#help-13

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cedar kilnBOT
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crimson sedge
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for this question do u just draw a straight line by hand not using any points for ref

crimson sedge
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and would u just two points from that line u drew for part b ?

west stag
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just draw a tangent line

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prolly should label the coordinates

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of the point that is touching

cedar kilnBOT
#

@crimson sedge Has your question been resolved?

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shy pagoda
cedar kilnBOT
shy pagoda
#

$\frac{\partial F}{\partial y} = {\ln(x)}\frac{\partial f}{\partial y}$

wraith daggerBOT
shy pagoda
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$\frac{\partial F}{\partial x} = \frac{y}{x}\frac{\partial f}{\partial x}$

wraith daggerBOT
neon moon
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$f$ is a single function of one variable (let’s say it is "$t$"), so you don’t need to use the partial to denote its derivatives. 🙂

wraith daggerBOT
#

jimmy1234

shy pagoda
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so LHS should be ${y}\frac{\partial f}{\partial x} + {y}{\ln(x)}\frac{\partial f}{\partial y}$

wraith daggerBOT
shy pagoda
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so LHS is ${y}\frac{df}{dx} + {y}{\ln(x)}\frac{df}{dy}$

wraith daggerBOT
shy pagoda
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i think at least

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$\frac{\partial^2 F}{{\partial x}{\partial y}} = \frac{1}{x}\frac{df}{dx} + \frac{y}{x}\frac{d^2 f}{{dx}{dy}}$

wraith daggerBOT
shy pagoda
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this is where i expect ive got something wrong

neon moon
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What i mean by "no partial" is that, there are no separate "dx" or "dy" for f.

There is just a single "dt" for f(t) as a function of a single variable t.

shy pagoda
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oh

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so i should let t = y * ln(x) and then deal with derivatives of f with respect to t?

neon moon
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Let $t = y \ln x$, then $\frac{\partial F}{\partial x} = \frac{df}{dt} \frac{\partial t}{\partial x}$

wraith daggerBOT
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jimmy1234

shy pagoda
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ok

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that makes sense

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so $\frac{\partial F}{\partial x} = \frac{y}{x}\frac{df}{dt}$ and $\frac{\partial F}{\partial y} = {\ln(x)}\frac{df}{dt}$

wraith daggerBOT
cedar kilnBOT
#

@shy pagoda Has your question been resolved?

shy pagoda
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sorted

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.close

cedar kilnBOT
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weak mountain
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What's the general idea to show that a space is not hausdorff?

weak mountain
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Show that for every neighborhood around a point x, y must be in it?

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(open nbh)

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Trying to show this for the co-countable topology on an uncountable set X

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nvm i was dumb

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.close

cedar kilnBOT
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deep patrol
cedar kilnBOT
deep patrol
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Hello

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So i looked at this answer key and started wondering

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So if you look at the bottom right

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There are two answers

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And they are answers in which they repeat every 180 degrees

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But how about we put them into just one answer

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And repeat every 90 degrees instead?

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Like, starting from 30

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So

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Pi/6+k*pi/2

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How about this?

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Would this still be the same as the bottom right of the image?

karmic cedar
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The difference between the two is 2pi/3

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120 deg

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You would get 120 degrees instead of 5pi/6(150)

deep patrol
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Ooh

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Nvm

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I thought both of them together would be every 90

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But i was wrongp

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Wrong

karmic cedar
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Yeah that happens

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Radians r hard

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For me at least

deep patrol
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Yeah

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They are not all the same

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Angles

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Only two of them are

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Alright i solved the problem

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All done

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Much appreciated

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@karmic cedar

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.close

cedar kilnBOT
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drifting solar
cedar kilnBOT
drifting solar
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Can someone double check me on this?

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my work is sending lol

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Honestly just trying to make sure my bounds are correct, the actual setting up the integral s where I think I make the most mistakes

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@ me when someone gets this pls

cedar kilnBOT
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@drifting solar Has your question been resolved?

cedar kilnBOT
#

@drifting solar Has your question been resolved?

hoary spoke
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I have a question

small dust
hoary spoke
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How many 3 digit numbers exist such that their first digit equals to the Sum of of other two

hoary spoke
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I edited it

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There was a mistake

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Oh....o

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Is this occupied?

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Sorry then

drifting solar
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All good

cedar kilnBOT
#

@drifting solar Has your question been resolved?

cedar kilnBOT
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crimson sedge
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you’ve picked 3 cards out that arent hearts

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how many cards are there, how many are hearts?

grave radish
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then thered be 39 cards left

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13 would be hearts

crimson sedge
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not 39

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but yeah

grave radish
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wait sorry why wouldnt it be 39

heavy sorrel
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bcoz u have already taken out 3 non heart cards

grave radish
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oh right

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then would it be like

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P(heart on fourth draw | first three not hearts) = (39/52) * (38/51) * (37/50) * (13/49) / (39/52) * (38/51) * (37/50) = 13/49

cedar kilnBOT
#

@grave radish Has your question been resolved?

