#help-28

1 messages · Page 246 of 1

vapid notch
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Yeah

sturdy fern
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why theta + 60

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why bnot just 60

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i thought angles were same?

bright bronze
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the argument angles are wrt real axis

vapid notch
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argument is w.r.t the +x axis

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yeah the real axis

sturdy fern
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oh z1 okay yh cuz it dont start from the x axis

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what angle does z2 have?>

bright bronze
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some theta

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you dont need any specific value

sturdy fern
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oh yeah i was looking at angles inside the triangle but im supposed to look at the rotation

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alright

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but how do we link them toegtehr now

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maybe since r1 is equal to r2

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we can split up the z1?

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since z1 would have the same components

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so we would get

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z2 * e^i pi/3

vapid notch
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yeah you’re on the right track

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thats equal to z1

sturdy fern
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yh, alright for ii?

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so i plug it in

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and i get z2^2 ( e^i 2pi/3 + 1)

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but here i get stuck

bright bronze
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can you write (e^i 2pi/3 + 1) in the form a + bi?

sturdy fern
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so e^i2pi/3 is -1/2 + (sqrt3/2)i

bright bronze
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yea

sturdy fern
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so we add one, that would just give us 1/2 which is in first quadrant. so pi/3?

bright bronze
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yep

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e^i 2pi/3 + 1 = e^i pi/3

sturdy fern
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oh there we have the z1 term again

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alright guys thank you so much

bright bronze
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np

vapid notch
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yw

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.close

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you should do that

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unless you have more to ask

sturdy fern
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.close

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golden shore
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Put your hands up now!

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golden shore
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NYPD!

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Go -5 units towards the right

golden shore
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Ridiculous

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Ridiculous

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Ridiculous

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That’s unacceptable

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For me

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Define -5 units towards the right

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That’s idiotic

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That’s not right

onyx glen
golden shore
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I cannot accept that expression

hoary ember
golden shore
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I can’t never accept it

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I would rather die

onyx glen
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english doesn't do double-negatives btw

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but also you are being quite over-dramatic rn

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it is a strange turn of phrase but "go -5 right" is very easy to reinterpret as "go 5 left"

narrow path
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but what you gonna do

onyx glen
golden shore
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I’m so sad at the fact that teacher might put this double negative expression on kindergarten question

narrow path
golden shore
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They are just kids!

spiral elk
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bro ong im seeing red reading this wtf

narrow path
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when i see red RUN.

spiral elk
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🐺

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🦅

hoary ember
onyx glen
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see red run i, WHEN.

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vapid notch
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thick hedge
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thick hedge
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Would like to do this using Lagrange interpolation

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$\frac{x+1}{1} + \frac{(x+2)(x+1)x}{ 70}$ would be a degree 3 interpolation

glossy valveBOT
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What a wonderful world !

thick hedge
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oops

onyx glen
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would not be lagrange tho

thick hedge
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the interpolation would be $\frac{(x+2)(x+1)x(x-1)(x-2)(x-3)}{ -5 \cdot -8 \codt -15 \cdot -20 \cdot -17}$

glossy valveBOT
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What a wonderful world !

