#help-13

428200 messages · Page 468 of 429

noble igloo
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(then multiply by this - but thats trivial since this is well just a constant)

noble igloo
#

<@&286206848099549185>

cedar kilnBOT
#

@noble igloo Has your question been resolved?

steel karma
#

top answer does it by integrating just like ur trying to do

cedar kilnBOT
#

@noble igloo Has your question been resolved?

noble igloo
#

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#
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crimson sedge
#

is $\frac{2\cos x-1}{\sqrt{1-\cos^2 x}}=\tan(x/2)$

wraith daggerBOT
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XxmastersmithxX

south tundra
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No

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You could check that in desmos btw

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Or any other graphing calculator

deft forum
#

No

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$\frac{1- \cos x}{\sqrt{1-\cos^2 x}}=\tan(x/2)$

wraith daggerBOT
south tundra
#

Absolute value tho

deft forum
#

Yup

crimson sedge
south tundra
cedar kilnBOT
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bitter salmon
cedar kilnBOT
bitter salmon
#

Can someone help me
I do not know how to solve number 3 and 4

tropic oxide
#

how familiar are you with basic trigonometry?

south tundra
#

Use definition of tan in a right triangle in order to get expressions for tan(25) and tan(a) in 3

tropic oxide
#

like, SOHCAHTOA

bitter salmon
#

yeah i know a bit
sin = opposite/ hypotenos
cos = adjacent / hypotenos
tan = opposite/ adjacent

south tundra
#

Okay, what would tan(25) be by looking at the triangle on the right?

bitter salmon
#

Ohhhh waiit wait so
tan (25) = h /12??

south tundra
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Yes, can you solve for h from here?

bitter salmon
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yep thanks

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i got 5.6

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Im solving the other triangle now

cedar kilnBOT
#

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bitter salmon
cedar kilnBOT
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karmic terrace
#

I need help with number 3

cedar kilnBOT
karmic terrace
#

I keep getting a surd number but when i look at the answers its just a fraction

dull anchor
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what have you tried?

karmic terrace
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Sorry if its a bit messy

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I got (-79 ± √ 6241 - 540)/-2

knotty moat
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we have two equations l + b = 7.9 and lb = 13.5

violet rapids
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Equations are set up

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Correctly

dull anchor
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you got -x^2+7.9x-13.5 = 0

karmic terrace
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Oh ok

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I try

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I got it

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Thanks big

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.close

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dull anchor
#

no problem😁

cedar kilnBOT
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wanton glacier
#

$r^5+r^6=r^{11}?$

cedar kilnBOT
wraith daggerBOT
#

hyperlix26

violet rapids
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Careful

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Does this look like a law of indices?

wanton glacier
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no

bright surge
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what's your question?

violet rapids
bright surge
#

maybe find values of r?

wanton glacier
violet rapids
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Yel

dull anchor
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bruh

violet rapids
#

Yep

wanton glacier
violet rapids
#

Know the exponent rules!!!

wanton glacier
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alright

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thanks

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.close

cedar kilnBOT
#
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wanton glacier
#

.reopen

cedar kilnBOT
#

wanton glacier
wraith daggerBOT
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hyperlix26

wanton glacier
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$3ar+r^2?$

wraith daggerBOT
#

hyperlix26

tropic oxide
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no

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$a + ar + ar^2$ is not equal to $3ar + r^2$

wraith daggerBOT
wanton glacier
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but it's 3a

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$3a+r+r^2$

wraith daggerBOT
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hyperlix26

wanton glacier
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is that it

violet rapids
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No

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@wanton glacier none of these are like terms!

jaunty mural
#

$$5\times2+5\times2^2+5\times2^3$$
$$= 5\times2+5\times4+5\times8$$
$$= 3\times5\times2+4$$

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Is what you're trying to do?

wraith daggerBOT
#

Shuri2060

jaunty mural
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You seem to have to wrong idea about how to factorise

cedar kilnBOT
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@wanton glacier Has your question been resolved?

wanton glacier
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oh wait that's it

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you can't separate r and a

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so it stays like that

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all of the terms have a

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so you can factor that out

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$a(r^2+r+1)$

wraith daggerBOT
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hyperlix26

jaunty mural
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Yes. Better.

wanton glacier
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$ar^5(r^2+r+1) \implies ar^7+ar^6+ar^5$ right

wraith daggerBOT
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hyperlix26

wanton glacier
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<@&286206848099549185>

jaunty mural
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not implies.

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equals.

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And you can check equality of algebraic expressions in wolfram.