grave radish
#

<@&286206848099549185>

fair geyser
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sure

grave radish
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so it'd be 13/49 and not 13/52 right

fair geyser
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yeah

grave radish
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okok thank u

grave radish
#

.close

cedar kilnBOT
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cobalt wyvern
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How can I solve for ii and iii

cedar kilnBOT
cobalt wyvern
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I did i and got -8 + 8 * root(3)

cedar kilnBOT
#

@cobalt wyvern Has your question been resolved?

cobalt wyvern
#

<@&286206848099549185>

lethal jackal
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what's the square root of $e^9$?

wraith daggerBOT
#

Saccharine

cedar kilnBOT
#

@cobalt wyvern Has your question been resolved?

gritty galleon
cedar kilnBOT
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coral vortex
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hey can i get some help please

cedar kilnBOT
coral vortex
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can you help with IB AA HL?

lethal jackal
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maybe

coral vortex
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its just some section A questions

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this is the question

gritty galleon
coral vortex
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yes

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i dont understand how on earth to do ti

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it

gritty galleon
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ah'

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lemme see

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Okay

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Let f(x) = pix^2

coral vortex
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okkkk

gritty galleon
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Now, Can you rewrite the expression for V in terms of the function f(x)?

cedar kilnBOT
#

@coral vortex Has your question been resolved?

cedar kilnBOT
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covert island
cedar kilnBOT
covert island
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when i solve using fraction decomp

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i kind of get stuck on a value

lunar plaza
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have you tried integration by parts

covert island
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uhhhh

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isnt fraction decomposition

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integration by parts

lunar plaza
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my bad

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i didnt know4HEad

covert island
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if i break it up you get

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A(y+2)(y+3) + B(y)(y+3)+ C(y+2)y

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2 of the values overlap and can cancel to 0

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so B = 5 and C = -45

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but i cant figure out A

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wait

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im dumb

lunar plaza
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wait wa

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wont you get ln

covert island
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i figured it out

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i think

lunar plaza
#

try using partial fraction

covert island
#

.close

cedar kilnBOT
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elfin otter
#

Anyone know how to do this with basic trigo? (meaning no sine/cosine rule)

lunar plaza
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can you take a better picutre please

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a closer one

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are you malaysian btw

gritty galleon
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A translation would be really helpful

lunar plaza
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theres english at the bottom too

elfin otter
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Ye

gritty galleon
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OH

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sorry 😅

elfin otter
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,rotate

wraith daggerBOT
gritty galleon
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Isnt that just the circumference of thec circle? OH NO OFC NOT

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nthing

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Do you know tangents drawn to circle from the same point theorem?

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It means PS = PQ

lunar plaza
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soq

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should be double of 53

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and minus

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360

elfin otter
# wraith dagger
Find
1) x
2) length of SU
3) perimeter of shaded region
4) area of shaded region
olive lance
#

sorry, which ones do you not know?

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and what have you tried so far

lunar plaza
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x should be 127

elfin otter
gritty galleon
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@lunar plaza first explain

lunar plaza
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because ps pq

elfin otter
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This is can do AM but cannot do normal Maths syndrome

lunar plaza
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is tangent

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and soq is inside of the circle

olive lance
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so here's a couple of useful facts

lunar plaza
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so by taking 53 times 2

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you will get the soq smaller angle 106

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and 360 minutes 106 will give you the bigger angle

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and the big angle is 254

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and finding x

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you just have to simply divide it by 2

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and it iwll get you 127

elfin otter
limber bay
#

Hi, I wanna know if I did the question right, q7

olive lance
lunar plaza
elfin otter
#

Gonna do it from here but will come back if I blank out again

olive lance
#

just to be clear

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i think zong is wrong here

lunar plaza
#

wa

olive lance
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x is acute here

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it cant be 127

lunar plaza
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true

olive lance
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i think the mistake you make is that angle SOQ is 53*2

lunar plaza
#

im sorry

olive lance
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i dont think that is the case

lunar plaza
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and the point p isnt in the circle too

olive lance
lunar plaza
#

but does 116.5 make sense

olive lance
#

for what?

lunar plaza
#

the angle x

olive lance
#

it should be less than 90 degrees

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there's a right angle in the triangle

lunar plaza
#

@elfin otter you are not leaving until you tell me the answer

lunar plaza
olive lance
#

so like i said, here's a couple of useful facts and a hint:

  • if a radius is perpendicular to a chord, then it bisects it.
  • You already know this but it's important to restate, OQ, and OW are both radii, so you know their lengths.
  • ||The quad PQOS is cyclic, do you see why?||
lunar plaza
#

because all points is touching the edge ?

gritty galleon
#

OS = 2r - 2, I just realized

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and the chords gon be half like Shell said

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So that gives you the sides

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OY = r-2

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You have all the sides

lunar plaza
gritty galleon
#

Do inverse ratio (asin / acos / atan)

olive lance
gritty galleon
olive lance
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so you get the QOS angle, yes

lunar plaza
#

this is holding me back no asin acos

elfin otter
olive lance
#

SW = SY + YW

elfin otter
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Yes

olive lance
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whats SW?