the interpolation would be $\frac{(x+2)(x+1)x(x-1)(x-2)(x-3)}{ -5 \cdot -8 \codt -15 \cdot -20 \cdot -17}$
```Compilation error:```! Undefined control sequence.
<argument>  -5 \cdot -8 \codt 
                              -15 \cdot -20 \cdot -17
l.1422 ... \cdot -8 \codt -15 \cdot -20 \cdot -17}
                                                  $
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.```
onyx glen
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applying lagrange on this is gonna be kiiiinda painfu-

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what?

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are you sure about this

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thats a 6th degree poly

thick hedge
onyx glen
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m

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you bungled it severely

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also i will just say this

thick hedge
onyx glen
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lagrange interpolation BY HAND

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is going to be mega ass

thick hedge
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I know, but during my last viva I was asked to do it by hand for a data set

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so not taking any chances this time

onyx glen
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how big was the data set

thick hedge
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Atleast 4-5 points

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I think I should chose a smaller data set

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do thse number work

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wiat

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oops

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okay, this works

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f(0)=2, f(1)=2.75, f(2)=4?

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not that it matters here

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$L_0(x) = \frac{ (x-2.75)(x-4)}{ (2-2.75) \cdot (2-4)}$
\
$L_1(x) = \frac{ (x-2)(x-4)}{(2.75-2) \cdot (2.75-4)}$
\
$L_2(x) = \frac{(x-2)(x-2.75)}{ (4-2) \cdot (4-2.75)}$

glossy valveBOT
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What a wonderful world !

thick hedge
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And Then I use the fomula $\sum_{i=0}^{2} f(x_k) L_k$

glossy valveBOT
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What a wonderful world !

thick hedge
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right

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elder fiber
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.

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@civic quarry

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elder fiber
glossy valveBOT
elder fiber
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Finally

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Should I show the question as well

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Yeah

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Wait

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,rotate

glossy valveBOT
elder fiber
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,rotate

glossy valveBOT
elder fiber
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,rotate

glossy valveBOT
elder fiber
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Q18

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Hello?

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You there

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Yess

glossy valveBOT
elder fiber
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Hmm okay

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Thank u

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manic cape
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150X=35 MOD 31

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manic cape
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so here i can say 150x=4mod31

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what would be next step?

narrow path
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do you mean congruent to

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with the 3 lines

void nova
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!occupied

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lyric tusk
# manic cape 150X=35 MOD 31

since (a,31)=1 for every a is positive integer where a≠31 So
divided both side by 5 you’ll get
||30x con 7 (mod 31)|| and since
||30x con (31-1)x|| con ||-x con 7 (mod31)||
thus
||x con -7|| con ||24 (mod 31)|| as required

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warm quiver
#

'following the diagram, if the coefficients of friction are 0.4 and 0.5, what is the minimum value of applied force F to start movement of the system?'

the hanging body is 1 kg, middle is 2 kg, right is 3 kg.

by coefficients are 0.4 and 0.5, this means that the static coefficient is 0.5 and the kinetic coefficient is 0.4 (its a bit strange but this is how the questions are written, others are like this)

also assume g=10

now the intended answer is 35N, which i got but not quite. i treated the whole system roughly as one body. trying to find the point at which net force = 0 when friction is in play to find the point at which movement begins.

the hanging mass to the left is pulling on everything, with a force of mg or 10N. next, the friction forces for each of the two boxes on the surface. for the 2kg mass, 0.5 x 20 = 10N. same for the 3kg mass, 0.5 x 30 = 15N.

add it all up, i got 35 N going to the left. now the force must be 35N in the other direction to counteract start movement.

however, the force is inclined at 53 degrees. breaking up the force, i got F x cos53 for along the horizontal line. rounded this to 0.6F.

so i take this to mean 0.6F must be greater than or equal to 35N, meaning F is roughly 58.3. however, the given answer is just 35N.

did i do something wrong? or am i correct? (usually im wrong)

vernal perch
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I checked seems like 35 to the right is the right answer

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I would guess the question just mixed up the answer

warm quiver
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dawn hinge
#

Here I am trying to prove equality for the first case when f is injective. Is it sufficient to take the contrapositive of "If f is injective then equality" meaning if I prove that "Not equal then f is not injective "

dawn hinge
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Also I'm having doubts about whether I correctly stated the contrapositive

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dawn hinge
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It's from Munkres' Topology

dawn hinge
onyx glen
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actually idt going for the contrapositive is a good idea at all.

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orrr

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no you can make it work actually it's not that bad

dawn hinge
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assuming it's equality without injectivity then showing a contradiction?

onyx glen
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when $S \subset T$ but $S \neq T$, it implies there exists a point in $T$ that doesn't belong to $S$.

glossy valveBOT
onyx glen
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though... actually

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we have to be a bit more careful

lime ether
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why not just do it directly

onyx glen
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yeah i guess

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do it directly and worry much less about quantifiers as i was about to write

dawn hinge
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Alright👌

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!close

lime ether