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,w simplify [a r^5(r^2+r+1) - (a r^7+a r^6+a r^5)]

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the heck?

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when its not being dumb that is

wraith daggerBOT
jaunty mural
wanton glacier
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hmm

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wait

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since I have this $ar^7+ar^6+ar^5$

wraith daggerBOT
#

hyperlix26

wanton glacier
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I can do this right? $r^5(a+ar+ar^2)$

jaunty mural
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Yes, you can check in wolfram (with spaces or on the actual website)

wraith daggerBOT
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hyperlix26

jaunty mural
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if your manipulations are correct or not

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see above

wanton glacier
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,w simplify r^5(a+ar+ar^2)

wraith daggerBOT
wanton glacier
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alright

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thanks

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.close

cedar kilnBOT
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crimson sedge
#

Hello

cedar kilnBOT
crimson sedge
#

For the derivative of e and log, if we apply the chain rule then why do we need ln e or ln a?

lone rivet
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what do u mean

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could u rephrase that

dense wing
crimson sedge
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If we have function x^2 and we take the derivative

lone rivet
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its 2x

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d/dx

crimson sedge
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2(x) (1)
dense wing
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$\dv{x}a^{u(x)}=a^uu'(x)\ln(a)$

wraith daggerBOT
crimson sedge
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Yes, why ln(a) is there?

dense wing
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$\dv{x}a^x=a^x\ln(a)$

wraith daggerBOT
lone rivet
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i've never seen this before

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actually stumped

dense wing
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$\dv{x}a^x=\dv{x}e^{\ln(a)x}=\ln(a)e^{\ln(a)x}=\ln(a)a^x$

wraith daggerBOT
lone rivet
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the derivative of a^x is xa^(x-1)

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oh

dense wing
crimson sedge
dense wing
#

It isn't.

dense wing
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once

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a^x is a function

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u(x) is a function

lone rivet
dense wing
#

you have a single layer of composition

lone rivet
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THIS IS A TO THE POWER OF X

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ok i understand

dense wing
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the derivation of the a^x rule requires chain rule on e^u(x)

crimson sedge
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Got it.

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Thank you very much @dense wing 😊

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cedar kilnBOT
#
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coarse cloud
#

If I were to calculate the log of a scientifically notated number ig 5*10^5 could I simply remove the *10^5, calculate the log of 5 and then add it back in after?

graceful karma
#

$\log(a \cdot b) = \log(a)+\log(b)$

wraith daggerBOT
#

PapaBread

toxic owl
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beat me to it haha

graceful karma
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Indeed

coarse cloud
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Thank you sm

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both!

graceful karma
#

Np

coarse cloud
#

Okay just you

#

.close

cedar kilnBOT
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glacial solstice
cedar kilnBOT
glacial solstice
#

I need help with vectors, the question just confuses me

jaunty mural
#

If you draw a diagram...

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it wouldn't be as confusing, I hope

glacial solstice
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Alright lemme try

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oh yeah i did it

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For AB i got b

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let me try CD

jaunty mural
#

idk how you think you were going to do a vectors question with no diagram

cedar kilnBOT
#

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mighty quarry
cedar kilnBOT
mighty quarry
#

im lost

violet rapids
#

is this a quiz

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or a test

mighty quarry
#

sat prep

cedar kilnBOT
#

@mighty quarry Has your question been resolved?

mighty quarry
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summer arch
cedar kilnBOT
summer arch
#

shouldn't it be g o 1A

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and not 1A o g

cedar kilnBOT
#

@summer arch Has your question been resolved?

spring bolt
#

Can we get any context at all?

summer arch
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sure

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sorry about that

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It's the proof that functions can have only one inversive function

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We assumed that f^-1 and g are the inversive functions of function f

spring bolt
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what are A and B?

summer arch
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1A: A -> A

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1B: B -> B

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f: A -> B

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f^-1: B -> A

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g: B -> A

spring bolt
#

if you want to flip them, it would need to be $g \circ 1_B$, then

wraith daggerBOT
spring bolt
#

It should work either way. Why don't you try both?

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...but the original is correct. g maps B to A, $1_A$ maps A to A, so $1_A \circ g$ maps B to A to A

wraith daggerBOT
cedar kilnBOT
#

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cedar kilnBOT
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cedar kilnBOT
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hardy umbra
#

I am having trouble finding the second derivative here. Its a summation of two product rules correct?

gaunt hamlet
#

Yea

hardy umbra
#

I think I figured out my mistake as soon as I posted it. Just messy handwriting...