elfin otter
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10

olive lance
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and YW?

elfin otter
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2

lunar plaza
#

shell are you good at alevel mechanics do you mind helping

gritty galleon
olive lance
elfin otter
#

8

olive lance
#

thats what they were saying

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because r = 5

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let me put things this way

elfin otter
olive lance
#

if you want x, you need SY and UY

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SY can be gotten this way

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UY is not so simple

olive lance
#

i also recommend working backwards

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if you want UY, what are the different ways of getting UY?

elfin otter
olive lance
#

thats just fancy terminology

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let me put it this way

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what is the sum of all angles of a quad?

elfin otter
elfin otter
olive lance
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and you know one of the angles, QPS right?

elfin otter
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Ye

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53

olive lance
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but what are PQO and PSO (angles)?

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given that PQ and PS are tangents

gritty galleon
elfin otter
olive lance
#

let them think abt it

olive lance
elfin otter
#

Opposite sides + tgt = 180 ?

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For QOS

olive lance
#

wdym

elfin otter
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My angle for QOS would be 180-53

olive lance
#

ah

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yes

elfin otter
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180-53) /2

olive lance
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why /2?

elfin otter
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For PQO n PSO

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Oh no

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Fk

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Dumb

gritty galleon
olive lance
#

nah

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again, remember that PQ and PS are tangents

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and that OQ, OS are radii

gritty galleon
#

SOQ is 127..?

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the obtuse one

elfin otter
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Ye

gritty galleon
#

and the inside one is 233

olive lance
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just to be clear

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the angles PQO and PSO are both 90 degrees

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do you see that?

elfin otter
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Ah.

gritty galleon
#

Cus tangent-from-same-point-radius theorem thing right?

elfin otter
#

Yes

olive lance
#

so now that you have that

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its just that

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90 + 90 + QOS + 53 = 360

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and you get the angle from there

elfin otter
#

Aight I think I got it

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Can't afford to be this brain dead tmr...

olive lance
#

relatable

gritty galleon
# wraith dagger

Well with SOQ, what next? YOQ is 233 - some quantity, but what?

elfin otter
olive lance
#

good luck!

gritty galleon
elfin otter
#

N with ur spirit

#

Thanks guys 🫂

#

.close

cedar kilnBOT
#
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reef lynx
#

Hi I know this is a math server but I was wondering if anyone could help still, I'm sort of unfamiliar with this type of circuit, mainly the circle with the arrow in it and the resistance that has a current. The question asks to find the value of the Current and Voltage on R3

lusty grotto
#

Circle with an arrow is a current source

reef lynx
#

do you know how to solve for r3?

lethal jackal
#

nodal analysis is your friend

reef lynx
#

elaborate please

lethal jackal
#

In electric circuits analysis, nodal analysis, node-voltage analysis, or the branch current method is a method of determining the voltage (potential difference) between "nodes" (points where elements or branches connect) in an electrical circuit in terms of the branch currents.
In analyzing a circuit using Kirchhoff's circuit laws, one can eithe...

reef lynx
#

could you help me implement it?

cedar kilnBOT
#

@reef lynx Has your question been resolved?

reef lynx
#

@lethal jackal

cedar kilnBOT
#

@reef lynx Has your question been resolved?

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cedar kilnBOT
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tough karma
cedar kilnBOT
tough karma
#

I don't understand how they used tan(X/2)= u to write cos

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This is what I've reached at

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I understand the partial fractions part

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<@&286206848099549185>

ancient lodge
tough karma
#

Oh

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Alright thank you

#

.close

cedar kilnBOT
#
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cedar kilnBOT
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stark bronze
#

[\frac{30(4x-3)^{2}}{(2x+1)^2} * \frac{1}{(4x-3)^{2}}]
[\frac{30(4x-3)^{2}}{(2x+1)^4}]

wraith daggerBOT
#

dopediscorduser

stark bronze
#

How does this first step equal the second?

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I don't understand how you can just add the exponents of the denominators when they're two different terms?

tranquil oracle
#

yeah i don't think it is

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perhaps there's further context?

stark bronze
#

This is the question

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I solved by using the extended power rule, k(g(x))^k-1 * g'(x)
Using the product rule on the derivative g'(x)
And then simplifying the result

tranquil oracle
#

yeah i don't see where you get that step

stark bronze
#

Give me a sec and I'll type out my work

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[-3(\frac{2x+1}{4x-3})^-2 * \frac{d}{dx}(\frac{2x+1}{4x-3})^2 \text{ Extended power} ]
[-3(\frac{2x+1}{4x-3})^-2 * \frac{-10}{(4x-3)^2} \text{ Product}]
[30(\frac{2x+1}{4x-3})^-2 * \frac{1}{(4x-3)^{2}}]
[\frac{30(4x-3)^{2}}{(2x+1)^2} * \frac{1}{(4x-3)^{2}}]
[\frac{30(4x-3)^{2}}{(2x+1)^4}]

wraith daggerBOT
#

dopediscorduser

stark bronze
tranquil oracle
#

you need to $a^{-2}$

wraith daggerBOT
#

Element118

tranquil oracle
#

not sure what you mean by extended power, but shouldn't the exponent decrease? @stark bronze

stark bronze
#

[-3(\frac{2x+1}{4x-3})^{-4} * \frac{d}{dx}(\frac{2x+1}{4x-3})^2]

wraith daggerBOT
#

dopediscorduser

stark bronze
#

Like this?