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not quite

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!done

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dawn hinge
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Ah thank you

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I'm still very new

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!done

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lime ether
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no worries

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😭

dawn hinge
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dawn hinge
#

😆

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.close

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unborn acorn
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gritty rose
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use definition of derivative

unborn acorn
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ok

unborn acorn
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if the first question is about differentiability and not derivability

fast peak
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what do you think the word differentiability means

unborn acorn
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i know that derivability implies differentiability but not always the otehr way?

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orr

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for question 1, do i only need to show that the partial derivatives exist and are continuous on C?

gritty rose
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one of the first two equations

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finding df is a little harder

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oh not that much harder. if f(x, y) = u(x,y) + i v(x,y) then

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chilly pecan
#

can you explain why a/b has to be between 1 and 2 for dimpled cardioid like $a+b\cos(\theta)$

glossy valveBOT
#

Odd_the_Wolf

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winter patio
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winter patio
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ok cus im confused w these lns

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i know they base is e

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so do i do

rough tundra
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(\log_b(a)+\log_b(c)=\log_b(ac),\quad a,c>0)

glossy valveBOT
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PajamaMamaLlama

winter patio
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Ln(x+4)(6-x)

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(\ln_e(x+4)+\ln_e(6-x)=\ln_e(x+4)(6-x),\quad a,c>0)

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can u do that

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does that work

rough tundra
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indeed it is true that (\ln(x+4)+\ln(6-x)=\ln((6-x)(x+4)))

glossy valveBOT
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PajamaMamaLlama

winter patio
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but im confnused about the ln(21)

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what am i doing with thta

rough tundra
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well if that log of (6-x)(x+4) is equal to the log of 21, then (6-x)(x+4) must be equal to 21 itself, yes?

winter patio
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so we remove the ln?

rough tundra
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right, mathematically that is, (\ln((6-x)(x+4))=\ln(21)\implies (6-x)(x+4)=21)

glossy valveBOT
#

PajamaMamaLlama

rough tundra
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where that long arrow is read as "implies"

brazen stirrup
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I sense the quadratic formula

winter patio
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me too

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ok cus

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i have

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-x^2-2x=24

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we have to do quadratic cus we cant factor cus the x^2 is negative right/

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sorry +24

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not =

rough tundra
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we can factor

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since -x^2-2x+24=0 ==> x^2+2x-24=0

winter patio
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ohhh

rough tundra
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wait

winter patio
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oh yeahhh why if forgot basic math

rough tundra
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did you expand that right?

winter patio
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did i?

rough tundra
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oh wait

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-x^2-2x+24=21 pardon

winter patio
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OH YEAHHH

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these are literally the mistakesi make on my exams

rough tundra
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happens to everyone :) practicing usually helps with that

winter patio
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so now i havd

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x^2+2x-3

rough tundra
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then we find two numbers that add to 2 and multiply to -3

winter patio
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3 and -

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1

rough tundra
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indeed

winter patio
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so we have x=-3, and 1

rough tundra
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hang on

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I believe you did expansion wrong: (6-x)(x+4)=-x^2+2x+24=21

winter patio
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omg i did

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So it’s reverse

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3 and -1

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digital mica
#

hello! i need help with this problem

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digital mica
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i don't know why in step 3 the bottom part of the fraction gets canceled out

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and why in the 5th step the (x+4) just dissappears

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<@&286206848099549185>

steel nest
digital mica
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i think: radical ecuations that get reduced to second grade

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i'll send u the other part

steel nest
digital mica
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i do understand this one

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steps 6 and 7

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yes

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the problem is getting solved

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but i dont understand steps 3 and 5

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why the denominator in step 3 and the x+4 in step 5 just get wrecked

steel nest
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gimme a minute or two to try to parse the algebra

digital mica
#

for sure, tysm

steel nest
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I think i understand the manipulation done here

digital mica
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lemme see

steel nest
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for step 3 if the denominator is not 0 then you can multiply it on each side of the equation and on the right side it will be eaten up by the 0