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thanks for confirming though

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hollow sapphire
#

.reopen

gaunt hamlet
#

You can't reopen another person's channel

cedar kilnBOT
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wet gorge
cedar kilnBOT
#

@wet gorge Has your question been resolved?

wet gorge
#

<@&286206848099549185>

dire geode
#

This doesn't really look like math

cedar kilnBOT
#

@wet gorge Has your question been resolved?

wet gorge
#

it's in my computer science program as a math class

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it seems very similar to set theory to me but idk

dire geode
#

Regular expression is definitely not a math thing

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You're more likely to get help in a CS server

toxic owl
#

The notation might be math related but the theory and specifically what property it is relates more to CS

cedar kilnBOT
#

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wet gorge
#

i cant find any CS servers

cedar kilnBOT
wet gorge
#

if someone would like to help with my original question i would appreciate it

obsidian coral
radiant topaz
#

.

cedar kilnBOT
#

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mental torrent
#

help?

cedar kilnBOT
mental torrent
tropic oxide
#

,rccw

wraith daggerBOT
tropic oxide
#

what is giving you trouble here?

mental torrent
#

how do i start?

tropic oxide
#

have you worked with piecewise functions before?

mental torrent
#

nope

tropic oxide
#

so this is your first time seeing a definition like this?

mental torrent
#

yes

tropic oxide
#

okay

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are you familiar with programming to any extent

mental torrent
#

a little

tropic oxide
#

ok great

def f(x):
    if x <= -2:
        return -4
    else if -2 < x < 1:
        return x
    else if x >= 1:
        return x^2 - 1
#

this is that function definition translated into python (with some small syntax non-conformities)

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does this help you understand the definition better

mental torrent
#

yup ok

tropic oxide
#

are you able to continue from here

mental torrent
#

do i substitute in -1?

tropic oxide
#

i mean...

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yes, if you so insist,

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but you have to identify where to substitute it into

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based on those case conditions in the function defn

mental torrent
#

oh

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i’m kinda slow haha i don’t get it

tropic oxide
#

okay, so: which of the following three inequalities is satisfied by x = -1?

x <= -2
-2 < x < 1
x >= 1

mental torrent
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the second

tropic oxide
#

okay, and what's the formula next to it in the definition?

mental torrent
#

x

tropic oxide
#

so what's f(-1)?

mental torrent
#

-1?

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yeah all cool me too

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i think they are separate equations

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i just checked my answer sheet and it says -4 lol what

tropic oxide
tropic oxide
mental torrent
#

oh then the answers are probably wrong right?

tropic oxide
#

are you sure you're looking in the right place for the answer key

mental torrent
#

yeah idk it says -4

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i’m pretty sure it’s -1 tho

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thanks for helping me out!

#

.close

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wide furnace
cedar kilnBOT
wide furnace
#

The supposed answer to this question is 0.65

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But to my understanding it should be 0.8

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Can anyone explain why?

tropic oxide
#

you're confusing 'independent' with 'mutually exclusive'

wide furnace
#

So how do you work it out?

faint viper
#

P(A)+P(B)-P(A and B)

tropic oxide
#

recall what the term 'independent events' actually means

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and do that ^

wide furnace
#

Oh my

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A mental atrophy on my part then

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Thanks

#

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fluid swift
#

Show that angles MNR and RAN are equal.

cedar kilnBOT
#

@fluid swift Has your question been resolved?

crimson sedge
fluid swift
crimson sedge
#

Is RA a bisector?

fluid swift
crimson sedge
#

DR too?

fluid swift
#

yes

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fluid swift
#

.reopen

cedar kilnBOT
#

cedar kilnBOT
#

@fluid swift Has your question been resolved?

fallen heath
fluid swift
bright surge
#

<@&286206848099549185>

cedar kilnBOT
#

@fluid swift Has your question been resolved?

solid quarry
#

@fluid swift show that points M A R N lie on a circle

steel karma
#

im curious

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i dont think they are necessarily cyclic

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ping me if u have proof

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or at least not enough info from the question to show they are cyclic

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@fluid swift post the full info of the question if u have it

fallen heath
crimson sedge
#

I am clueless.
I still can't prove it

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I am bad at geometry :(

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Is this an Olympiad question?

fallen heath
#

if I'm not wrong about this, it's probably an entrance level oly question (@_@;)

fluid swift
solid quarry
#

i know srry

fallen heath
#

Eden anything you tried?