tranquil oracle
#

yeah that seems to be it that part's fixed but not yet

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but i'm not sure why your d/dx

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you should get this?
$-3\left(\frac{2x+1}{4x-3}\right)^{-4}\times\frac{d}{dx}\frac{2x+1}{4x-3}$

wraith daggerBOT
#

Element118

tranquil oracle
#

@stark bronze not sure why there's the squared for the part you differentiate

stark bronze
#

I didn't mean for that to be there

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Sorry my latex is really a mess

cinder venture
#

@stark bronze

cinder venture
#

What’s the situation

stark bronze
#

I know the answer is right

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I just don't understand why

cinder venture
#

For what part

stark bronze
#

Give me just a sec

#

I'm typing something out in latex

cinder venture
#

Okay

stark bronze
cinder venture
#

I didn’t use the method you used but would you like to see it? Or you have to use the extended power thing

stark bronze
#

I'm typing my work out rn

cinder venture
#

The working

stark bronze
# wraith dagger **Element118**

[-3\left(\frac{2x+1}{4x-3}\right)^{-4}\times\frac{d}{dx}\frac{2x+1}{4x-3}]
[-3\left(\frac{2x+1}{4x-3}\right)^{-4}\times\frac{-10}{(4x-3)^{2}}]
[\frac{30(2x+1)^{-4}}{(4x-3)^{-4}} \times \frac{1}{(4x-3)^2}]
[\frac{30(2x+1)^{-4}}{(4x-3)^{-2}}]
[\frac{30(4x-3)^{2}}{(2x+1)^{4}}]

wraith daggerBOT
#

dopediscorduser

stark bronze
#

Does this look correct?

stark bronze
cinder venture
stark bronze
cinder venture
#

Yes

#

Well wait

stark bronze
#

Where am I going wrong?

cinder venture
#

No issue

stark bronze
#

Awesome

#

Thanks for the help!

cinder venture
#

No problem

stark bronze
#

.close

cedar kilnBOT
#
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supple forge
#

I really need help with this question asap and I don't know the basics either cause I wasn't well and I didn't attend the lectures. My friends are no help either. pls help 😦

sullen saffron
supple forge
#

well beacuse the prof wants the submission by 12am IST. and i have like 2

#

2.15 hrs

sullen saffron
#

We don't give out answers and you said you don't know the basics so I'm not sure the server can be much help for you.

supple forge
#

oh okayy. thanks then

#

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elder kestrel
cedar kilnBOT
elder kestrel
#

does the modulus of derivative equal the derivative of modulus?

crimson delta
#

general advice, dont upload random files

#

also no, chain rule and lets not ignore that absolute values are not differentiable everywhere

south tundra
#

Yup, consider the modulus of the derivative of x at 0 and the derivative of the modulus of x at 0

cedar kilnBOT
#

@elder kestrel Has your question been resolved?

cedar kilnBOT
#

@elder kestrel Has your question been resolved?

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crimson sedge
cedar kilnBOT
crimson sedge
#

How can I add these two together

#

Then being in a fraction form is throwing me off

sage forge
#

First try to cancel the two in the left denominator

crimson sedge
#

I don’t follow?

#

So the left side jsut divide it ?

sage forge
#

OK, it might be faster if we do it in a different order

#

For the right side of the + you can use that sqrt(a/b) = sqrt(a)/sqrt(b)

#

Can you try to apply it?

crimson sedge
#

Uh

wraith daggerBOT
#

Stephen

sage forge
crimson sedge
#

@sage forge

sage forge
#

,rotate

wraith daggerBOT
sage forge
crimson sedge
#

I was just pinging u so u could see that I applied it lol

sage forge
#

Yeah

crimson sedge
#

What would my next step Be? @sage forge

sage forge
#

Can you simplify sqrt (112)?

crimson sedge
#

Yea into 16 x rt 7

#

So it would just be 28

#

4 x 7 = 28

sage forge
#

Why 16 sqrt(7)? It is sqrt(16*7), which is sqrt(16)*sqrt (7)

#

OK?

crimson sedge
#

Oh yea

#

But then it would 4sqrt7 tho right

sage forge
#

Yes

#

Can you do the same for sqrt (28)?

crimson sedge
#

4 sqrt 7

#

Sqrt 4 sqrt 7

#

Then 2 sqrt 7

sage forge
#

Very good

#

Now to the sqrt(x^2)

#

Do you have an idea how to simplify this?

crimson sedge
#

Uh

#

No

sage forge
#

sqrt(x^2) = |x|

#

Okay?

crimson sedge
#

Uh

#

I get the x part

#

Not the abs values part

sage forge
#

Because sqrt ((-4)^2) = sqrt(16) = 4

#

sqrt does always give you the positive solution to the equation x^2 = a

#

Did it become clearer?