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so implicitly it is assumed here that x is not 3,-4,or -5

steel nest
digital mica
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i see

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so

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it can happen with any given denominator when the equation is =0?

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cuz u multiply it on each side

steel nest
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you can do this simplification when the denominator is not 0 yes, you might have to check the neglected cases x = 3,-4,-5 separatly

digital mica
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and does this happen also in step 5??

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just the inverse

steel nest
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yep

digital mica
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u divide each side of the equation

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omg it makes so much sense

steel nest
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you can divide if it’s not 0

digital mica
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wait

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but it is 0...

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look

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right here

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i dont know what happened there

steel nest
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no to get here we already assumed in step 3 that x is not -4

digital mica
#

wait wait, but why is that we assume that x cant be -4,-5 or +3??

steel nest
# digital mica

but then in step 5 there are two possible cases for this equation to be equal 0. either x=-4 it can’t because step 3, or the other expression is 0, what’s hilighted in yellow

digital mica
#

oh

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i think i get it

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so its like u get 2 different equations =0 for each parenthesis

steel nest
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i mean one equation for each equal to 0

digital mica
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yes

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i thought it was one whole equation

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okay i have one final question

steel nest
digital mica
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about the x that cant be +3,-4 or -5

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why is that?

steel nest
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because if x equals one of these 3 values, we would divide by 0, and this operation is undefined

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you just can’t divide by 0

digital mica
#

that is right

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so

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u cant divide by 0

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so

steel nest
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in these case some other simplification might happen if it’s important to take care of these cases

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you have to solve another way using the fact that x = 3 for instance

digital mica
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basically x cant be the number that's next to it with the opposite sign

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when in the denominator

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in this type of problems

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=0

steel nest
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yep

digital mica
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alrighty, that would be all

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have a nice afternoon, thank you very much

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really appreciate it

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❤️

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stuck sleet
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.reopen

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stuck sleet
#

Hello, I speak Spanish. Can someone help me solve this please?

stuck sleet
#

<@&286206848099549185>

placid oak
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does the overbar mean it's a number?

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for example \overbar(abc) where a = 1, b = 2, and c = 3, would be 123?

stuck sleet
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yes

placid oak
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what have you tried?

stuck sleet
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Sorry, I got the exercise wrong.

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I have resolution problems with this

placid oak
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Ok, what have you tried with this one?

stuck sleet
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I have tried and come to the following conclusions: a is greater than c; z is greater than c; y is greater than b

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Since they must all be one-digit numbers and a and c must be different from 0, the only numbers that meet this requirement would be a as 7, c as 3, and z as 4.

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By replacing the values ​​the subtraction would be contradictory

placid oak
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have you tried writing \overbar(abc) as 100 a + 10 b + c, and solving algebraically?

stuck sleet
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no

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My teacher in class taught us something like the minuend plus subtrahend plus subtraction equals two minuends.

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I don't know if that is useful

placid oak
#

try that with your example

glossy valveBOT
placid oak
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A, B, and C are all numbers, not the digits in a number

stuck sleet
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look at this

#

estos son los unicos valores que cumplen los de 56 pero no cumplen la resta

#

Have you managed to solve the problem? I've started to think it's poorly stated.

placid oak
#

to be honest, I'm not sure of any smart ways to solve this, other than getting a computer to brute-force through every combination until it finds something that works.

stuck sleet
#

creo que el problema esta mal porque yo intente lo de la computadora

#

I think the problem is wrong because I tried the computer thing.

placid oak
#
from itertools import product

def num(*digits):
    buffer = 0
    for digit in digits:
        assert 0 <= digit <= 9, "Error: digit is not base 10."
        buffer = buffer * 10 + digit
    return buffer

def find_solution(verbose=False):

    for a,b,c,y,z in product(range(10), repeat=5):

        if verbose:
            print(f"Trying a={a}, b={b}, c={c}, y={y}, z={z}")

        if not (a > c):
            continue

        if not (a**2 + c**2 - z**2 == 56):
            continue

        if not (num(a,b,c) - num(6,y,z) == num(c,b,a)):
            continue

        return a,b,c,y,z

solution = find_solution(verbose=True)
if not solution:
    print(f"No solution found :(")
    exit()

a,b,c,y,z = solution

print(f"\nSolution Found!")
print(f"a={a}, b={b}, c={c}, y={y}, z={z}")
print("")
print(f"{a}{b}{c} - 6{y}{z} == {c}{b}{a}")
print(f"{a}^2 + {c}^2 - {z}^2 == 56")
stuck sleet
#

?

placid oak
stuck sleet
#

do you execute it?

placid oak
#

Maybe you can write it as \overbar(abc) = 100a + 10b + c for every number, and solve algebraically

#

which I mean, find a simple algebraic expression, and then keep trying values until one suceeds

#

or not, there may be too many values to try

#

I'll give you a hint, c = 1

stuck sleet
#

Bro, if there is an answer, since I'm feeling unmotivated because I think there is no answer.

placid oak
#

there is an answer