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For all I know, I can see anti-parallel lines and recall my oly. camp which I flawlessly bunked [and now rethink my life choices]

fluid swift
#

I messed around with the circle D for a bit. Found nothing.

crimson sedge
fluid swift
#

IMO 2004 p1 - Maybe this is an xyproblem moment :\

fallen heath
#

hence proved lmao

fallen heath
crimson sedge
#

I need to start studying geometry from basic again

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Ping me if u get sol

steel karma
#

im imagining ok suppose it is cyclic, then what if I take the centre of the circle to be A'

#

A' is an angle bisector too, just like A

#

What's the difference between A and A' then in the construction?

fallen heath
#

Apart from it being an IMO problem and the GeoGebra calculator confirming the facts, I'd need some more time if you want more proof lol

steel karma
#

hold on

#

i see now

#

A'RD is collinear

#

while ARD is not in the diagram

fallen heath
fallen heath
#

@fluid swift If you're not exclusively looking for a geometric proof, maybe this could satisfy you atm:

fallen heath
#

Do you know sine law?

fluid swift
#

so

#

well

fallen heath
#

Ah'

fluid swift
#

yes i can prove using sine law

fallen heath
#

smh, so bad :c I figured the trig solution

fluid swift
#

but i dont ws=ant to do that

fallen heath
#

but just can't find a geometric one

#

however there being a trig solution implies similarity is due

crimson sedge
#

Uh I mean don't use sine cos
But instead use ratio side

#

Lik sin =ab/BC like that

fallen heath
#

there you go.. just focus on proving this is cyclic lol

fluid swift
crimson sedge
#

Nvm

steel karma
#

did you just go straight to international math olympiad and dunk it in help

fluid swift
#

no

steel karma
#

lol

fluid swift
#

this is practice

steel karma
#

without ever doing IMO

fallen heath
#

it's not that tough bm, you could do it with trig easy, but uhh

#

mate's looking for a geometry soln.

fluid swift
#

nvm i guess i can stick with trig.

#

.close

cedar kilnBOT
#
Channel closed

Closed by @fluid swift

Use .reopen if this was a mistake.

fallen heath
#

wait Eden lol

steel karma
#

what next

crimson sedge
#

Oh

fallen heath
#

wow (@_@;)

steel karma
#

i claim this

crimson sedge
#

Wait how do I solve it help

steel karma
#

.open

fallen heath
#

no clue what you did >_<

#

.claim

#

I claim thee

crimson sedge
#

.claim 😎

fallen heath
#

*this

crimson sedge
#

Wut

#

Shit

cedar kilnBOT
#
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Show your work, and if possible, explain where you are stuck.
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fallen heath
#

claim

cedar kilnBOT
fallen heath
#

UwU

knotty moat
#

lol

steel karma
#

i just put the circumcentre of the MRN on the diagram

#

that's all i labelled

crimson sedge
fallen heath
#

to prove ANRM is cyclic

crimson sedge
#

Here

steel karma
#

pls

#

my diagram

fallen heath
#

no mine wth,, my channell

knotty moat
#

..

steel karma
#

yours is ambiguous

#

if MRA = ARN then they dont need to be concyclic

knotty moat
#

its looks cyclic already so it is cyclic

fallen heath
#

except given MRA not ARN UwU

steel karma
#

that was what tripped me up earlier

#

i did exactly what u did

#

i reduced it to ur diagram

#

and then was like hey taht doesnt need to be concylic

#

lol

fallen heath
#

with trig it's easy to see: sin(AMR) = AR (sin(MAR) / MR) = AR(sin(NAR) / NR) = sin(ANR)

steel karma
#

what is S

knotty moat
#

nvm I step out of trigo

gentle lintel
fallen heath
#

👀

crimson sedge
#

Yes

fallen heath
#

wha-

crimson sedge
#

See

fallen heath
#

why-

steel karma
crimson sedge
fluid swift
fallen heath
#

implication: AMR + ANR = 180 or AMR = ANR ; but AMR = ANR is ruled out atq

steel karma
#

i see

fallen heath
#

so we done UwU

#

but

#

the thing is

steel karma
#

nice>

fallen heath
#

how to do geometrically T_T

gentle lintel
#

(ansh come help me later ;-;)

steel karma
#

prove the sine rule geometrically

#

and then just use it

#

or cosine rule

#

cosine rule works the same here

crimson sedge
#

Oh wut this was so easy there was just a trick to it

fallen heath
steel karma
crimson sedge
fallen heath
#

How tf is AMR = ANR = 90°?

knotty moat
#

I was trying to prove it congruent lol

crimson sedge
#

This

steel karma
#

of unnecessary information

#

in the original pic

fallen heath
#

Yeah lmao

crimson sedge
fallen heath
#

reducing it is the best lol

knotty moat
#

nothing else is given in question?