crimson sedge
#

Yes

sage forge
#

OK, now we can say that |x| = sign(x) *x. Sign of x is defined as 1, if x is positive and -1 if it is negative. So this is basically a fancy way of writing +- x

#

Okay?

crimson sedge
#

Ok thank you for ur time

#

.close

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#
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harsh rover
#

i have no clue how to go about this so someone please help/hint

cedar kilnBOT
#

Please don't occupy multiple help channels.

harsh rover
#

sorry

#

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brittle field
cedar kilnBOT
brittle field
#

sqrt 9-40x becomes (9-40x)^1/2 ? and thats my f

#

how do i find g?

red pumice
#

$\sqrt{9-40x} = (9 - 40x)^{\frac{1}{2}}$ by definition

wraith daggerBOT
red pumice
#

what do you mean by find f and g?

#

do you mean for the chain rule

brittle field
#

yes

red pumice
#

9-40x should be one of your functions

#

and sqrt(x) the other

#

such that f(g(x)) = sqrt(9-40x)

brittle field
#

wont it be ((9-40x)^1/2)(g(x)) ?

red pumice
#

your function is (9-40x)^(1/2)

#

which you want to differentiate

#

using the chain rule

brittle field
#

but chain rule needs f and g right?

red pumice
#

yeh

red pumice
brittle field
#

and i multiply that with g ? what will g be?

red pumice
#

$\dv{x} f(g(x)) = f'(g(x))g'(x)$

wraith daggerBOT
brittle field
#

yes, so its 9x-40(g(x))

red pumice
#

no

brittle field
#

oh, do you know how it should be?

red pumice
brittle field
#

so i need f and g right

red pumice
#

yes

brittle field
#

how would i get g

red pumice
#

did you get f?

brittle field
#

yes you said its 9x-40 right?

red pumice
#

choosing g(x) = 9 - 40x makes more sense

red pumice
brittle field
#

ok so f(9x-40)

red pumice
#

should be equal to ...

brittle field
#

f'(9-40x) * g'(9-40x)

red pumice
#

no

#

you need to do the first part

#

find f(x) and g(x) such that f(g(x)) = sqrt(9 - 40x)

brittle field
#

how would i do that

brittle field
#

.close

cedar kilnBOT
#
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wary anchor
cedar kilnBOT
wary anchor
#

answer for question 6)a) is wrong right?

#

beucase its cos(x) should it be 360-ans then ±360

tardy storm
#

hmm, let me try help

#

so, i should give only one solution to number 6? @wary anchor

wary anchor
#

well

#

in the interval -180< x <180

cedar kilnBOT
#

@wary anchor Has your question been resolved?

tardy storm
#

no :(

#

kinda busy tbh

#

do it yourself :) the hard way

wary anchor
#

<@&286206848099549185> anyone else?

crimson sedge
wary anchor
wary anchor
#

and also +_ 18.4

crimson sedge
#

Solved here, but I didn´t understand your question exactly

#

For me it fits also for 161,6 degrees

nimble veldt
wary anchor
#

i got -9.488

#

wait

crimson sedge
wary anchor
#

i got 9

#

yeh

crimson sedge
#

9.00365

nimble veldt
crimson sedge
#

haha

wary anchor
#

but what about the intervals

#

because how i was taught, you do arccos(answer) to get one angle

#

then you do 360- answer to get the next

#

eg

#

arccos(x) = 18.4

#

360-18.4 =341.6

#

then 341.6-360 = -18.4

crimson sedge
#

it´s +_ sqrt 9/10

#

you have to check for both signals

wary anchor
#

ahh

#

thats where i done wrong

#

well

#

not complete

#

actually makes sense now

crimson sedge
#

Indeed!

wary anchor
#

Thanks

#

💀 1 hour for 1 question

nimble veldt
nimble veldt
crimson sedge
#

so if for instance he gets 193,4 degrees it'll not be accepted as an answer for this particular question.

nimble veldt
#

maybe its a commnly used method. but usesless in such cases of examples. if i have a solutionx in [0,180], why should someone calc 360-x which leads to another solution outside the accepted intervall?

crimson sedge
#

But yeah, in some intervals it's completely useless

native sapphire
nimble veldt
#

@native sapphire get your own channel.

wary anchor
#

.close

cedar kilnBOT
#
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cedar kilnBOT
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proven kelp
cedar kilnBOT
crimson sedge
#

this is I guess Physics

proven kelp
#

any idea on how to solve?

cedar kilnBOT
#

@proven kelp Has your question been resolved?

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torpid urchin
cedar kilnBOT
torpid urchin
#

my prof said that this question is solvable through partial fractions, as it is an implicit function so we cant go about finding a solution normally. could anyone help me out with how to do this via partial fractions?