stuck sleet
#

It's okay, I'll keep trying.

stuck sleet
placid oak
#

I can't see where you'd use it

placid oak
stuck sleet
#

Do you know how to program, bro?

#

Bro, do you know any way to solve it mathematically since I have to make a solution for my notebook?

placid oak
#

I'm working on that one XD

#

you can rewrite the equation into $$99(a-c) = 10y + z + 600$$

glossy valveBOT
placid oak
#

then, treat a - c as it's own digit.

#

Let $x = a - c$. Then $$99x = 10y + z + 600$$

glossy valveBOT
placid oak
#

This is as far as I've been able to reduce it.

stuck sleet
#

esto debera tener una utilidad si lo usamos?

placid oak
#

Ah, I've seen something

stuck sleet
#

This should have a use if we use it?

placid oak
#

$$99x = 600 + 10y + z = \overline{6yz}$$

glossy valveBOT
placid oak
#

So 6yz is a multiple of 99

#

this should easily tell you what y and z are

#

which should allow you to easily tell what x is

stuck sleet
placid oak
stuck sleet
placid oak
#

there's only 2 options for a and c, only one of which will fit the second equation

#

hope this helps 🙂

stuck sleet
#

Okay bro, I'll keep trying and I'll give you the solution.

placid oak
#
  1. Use \overline{abc} = 100a + 10b + c to expand the first equation.
  2. Simplify to get 99(a-c) = \overline{6yz}
  3. Recognise this means the RHS is a multiple of 99, and solve for y, z, and (a-c)
  4. Write out all possible combinations of a and c using the solution for (a-c)
  5. Use the second equation to determine which we need to use
stuck sleet
#

99(a-c) = 600-10y-z*

placid oak
#

plus

stuck sleet
#

I think it's because the negative sign comes before the 600+10y+z.

#

I should put parentheses

#

I have come to the conclusion that x equals 7. How could I continue developing the resolution?

#

@placid oak

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#

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#

@stuck sleet Has your question been resolved?

half ibex
stuck sleet
stuck sleet
#

here

#

We found the values ​​of the unknowns with a Python code that tested all possible numbers, but I need the mathematical solution.

stuck sleet
hearty sandal
#

Xd

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@stuck sleet Has your question been resolved?

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hoary ember
#

how can you prove (a)?

full forumBOT
fervent owl
#

if x is an 11th power mod p use FLT to deduce something about x

hoary ember
#

well by flt x^{p-1}=1 mod p

#

you can write it as (x^11)^k=1 mod p

fervent owl
#

so if x is not 0

#

an 11th power is a root of x^k - 1 = 0 mod p

#

so how many of them are there?

hoary ember
fervent owl
#

so let's say x is an 11th power

#

x = y^11

#

then x^k = y^(p-1) = 1 mod p

#

so x^k - 1 = 0 mod p

hoary ember
#

oo

#

is it k

#

cause a power-k polynomial has k solutions right

jolly ferry
#

the third one, idk if I used the right formulas, is it correct to use the liner interpolation to find r?

hoary ember
#

or is this completely unrelatsd and im dumb

fervent owl
hoary ember
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fervent owl
#

tbh the thing i guided you through only gives you that it has at most k solutions

#

which for the most part still motivates why we should pick primes that are 1 mod 11

#

anyway if you wanna prove that there are exactly k+1 11th powers, use the fact that we have a primitive root mod p

hoary ember
#

oh so basically the reason your finding p≡1 mod 11 is to find p with as little ranges for x^11 mod p?

hoary ember
#

oo

#

ok then the smallest prime is p=23

fervent owl
#

but anyway if that doesn't work you'd try 67 instead

#

anyway knowing how to choose moduli is a really useful trick to know about

hoary ember
#

a^11+11b^11+19c^11=0 mod 23 hmm

hoary ember
fervent owl
#

another question i have in mind is

#

do there exist integers x,y, such that x^3 + y^4 = 2015^2015

#

(i think it was 2015^2015 at least)

#

and also is there a positive integer n such that n^7 - 77 is a fibonacci number

hoary ember
#

wtf 💔

#

btw (cheating with calculator) x^11=0,1,22 mod 23, is there a way to find that?

#

cus with that i think you can solve the question with that as x^11=0 mod 23 is when 23|x t

fervent owl
#

so x^11 can be 0, +-1

hoary ember
#

uhh what

#

how can it be 0

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#

@hoary ember Has your question been resolved?

hoary ember
#

oh wait

#

.csolved

#

.solved

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blissful ledge
#

△ABC is an acute triangle, P is a point on the circumcircle Γ of △ABC, and line PB and PC are tangent to Γ. ∠BPC=θ, what's the value of cos A (in terms of θ)?

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#

@blissful ledge Has your question been resolved?

tiny salmon
#

connect OB, OC

#

OB is perpendicular with BP and so are OC and CP

#

therefore <BOC = 180-theta

#

and <A= 180-theta/2

blissful ledge
#

Oh I got it. Thanks.

#

close.

#

I hate geometry.

#

close.

alpine pecan
#

. close

rose yew
#

.close

sullen hinge
#

.close

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median gust
#

I know the answer is correct because I saw the answers, but is my proof right as well?

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dusky girder
#

HELP I DONT GET THIS

full forumBOT
slate violet
dusky girder
#

after letting t=tanx

#

they skipped a step

slate violet
glossy valveBOT
slate violet
#

a is a constant

dusky girder
#

ohhhhh

#

oh ok thanks

#

it's midnight here and my brain is missing neurones and my exam is tmr so im low-key panicking

#

i usually use θ

#

thanksss

dusky girder
#

thank you

#

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drowsy plover
#

can anyone help me on how to differentiate a complex function

(2z^2 + i)^5

z= x +iy

fast peak
#

do you have to do it from first principles?

#

or are you allowed to use differentiation rules

drowsy plover
#

teacher said i cannot differentiate the way we differentiate real functions

fast peak
#

so what are you allowed to use

drowsy plover
#

first principle and differentiation rules

fast peak
#

so you are allowed differentiation rules but not the usual differentiation rules you know from real functions?

drowsy plover
fast peak
#

which rules are you allowed to use

onyx glen
#

dear lord that's gonna be so ass if you have to do it from first principles

onyx glen
drowsy plover
fast peak
#

multiply it out then

fast peak
#

binomial theorem

onyx glen
#

so (f+g)' = f'+g' is forbidden?

onyx glen
drowsy plover
#

i forgot how to differentiate complex function

fast peak
#

the whole point is that you differentiate complex functions the same way as real functions

#

there is nothing special to do

drowsy plover
#

ohh thanks

fast peak
#

but you seemingly arent allowed to do that

drowsy plover
#

i asked friend of mine he said we cant do it the way we differentiate real ones

#

as teacher said it earlier

hidden harbor
#

you should have a more clear definition of "not like real ones". As in, which properties in particular you're allowed (or not) to use

drowsy plover
#

binomial and cr eqn will be enough

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safe plaza
#

Let's say we have a function like this:

x+2 = y

Now, is "x+2" called definition, and is "y" called output?

For context, I'm making a graph renderer and looking for appropiate names for my variables

safe plaza
#

I've also heard that "x+2" should be called "expression", but not sure if it's correct

short tinsel
safe plaza
#

that seems good, thanks

fast peak
#

the whole thing is the definition of the function

#

at that point you might aswell just call it formula

rapid rain
#

x+2 would more likely be the called the expression/formula of the function

safe plaza
fast peak
#

I mean in the end you have to live with your code

#

I would start to question the whole setup. why do you need an output variable, its just gonna be y all the time, no?

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thick hedge
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thick hedge
#

nvm

#

I'll do it later

#

slppey

#

eepy

#

.close

