50... so i've used 0.76

[left knoll]

How would one do this? I’m really confused

It wants angle E

[mystic thunder]

In ∆ BCE, it is given that:
EC = BC
therefore,
angle CBE = angle CEB (angle opposite to equal sides are equal).
now find angle BCE.
on like AE we use the property of linear pair
angle ACB + angle BCE = 180
=> angle BCE = 110°
apply angle sum property of a triangle in ∆ BCE
angle BCE + angle CBE + angle CEB = 180
110+ 2( angle CEB) = 180
2( angle CEB) = 70
angle CEB = 35°.
Now angle E = angle CEB + angle CED,
angle E = 35+ 50
= 85°.

lmk if you want me to explain any step

[foggy torrent]

thaaank uu smm!!!

[limpid pecan]

i can try

[mellow mesa]

Send the problem, worth a try.

[left knoll]

I appreciate ur help to begin with, many thanks, im guessing angle e = 50 + 35 because angle e is the entire right bottom corner? like this?

[limpid pecan]

yes

[left knoll]

👍

[trim shuttle]

I guys i really need some help, the question says: find the equation of the hyperbola having r: x+3y=1 and s: x-6y=3 as asymptotes.
thanks a lot! ❤️

[limpid pecan]

In the third question why is the option(A) wrong

[mystic thunder]

yes you're correct

[tardy crypt]

how do you integrate 1/a^x dx ?

a is constant

[dreamy radish]

ln|a^x| = xln|a| + c

[dreamy radish]

a in this case turns into a function of x here i believe:)

[tardy crypt]

Aren't we supposed to use logarithmic functions or exponential to solve this? Well derivative w.r.t x of xln|a|= ln|a| so that cannot be the right answer

Remember a is any constant

[dreamy radish]

well, although derivatives are the opposite of integrals, in some cases we arent able to get the absolute values when changing from derivative to an integral in the case of indefinite integrals

[tardy crypt]

Hmm can you solve one example , integrate 1/(8^x) w.rt x

[dreamy radish]

its the same answer, xln|8| + c

[tardy crypt]

So you mean to say the constant C is representation of what's missing

[dreamy radish]

yup

thats it:)

[dreamy radish]

lets say, we find the derivative of xln|a|

w.r.x

its x/a + ln|a|

theres some complex calculations from this point forward, but the value will be similar to 1/a^x

and for the missing part, we add the c

[tardy crypt]

But i don't understand why you are treating ln|a | as a function of x because it's not, it's simply a real number , it could be 4 ,
Derivative of xln|4| is simply ln|4| not x/4 + ln|x|

[dreamy radish]

once to ingtegrate this again, i mean

[dreamy radish]

ln|4| is treated as a logarithm function

not a constant

i get where you're coming from, but derivatives here will follow the uv method

where x is a algebric and ln|4| or ln|a| is a logarithmic function

[tardy crypt]

I'm still doubtful that we are supposed to use the product rule for xln|4|,
As far as i know derivative indicates change w.r.t something but ln|4| is constant hence the change is 0 w.r.t anything

[tardy crypt]

Can you elaborate or prove that the derivative of ln|4| w.r.t to x is not zero?

[dreamy radish]

the derivative of ln|4| wrt x is indeed 0, but the derivative of xln|4| isnt

since x here is in multiplication with ln|4|

it turns xln|4| into a function of x

similar to 3x, 4x etc

[tardy crypt]

But the derivative of 3x is simply 3 w.rt x

[dreamy radish]

look, the derivative of ln|x| is 1/x

this, is a function of x

this is a formula, as you may know

[tardy crypt]

To use product rule u and v both u and v needs to be functions of x if derivative w.r.t x i.e u(x) and v(x) isn't that right?

[dreamy radish]

okay, your making it extremely complex, more then it is

ln|4| is a constant, and xln|4| is a function of x

and since, the 4 here, is in a logarithm function, you cant just treat it as a you would a 3, 4,

math majors, help?

[mellow mesa]

What are you guys talking about

[dreamy radish]

i think my brain is not enough to figure out a proper answer without getting confused

[dreamy radish]

scroll up a bit

im willing to apologize if im wrong, but please double cross my words

[mellow mesa]

So the problem is to find the derivative of 1/a^x?

Oh anti derivative

[dreamy radish]

the ingetral of 1/a^x

[mellow mesa]

Forgot to add the constant of integration sorry.

[dreamy radish]

thanks:)

[next kraken]

2+2?

[mellow mesa]

Too difficult for me. sorry chief

[next kraken]

f*** thx anyway, i think im gonna have D-

[keen patio]

How can I solve this question

[polar glade]

3k-11=4p, p natural number
3k-11=4
3k=15
k=5

[left knoll]

im guessing b = 4 because of this?