#

sort of confused on where to pull fractions from and quite honestly where to start lol

cosmic steppe
#

Wdym implicit function

torpid urchin
#

like

cosmic steppe
#

I'm pretty sure your primitive is gonna be an equation not a function

torpid urchin
#

y+e^y

#

cannot isolate for y here

cosmic steppe
#

It's fine as is

#

It's an implicit equation

torpid urchin
#

right

#

weve never done these before

#

so i am confused as to where to go

cosmic steppe
#

Yeah no that's fine

#

What you have should work

torpid urchin
#

ok

#

so to isolate for y i was thinking implicit differentiation or something but im not sure that provides anything?

cosmic steppe
#

although

#

Hm

#

Well the equation is symmetric along y=x

#

Lemme graph it

#

Because the thing is the relationship for y is the exact same for x

#

Like if I let p(n) = n + e^n

#

p(x) = p(y)

torpid urchin
#

right

cosmic steppe
#

Lemme graph this

#

I'm thinking it simplifies down to y = x

torpid urchin
#

but supposedly partial fractions have to make an appearance here

#

but im not sure where that would be relevant

cosmic steppe
#

Yeah same, I'm just using analysis

#

Turns out I was right

#

p(y) = p(x) implies a linear relationship

torpid urchin
#

yeah it logically makes sense there

#

y=x

#

but why would i ever need partial fractions 😭

cosmic steppe
#

No idea

torpid urchin
#

so without this analysis

#

is there a way to go about isolating for y

cosmic steppe
#

Lambert W

torpid urchin
#

ok so not something weve learned

#

is this what youre referring to O_O

cosmic steppe
#

No

#

Well yeah

#

That's the

#

Uh

#

Shit I'm blanking

#

But yes that's Lambert W visualized in a weird way

#

Forgor the word 💀 but yeah

torpid urchin
#

woah it has a real and imaginary plane

#

ok yeah

#

definetly not something weve covered

cosmic steppe
#

But lemme ask if

cosmic steppe
torpid urchin
#

then y=x 🤩

#

im just stuck on the fact he mentioned partial fractions

#

could it have to do with manipulating the integrands before i even integrate so the implicit stuff doesnt appear?

cosmic steppe
#

Possibly

#

I'm gonna figure out something hold on

#

Hopefully in time because I do have to go soon

torpid urchin
#

no problem

#

symbolab is mentioning lambert w as well

cosmic steppe
#

Apparently p(x) = p(y) works because p(n) is injective

#

Which means the function is "one-to-one"

#

1 + e^n is one-to-one because e^n is monotonically increasing

#

So that's the analysis side of things lol

cedar kilnBOT
#

@torpid urchin Has your question been resolved?

torpid urchin
#

appreciate the help

royal loom
#

$$ y+e^y=x+e^x $$only when $$ y=x $$ $$ y+e^y=x+e^x \implies y-x+e^y-e^x=0 \implies 1(y-x)+1(e^y-e^x)=0 \implies y=x or y-x=e^y-e^x \implies y=x $$ again

wraith daggerBOT
#

AustinU

torpid urchin
#

right

#

so no need for partial fractions?

#

or even possible application

royal loom
#

I am hesitant to say for sure either way

torpid urchin
#

i personally cant see a use for them

#

but i understand this question from that perspective

#

just not how to use partial fractions

#

im going to shoot my prof an email for how he did this but thankfully i can get the answer to this for now

#

thanks

#

.close

cedar kilnBOT
#
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wide cove
cedar kilnBOT
wide cove
#

I need help finishing this trig substitution. I don't know if I started this right

#

And then I just need anyone to help me walk through this problem

shut panther
#

,rcw

wraith daggerBOT
cedar kilnBOT
#

@wide cove Has your question been resolved?

wide cove
#

<@&286206848099549185>

wide cove
#

.close

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humble sleet
#

Hello

cedar kilnBOT
humble sleet
#

is it possible to verify a solution set to an inequality

#

inequation

cedar kilnBOT
#

@humble sleet Has your question been resolved?

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hollow rock
#

I think the answer should be (729/8000)/(504/6840), but its not right

hollow rock
#

man i got a goofy ah question compared to everyone else's help

cedar kilnBOT
#

@hollow rock Has your question been resolved?

hollow rock
#

<@&286206848099549185>

#

.close

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bronze briar
#

I need to find gcd(100, -35) and write it in the form of ax + by, where x,y are integers. Im not really so sure what to do

cedar kilnBOT
#

Please don't occupy multiple help channels.

bronze briar
#

i know that the gcd is 5

#

sorry, just closed the other channel. forgot about that one

#

or do i just divide both numbers by 5 and say that it's -7x + 20y?

#

<@&286206848099549185>

devout galleon
#

can you show us the text of the problem?

bronze briar
#

yeah sorry:

devout galleon
#

if gcd(100, -35) = 5 then x = -1, y = -3 and you can write -100x+35y = -100 + 3*35 = -100 + 105 = 5, etc.

bronze briar
#

im so confused. Where did you gegt x = -1, and y = -3? Also where does the number 5 play a role in the equation?

devout galleon
#

your question in other words: for every pair of a and b, find x, y pairs that stisfyies this equation gcd(a, b) = ax + by

#

x, y in Z

devout galleon
#

check it )

#

you see

bronze briar
#

so the linear combination should add up to 5, right?

devout galleon
#

yeah, (should up to gcd(a, b) )

bronze briar
#

i mean, when x is 2 and y is 5 it works out

#

20(2) - 7(5) = 5

devout galleon
#

hey no

#

in the 23) a = 100, b = -35 and you calculated gcd(a, b) = gcd(100, -35) = 5.

devout galleon
#

then you neet to solve this ax+by=gcd(a, b)

#

100x-35y=5

bronze briar
#

ohh so that's it?