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torn jolt
#

for finding domain and stuff , when to use wavy curve method and when to use intersection ( like writing out diff ineqalities and taking intersection)
i need a generalisation on this
( im having very bad brain fog rn , so i cant really pull things together :/ )

alpine pecan
#

its basically the same thing
if u r given many functions
u use wavy curve for the functions, then use the intersection part on them all

#

ull get it with more practice

torn jolt
#

.close

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static verge
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static verge
#

why should discriminant be less then 0 for c

robust slate
#

You want the condition for invariant lines to fail

#

You showed that the condition is equivalent to that quadratic having (real) solutions

#

No invariant lines -> condition fails -> quadratic has no real solutions -> discriminant is negative

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shut trellis
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shut trellis
#

how do I find that angle?

quiet depot
# shut trellis

extrapolate the weight vector to form a right triangle. Sum of the angles in a triangle are 180, and the intersection between the ground and the weight vector is 90 degrees, so the angle you're looking for is 90-theta

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swift bridge
#

How are we able to combine $f(x+h) - f(x)$ into a single series?

glossy valveBOT
swift bridge
#

Like it seems we just somehow drop the limits

gritty rose
#

you can combine by the Weierstrass M-test

#

the terms inf f(x) and f(x+h) converge uniformly so the sum can be done term by term

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swift bridge
swift bridge
#

Like isn’t that still possible since both series converge?

swift bridge
#

To add term by term wise

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plucky aurora
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plucky aurora
#

Is the answer number 2?

gloomy lance
#

Perhaps

#

Can you say why it would be number 2?

plucky aurora
#

I put it in my calc and its the closest looking one

#

💀

gloomy lance
#

are you allowed to use calc at all times?

plucky aurora
#

On my test its taken away

#

@gloomy lance can u explain how pie effects a graph

gloomy lance
#

This isn't something exclusive to pi, any other number in the place of pi/4 would change the graph

#

in general, a function y=f(x) will have a horizontal shift when you apply f(x+a)

#

f(x+a) if a is positive will shift the graph to the left, if it is negative it will shift the graph to the right

#

f(x+3) shifts the function's graph to the left by 3 units

plucky aurora
#

And x-3 moves the graph to the right

gloomy lance
#

exactly

plucky aurora
#

Alr so here its a fraction

#

Positive frac

#

So it goes to the left

gloomy lance
#

so if we have f(x)=tanx, then f(x+pi/4)=tan(x+pi/4) shifts the graph of tanx to the left by pi/4

gloomy lance
plucky aurora
#

But how much is pie over 4

#

Idk how much to move

gloomy lance
#

pi/4 is just pi/4

plucky aurora
#

🗿

gloomy lance
#

you move pi/4

plucky aurora
#

O they all over 4

#

So jus move 1 to the left?

gloomy lance
#

you take the original points and subtract pi/4 from them

#

for example, the point at x=0 will be shifted to x=-pi/4

plucky aurora
#

Yea

#

So

#

Move 1 to the left

#

And das why its number 2

gloomy lance
#

yes

plucky aurora
#

Alr now what if

#

The negative was on the outside

#

Instead od x

gloomy lance
#

what do you mean

plucky aurora
#

Like negative tan x

#

Does it still go to the right

gloomy lance
#

-tan(x) would flip the graph

#

,w graph tanx

gloomy lance
#

,w graph -tanx

gloomy lance
#

think of it as flipping upside down

#

like the graph of x²

#

,w graph x²

gloomy lance
#

,w graph -x²

plucky aurora
#

Wait upside down or side to side

gloomy lance
#

upside down

#

in this case it also makes sense to think of it as flipping to the other side

plucky aurora
#

So a negative infront of the tan or log or wtv

#

Flips it upside down

gloomy lance
#

yes

plucky aurora
#

Ok so

#

It would he number 1

gloomy lance
#

you sent the same picture as before

plucky aurora
#

Yea

gloomy lance
#

ah i see

plucky aurora
#

The question was jus about negative

gloomy lance
#

yes -tanx would be number 1

plucky aurora
#

In the front of tan

#

Alr thx

gloomy lance
#

yw

plucky aurora
#

What does this mean

#

@gloomy lance

gloomy lance
#

What, period?

plucky aurora
#

Yea

gloomy lance
#

The period of a function is the distance at which the function starts repeating itself basically

plucky aurora
#

Oh

gloomy lance
#

For sinx and cosx that would be 2pi, for tanx its pi

plucky aurora
#

So dis is tan

#

So its jus pi

#

Ooo

gloomy lance
#

The formula for the period of tan(a*x) would be pi/|a|

plucky aurora
#

Cuz the graph hits pi again on the next shift

gloomy lance
#

So for tan(3x), the period is pi/3

plucky aurora
#

Pi over 3

#

Ok so

#

For

#

Would it be 2pie over 4

gloomy lance
#

No

#

You divide by the absolute value of the number that is multiplying x

#

tan(ax+b) has period pi/|a|

#

Also the period isn't affected if there's a number multiplying tanx

#

4tan(x-pi/4) has the same period as 3tan(x-pi/4)

plucky aurora
gloomy lance
#

You have some catching up to do man

#

The absolute value of a number x, denoted |x| is defined as
|x|=x, if x≥0
|x|=-x, if x<0

#

I.e. , it turns the number that you input positive

#

If its already positive it stays positive

#

|3|=3, |-3|=3

plucky aurora
#

Right

plucky aurora
gloomy lance
#

It's in the formula for the period of a tangent function of the form c*tan(ax+b)

#

Which is pi/|a|

plucky aurora
#

Can u show an ex

#

@gloomy lance

gloomy lance
#

tan(3-x) has a period of pi/|-1| = pi

#

8tan(2x-1) has a period of pi/|2|=pi/2

plucky aurora
#

Can u explain how

#

Thos arw the answers

plucky aurora
#

I dont rlly get that

gloomy lance
#

It's just the formula

#

You should've been taught that

#

Have you paid attention to class

#

The formula for the period of sin(ax) and cos(ax) is 2pi/|a|

#

for tan(ax) it's pi/|a|

violet lance
glossy valveBOT
#

r4f43l1006

violet lance
#

check it in desmos or smth

plucky aurora
violet lance
plucky aurora
#

Oo

plucky aurora
#

For p

#

And same with cot

violet lance
plucky aurora
#

Pi over |a|

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plucky aurora
#

Mnfok

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odd hill
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if they say
a ⊥ b ⊥ c
does that imply a ⊥ c
because A could be ⊥ to C
but
A could also be parallel
to C

wide sundial
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Well perp is not a transitive relation

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So they’re being ambiguous with it

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Where are you seeing this?

full forumBOT
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@odd hill Has your question been resolved?

odd hill
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.close

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torn jolt
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a bit of general question I have: could one visualise volumes of solids of revolution on desmos 3D?

torn jolt
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i lowkey think it would be fun to look at

umbral dome
torn jolt
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very cool, i should have looked there first

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sharp harbor
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sharp harbor
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Need help in the last question

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<@&286206848099549185>

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@sharp harbor Has your question been resolved?

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@sharp harbor Has your question been resolved?

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full forumBOT
full forumBOT