[hollow moth]

no i don' think so i think if we multiply 4 with these values we get the normal cos diagram

for example in this diagram we see 90 degrees is equal to 5 which if 1 if we divide it to a

normally 90 degress should be equal to 0 but we multiply it with 4 so we get 360 degress

and it equals to 1

you can try it on other numbers

sorry if i couldn't explain well i am not used to explain math in english

[wild gull]

that's the idea basically

[wild gull]

the graph you have on there has a period of pi/4, or 90 deg

whereas normal cos has a period of 2 pi, or 360 degrees

whenever you have an equation of the form y = acosbx, it gets taller by a factor of a, and the period is shorter by a factor of b

so multiply 1 by a, there's your magnitude.
divide 360 by b, and it's your period.

[fierce spindle]

Can someone help me in a question of trigonometry?

An electrical cable must be taken from a pole A to a pole B over a channel whose width is 10m as shown in the figure. The distance between posts A and B is very long, an auxiliary pole C will be used. Knowing that the cost of cabling over the river is $ 100.00/meter and over land is $50.00/meter, mark the expression that allows you to determine the total cost of this cabling depending on the angle indicated in the figure.

Here's the image containing the possible answers and the electrical cables:

[fierce spindle]

Didn't found that answer. Somethow its automatically setted to mark the first option.

[fierce spindle]

Also, this is the automatic translation of the question/exercise. If the errors impair the understanding of the text, I'll change it to help the one who is solving it.

[candid rivet]

tell me if you need more detailed explanations (:

[candid rivet]

also if you just want to quickly guess the right solution, by only calculating the length AC you'll see there is a 1/sin(x) factor, which only appears in the third solution

[fierce spindle]

Found my error. I just used the value of (sinx/10*cosx) as HC instead of inverting it while doing my solution. Thanks A LOT mate.

[fierce spindle]

You're right. Again, THANK YOU A LOT.

[fallow topaz]

i need help with multiplication of matrix

anyone?

[candid rivet]

the same logic works for bigger matrixes (like picking the right lign of the 1st matrix, and the right column of the 2nd matrix)

for matrixes of size n you then get the formula

And to quickly remember the formula, notice how the i and j are placed :
i always at the most left/beginning
j always at the most right/at the end

and practice ! Do some matrixes multiplication so it feels natural (:

[vestal spoke]

In this laplace transform can anyone explain how we got s^(n+1)? Why is it not s^n?

[vestal spoke]

Okii i solved it. Thank you so much!

[signal nimbus]

What was the solution?

[vestal spoke]

So if u go furthur down the solution. We have to solve for laplace transform of t^0 at some point. Which gives us 1/s. That's where the extra s came from

I was so confused frfr

@signal nimbus oop i forgot to @ my apologies

[signal nimbus]

All good!

[signal nimbus]

I see now, thank you!

[vestal spoke]

Another poblem of laplace transform how do we do this?

[hard hawk]

Hey can anyone help me with a 2-variable limit?

(tag me if you answer)

[left knoll]

In SPSS: The proportion of measurements with a high NO2 concentration (>16 μg/m3) in previous years was equal to 60%. Is the proportion of measurements with a 'high' NO2 concentration after the traffic campaign significantly different from the proportion of measurements with a high NO2 concentration in previous years? Check at a 1% significance level.

How do i do this in SPSS?

[random pecan]

can someone explain why option D one of the answers? I understand that B and C are isosceles triangles but not D

[polar glade]

if x=7
y=5
perimeter=12+z
2<z<12
14<z+12<24

[random pecan]

but where did the two come from?

[digital birch]

the formula is called triangle inequality. I think she was going to throw this away

[polar glade]

oh yes

[random pecan]

i see, thank you

this makes more sense to me

[jolly basin]

hi can someone explain this scatterplot diagram to me?

[hardy mason]

Hey guys ,does anyone know how can i prove that this equation is true for every x>0 ?

[ancient epoch]

you could write e^-x as 1/e^x

with the x multiplying in the front, now you have the fraction x / e^x

e^x is always greater than x for every x>0, since e^x is an exponential function, e being equal to approximately 2.71, so e power x will always be greater than x

thus, the fraction of x/e^x is a proper fraction, which means its value is less than 1

[hardy mason]

This is true only if x>0 right? Because I’m trying to think of a case where it wouldn’t work and all I can think about is when x<0 and if x=0 the equation will just equal one

[left knoll]

how would u do this?

[tacit cradle]

x + 5 = r
r^2 = x^2 + 9^2
?

[elfin plume]

Does anyone know how to solve this problem?

[deep edge]

A plleasant day everyone! I just want to know if some of you guys have any ideas how to solve a taylor series?

[elfin plume]

I was thinking of doing series solution today but went with vector calculus. I have my exam the day after tomorrow. Also we only have power series in the current so I'm not doing Taylor series😕

[proper venture]

Hello