#

i apologize for my extreme stupidity lol

#

that was so obvious

devout galleon
#

yes

bronze briar
#

thank you, i appreciate it!

#

.close

cedar kilnBOT
#
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crimson sedge
#

I don't understand

cedar kilnBOT
crimson sedge
#

Why when taking the x out of the sqrt

#

The sqrt becomes - sqrt

#

wtf

fervent locust
#

Oh

#

Mb

crimson sedge
#

/help

wooden quarryBOT
#

SlashCommand Did you know Beemo supports Slash Commands? They are the new, recommended way to discover and run commands! Type / to see them all.

crimson sedge
#

help

#

😦

#

<@&286206848099549185>

crimson sedge
#

Why does the sqrt turn negative?

#

Wdym

#

Im in my second semester of uni

#

Nice troll

#

<@&268886789983436800>

crimson sedge
cedar kilnBOT
#

@crimson sedge Has your question been resolved?

devout galleon
cedar kilnBOT
#

@crimson sedge Has your question been resolved?

harsh pelican
#

and how u coulf factor out x from thsi expression

cedar kilnBOT
#
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dusk finch
#

I have diff. eq. $\frac{d^{2}s}{dt^{2}}=\frac{1}{s^{2}}\\$
Assuming that $v=\frac{ds}{dt}\\\$
It can be said that $\frac{d^{2}s}{dt^{2}}=\frac{dv}{dt}=\frac{dv}{ds}\cdot\frac{ds}{dt}=\frac{dv}{ds}v\\\$
Therefore $v\cdot\frac{dv}{ds}=\frac{1}{s^{2}}$ and $v\cdot dv=\frac{1}{s^{2}}ds\\\$
So $\int v\cdot dv=\int \frac{1}{s^{2}}ds$ ‏‏‎ and $\frac{v^{2}}{2}=-\frac{1}{s}\\\$
Substituting for v $\left(\frac{ds}{dt}\right)^{2}=-\frac{2}{s}\\\$
Therefore $\frac{dt}{ds}=\left(-\frac{2}{s}\right)^{-\frac{1}{2}}$ and $\int dt=\int \left(-\frac{2}{s}\right)^{-\frac{1}{2}}ds\\\$
Evaluating $t=\frac{\sqrt{2}s}{3\sqrt{-s^{-1}}}\\\$
Solving for s $s=-\sqrt[3]{\frac{9t^{2}}{2}}$

dusk finch
#

Except for forgeting conditions and +C, what's wrong here?

wraith daggerBOT
#

MathIsAlwaysRight

dusk finch
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I mean even tho I forget conditions, the second derivative of the expression should be 1/s^2

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but it's not

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No way

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it actually works

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there are more solutions than 1

long swan
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why would the second derivative be 1/s^2

dusk finch
long swan
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keep track of what is your dependent and independent variable

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so i mean yes it would be 1/s^2 where s = what you got on the final line

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but maintain that distinction

dusk finch
long swan
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let's try verifying:

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,w d^2/dt^2 -cbrt(9t^2/2)

wraith daggerBOT
dusk finch
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,w 1/(-cbrt(9t^2/2))^2

wraith daggerBOT
long swan
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that negative sign!!!

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,w int (-2/s)^(-1/2) ds

wraith daggerBOT
dusk finch
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That means that s is always negative?

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Does this have multiple solutions or have I done something incorrectly?

cedar kilnBOT
#

@dusk finch Has your question been resolved?

cedar kilnBOT
#
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cedar kilnBOT
#
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hoary spoke
#

I have a q

cedar kilnBOT
hoary spoke
#

If 7k+5 is divisible by 9

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And k is natural

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What does it tell about k?

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What all can k be?

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I am certain that k cannot be a multiple of 9

cedar kilnBOT
#

@hoary spoke Has your question been resolved?

hoary spoke
#

No

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Fine I have another one

fair geyser
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i think it tells us that k+2 is divisible by 9

hoary spoke
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hm....

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How?

fair geyser
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somehow

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i got it by looking at all k

hoary spoke
#

hm....

hoary spoke
fair geyser
#

7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 : multiples of 7
7 5 3 1 8 6 4 2 0 7 5 3 1 8 6 4 : multiples of 7 mod 9
↑ ↑the fours
so k = 7, k = 16 are the first two solutions

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and it holds forever

hoary spoke
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Sorry but I don't know mod operations

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Can u tell me what does multiple of 7 mod 9 mean?