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@sturdy valve Has your question been resolved?

modest obsidian
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feels like something to do with vieta's formula

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uhhh for any polynomial like $(x-r_1)(x-r_2)(x-r_3)\dots (x-r_n)$ its coefficient are symmetric sums of roots

glossy valveBOT
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parabolicinsanity

modest obsidian
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i think...

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something like that

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so i think coeff of this would just be the sum of the roots... maybe i think

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now you do

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just brush up on vieta's formulas

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i guess

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ex : $(x-r_1)(x-r_2)(x-r_3)=x^3-(r_1+r_2+r_3)x^2+(r_1r_2+r_2r_3+r_3r_1)x-r_1r_2r_3$

glossy valveBOT
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parabolicinsanity

modest obsidian
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no, they're symmetric sums

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different things

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just look into this

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just keep in mind these are

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uhhh

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symmetric sums

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so symmetric sum notation

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weird that-

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you have a problem on that but don't know how to do it...

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😔 that's just vieta's formulae, brush up on it i guess and you'll be fine

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but do notice

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the first term is

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(r-x)

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so reverse it

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modest obsidian
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happy mathing splendid

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you just have to find it so

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there's a certain joy in being able to solve mathematical problems

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find it

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you'll never be able to stop after that

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modest obsidian
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😔 opened another channel but sure make it quick

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then close it

tacit siren
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Why does it have to be done in 3 minutes?test question?

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<@&268886789983436800>

austere cove
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No academic dishonesty

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.close

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modest obsidian
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weird...

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torn jolt
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I'm trying to answer part e iii. In the previous parts, I claimed that B and C were both not compact so I attempted to use Hausdorfness as a topological property to prove B is not homeomorphic to C. I claimed C is Hausdorff as for all distinct x,y in Z, we can take the open neighbourhoods U of x and V of y to be the balls of radius 1/2 centered at x and y respectively which are disjoint. Im now struggling to show B is not Hausdorff. Ive written the definition of Hausdorffness but wasnt sure what to do then. I'm also wondering if contradiction is the correct path for this. Any help would be appreciated!

rapid rain
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so the idea is that B has accumulation points but C doesn't, all points of C are isolated

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which is what you did

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To show B is hausdorff though

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B should be hausdorff shouldn't it?

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for any two distinct points x and y of B

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take B(x,delta) and B(y,delta) with delta = |x-y|/3 as neighborhoods of x and y respectively

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A metric space is always gonna be hausdorff

torn jolt
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Ah yeah good point. I forgot all metric spaces were Hausdorff haha. We've only covered the topological properties of Hausdorff, compactness and connectedness and since (I think) theyre both not compact, that only leaves Hausdorff and Connectednes and I'm fairly sure theyre both disconnected, so I'm not really sure how else to show they're not homeomorphic.

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Wait unless they are homeomorphic

rapid rain
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If B and C were homeomorphic, let f:B->C be a homeomorphism

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{0} is an open subset of C (why?)
thus {a} is an open subset of B for some a in B

torn jolt
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Is {0} an open subset of C as it has subspace toplogy and the interval say (-1/2,1/2) is open in standard topology so (-1/2,1/2) intersect C which is {0} is open in C?

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And then {a} cant be open in B as whenever we intersect B with an open subset of R, it will include irrationals which aren't in B or something?

rapid rain
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if you intersect B with an open subset of R

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by definition of B

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it's only gonna contain rationals

torn jolt
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Ah ofc haha

rapid rain
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the idea is indeed to look at what are the open subsets of B for its topology

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just imagine how many numbers are gonna be in open subsets of B

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imagine (a,b) intersected with B

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and get rid of cases where it's empty

torn jolt
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I see. Are there gonna be an infinite amount of points when (a,b) is intersected with B? Could this possibly have something to do with the closure of B being the whole interval [0,1] or something?

rapid rain
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B is dense in [0,1] (or the closure of B in R is [0,1])

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yeah

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so it's gonna coincide with every single open subset of [0,1]

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you can split an open subset into as many disjoint open subsets as you want (with some extra points here and there)

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there's an infinity of rational numbers between a and b

torn jolt
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Ah ok that makes sense!

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I think I understand whats going on now. Tysm!

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winter patio
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please

full forumBOT
winter patio
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like i juts cant with these natural logs

gritty rose