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Isn't 7 mod 9, 2?

fair geyser
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the first line is the multiples of 7

hoary spoke
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Yup

fair geyser
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the second line is the first line

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mod 9

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7 mod 9 is 7

hoary spoke
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You mean remainder after dividing by 9?

fair geyser
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yes

hoary spoke
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Oh

fair geyser
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every time it is 4

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it will become divisible once you add 5

hoary spoke
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Wow

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That's interesting

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And also amazing

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hm....

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So I have to find all the numbers where I got 4 after mod 9

fair geyser
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now there' must be a clever way to do it too, but i don't know it, this was caveman math

hoary spoke
#

Okay....

hoary spoke
fair geyser
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hm

hoary spoke
#

And don't get distracted by the 5 in the last line

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It is irrelevant

fair geyser
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well divisibility by 36 is divisibility by 4 and 9

hoary spoke
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Yup

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I deduced that the last number should be 2 or 7

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Sorry

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I mean 2 or 6

fair geyser
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no problem

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i'm stuck at this point

hoary spoke
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hmm ..

cedar kilnBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

hoary spoke
#

I am not done yet

fair geyser
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.reopen

cedar kilnBOT
#

fair geyser
#

it would understand if you clicked the ❌ back then, no problem

hoary spoke
#

Oh okay

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I have never used discord 😅

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I just had this account

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Anyone?

fair geyser
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oh wait, 5 is given

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i didn't notice

hoary spoke
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Ya

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3rd digit

hoary spoke
fair geyser
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well we can bruteforce that too then

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if it ends in 52, the first 2 digits must add up to 2 or 11

hoary spoke
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what

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😮🤔

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wdym?

fair geyser
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the trick for divisibility by 9 is that digits added up are divisible by 9

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so 2 + 7 or 11+ 7

hoary spoke
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Sorry i am confused

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Why ?

fair geyser
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i don't know, it's a trick

hoary spoke
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Really?

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Give me an example please

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Well I can see for 2 digits tho

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0+9

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1+8

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2+7

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3+6

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4+5

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And so on...

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But I am not sure for 3 or 4 digits

fair geyser
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,calc 351/9

wraith daggerBOT
#

Result:

39
fair geyser
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,calc 2358/9

wraith daggerBOT
#

Result:

262
fair geyser
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,calc 90909/9

wraith daggerBOT
#

Result:

10101
hoary spoke
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hmm.....

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So you mean that sum of all digits of multiple of 9 are also multiplies of 9?

fair geyser
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yes

hoary spoke
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Wtf

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When did that happen

fair geyser
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probably more than 800 years

hoary spoke
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💀

fair geyser
#

many number theory results are ancient history

hoary spoke
#

Do we have proofs for these?

fair geyser
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uh you can probably see it let me think

hoary spoke
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Okay

fair geyser
#

2358 = 2×1000 + 3×100 +5×10 +8
= 2×999 + 2 + 3 × 99 +3 + 5×9 +5 +8

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so those parts are divisible by 9 by themselves,
2×999 and 5×9 etc.
we can ignore them, they don't affect the divisibility of the sum

hoary spoke
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Isn't 2358 not divisible by 9?

fair geyser
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it's divisible by 9

hoary spoke
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Oh it is

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Sorry my bad

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hm...

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Now I got it.

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The proof

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For the sum of digits of multiple of 9 must also divisible by 9

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Thank you

fair geyser
#

okay

hoary spoke
fair geyser
#

as you said, there are 2 cases, it's __52 or __56

hoary spoke
#

Yes....

fair geyser
#

if it's 52, the first digits must add up to 2 or 11

hoary spoke
#

hm...

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Ph

fair geyser
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then the entire sum will be 9 or 18

hoary spoke
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*oh

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So that the sum is multiple of 9!

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I mean 9

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Not factorial

fair geyser
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we can only make it 2, if it's 1152

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because we can't use the digit 2 again

hoary spoke
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But also, we can't use 1 twice

fair geyser
#

oh

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we can't

hoary spoke
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Ya

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No repetitions allowed

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It is written in the question

fair geyser
#

you're right

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83
74
65 can't
56 can't
47
38

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so those 4 should work

hoary spoke
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Okay.....

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I think I can solve it now

fair geyser
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if it ends in 56, the other two digit must add up to 7 or 16

hoary spoke
#

Yeah....

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So they can be.....

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16

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34

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61

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97

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43

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79

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So I have to just check one by one?

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If they satisfy the question's condition or not?

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Thank you very much

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You are my messiah

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Bot, i am done

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,calc 99/9

wraith daggerBOT
#

Result:

11
hoary spoke
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. close

fair geyser
#

you don;t have to check they all should work

hoary spoke
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Oh

fair geyser
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just not the 61 or 16

hoary spoke
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6

hoary spoke
fair geyser
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why not

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they are divisible by 36

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that was the condition

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they are because they are divisible by 4 and 9, which is equivalent

hoary spoke
#

Wait wait I think i got it

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hm...

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Thanks

#

.close

cedar kilnBOT
#
Channel closed

Closed by @hoary spoke

Use .reopen if this was a mistake.

#
Available help channel!

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Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
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• Be polite and have a nice day!

Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.