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take log of both sides

winter patio
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plesase can we like step by step

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im so frustrated w it

gritty rose
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,tex .log power

glossy valveBOT
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riemann

winter patio
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so

gritty rose
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what do you get after taking log of both sides

winter patio
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dont we have to use ln

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i thoughjt

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cus its e

gritty rose
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doesn't matter the base

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you pick either base 2 or base e

winter patio
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so log(x-3)=2log(x+2)

gritty rose
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no

winter patio
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log(e^x-3)

gritty rose
winter patio
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so e is the x right

gritty rose
winter patio
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is x-3 not y

gritty rose
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x-3 is in the exponent yes

winter patio
gritty rose
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you're missing parentheses

winter patio
gritty rose
winter patio
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its 2log(x+2)

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waity no

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(x+2)log2

gritty rose
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correct

winter patio
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i dont kniw what to do net

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like im extremel confuse

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d

gritty rose
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solve for x

winter patio
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does log e equal 1

gritty rose
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yes

winter patio
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i have

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(x-3)=(x+3)log2

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am i ssupposed to divide by log

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2

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oh my god

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girl can i have a new helper

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like i just cant

gritty rose
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wut

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why are you being dramatic

gritty rose
winter patio
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girl i asked u to guide me im iunsure on how to do the whole thing its just frustratingatm

gritty rose
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you're making progress

winter patio
gritty rose
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yes

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$a(b+c) = ab + ac$

glossy valveBOT
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riemann

sturdy valve
winter patio
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idk whats wrong w my brain todsy

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but it jusy doesnt wnt to understand for some resson

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i stil dont understand

gritty rose
winter patio
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so is it xLog2 +3log2

gritty rose
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correct

winter patio
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i literally have

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x-3=xLog2 +3log2

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.close

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glossy valveBOT
#

Dhairya

wispy lichen
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at alpha = 1 its zero so 0

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winter patio
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im back

full forumBOT
winter patio
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i know this is elementary

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ik how to do it but my teacher want it done w no calculator

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like how is tht possible

vestal moat
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How do you do it ? And Let’s see if you can figure out a way without a calculator.

winter patio
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cus

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i have

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2800(1+0.15)^4

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for part

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a

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i simplified it ot

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to

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2800(4.60)

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but thats def wrong

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yesa it is

wispy lichen
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maybe use the binomial

tender delta
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Do you know about compound interest

winter patio
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no i forgot it

winter patio
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Where yall went

wispy lichen
winter patio
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Girl

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I don’t think we need all this 😭

wispy lichen
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use the squared term

grave elm
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but it's 1.15^4 = 1.15 * 1.15 * 1.15 * 1.15

wispy lichen
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if its too small you can approx it to 1.60

grave elm
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i wouldnt wanna do that without calculator

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if i had to do it without calculator, 1.15 = 23 / 20 so i'd instead do that

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23 * 23 = 529, if we are allowed to approximate a bit, say it's 530

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530 * 530 = 280, 900

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now just divide that by 20^4 = 16 * 10^4

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28,09 / 16 (approximately 28 / 16 = 7 / 4 = 1.75)

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1.75

winter patio
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But isn’t that much like I don’t understand why he just doesn’t let us use a calculator

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He’s so evil

grave elm
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i honestly dont understand it either

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how much time do you have for this

winter patio
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It’s a review for my exam

grave elm
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will you have exam on your exam

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*calculators

winter patio
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Mo

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No

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Not allowed

grave elm
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how accurate does he require the stuff to be

winter patio
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Idk I asked him am I just supposed to leave it as a formula

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Waiting for his response