#

except the diagram

fallen heath
#

bruh ... you've taken too much wine

knotty moat
#

ok

crimson sedge
#

Yeah

#

Uh NVM I wil go sleep

steel karma
#

tbh i think its fine

#

u use sin rule to prove it

#

since sin rule is proved geometrically also sotrue

fallen heath
#

Ikr

#

but then one must be able to see it without trig as well

steel karma
#

its an olympiad problem

#

whatever it takes lol

knotty moat
#

we can join points M and N?

#

lol

#

and

#

it is a isosceles triangle

#

angle NMR = angle RNM

#

what is its use lol

#

nvm

fluid swift
#

nvm i'll just use trig

steel karma
#

i like combinatorics olympiad the most

#

those are the most fun to me

#

even tho i suck at those

fallen heath
#

a question for you as well then

steel karma
#

no like geometry

fallen heath
#

Help me out with this one:

steel karma
#

post

knotty moat
#

I will just store questions to solve later lol

fallen heath
#

Number of n lettered words made out of n A's and n B's such that the number of A's from the left is at all times not less than the number of B's from the left.

steel karma
steel karma
#

yes

#

this question that was posted

knotty moat
#

cool

#

lol

steel karma
#

if you make it out of n As and nBs isnt it a 2n lettered word

#

"A's from the left is at all times greater than the number of B's from the left."

#

what does this mean?

knotty moat
#

AAABB

steel karma
#

A's from the left?

knotty moat
#

type series

steel karma
#

B's from the left?

knotty moat
#

ig

#

oh nvm

fallen heath
#

Like.. AABABAA is valid

#

because 2A before first B and 3 A before 2nd B

#

but AABBB isn't valid

steel karma
#

ok so n lettered words

fallen heath
#

because there's 2 A before 3 Bs

steel karma
#

it's a n lettered word

#

made up of As and Bs

fallen heath
#

yeah

steel karma
#

not n As and n Bs

#

or is it a 2n lettered word

#

with equally many As and Bs

fallen heath
#

n lettered word

#

(@_@;)

steel karma
#

ok

knotty moat
#

no value of n?

#

just a variable?

fallen heath
#

nu 0_0

knotty moat
#

lol

steel karma
#

my first instinct is to write a recursion

steel karma
#

so we split it into the difference of total As and Bs

gentle lintel
#

the first letter must be A

steel karma
#

or for some string that is valid let f(string) by the difference in the number of As and Bs

gentle lintel
#

big hmm

steel karma
#

and we can sum across all strings of length n

#

i should write it down

knotty moat
#

I got nothing but I will watch

gentle lintel
#

so suppose we have n A’s and n B’s in two bags

#

how many ways can we form a sequence

#

such that there are always less A’s than B’s?

knotty moat
#

@fallen heath you have algebra question? I want to see if I can solve lol

#

or maybe later

crimson sedge
#

Is the solution algebraic or numeric?

gentle lintel
#

we’ve got two counters that can count from 0 to n, how can we always have the left counter displaying a bigger/equal number

#

maybe this is easier

steel karma
#

this is idea

knotty moat
#

lol

crimson sedge
#

So if there are p A's ther can only be p-1 B's or less than that such that it starts with 2 A's

fallen heath
#

Wait lemme figure one.

knotty moat
#

ok

steel karma
#

cause if you have a valid string

#

you can either append an A or B to the end of it

#

to get a string of length n+1

#

if the string ends with the same number of As and Bs you cant append a B

crimson sedge
steel karma
#

that's where this chart be comes from

steel karma
#

you can append an A or B at the end

#

to get a string of length n+1

#

and if the string ends with the same numbers of As and Bs you cant append a B

fallen heath
# knotty moat ok

there you go (@_@;) but I already know the ans. so it's just for gift sake-

knotty moat
#

lol

#

..

#

let me try lol

steel karma
#

that's a recursive way to find the number of ways

#

quickly

#

but idk how it relates to a simple formula

fallen heath
#

(@_@;) if it's a recursion.. maybe I can follow from there

#

Do you know one that helps here?

steel karma
#

nope

#

im looking at the first row

#

1 / 0 / 1 / 0 / 2 / 0 /5 / 0 / 14 / 0 / 42

#

what are these numbers

#

it's like a pascals triangle

#

but cut

fallen heath
#

welp, think about it and lemme knowww (ヘ・_・)ヘ┳━┳
I think I need to revise how sine law was derived in the first place smh

gentle lintel
#

i arrived at y² - 22y - 3 = 8√y

fallen heath
#

XD question's free for anyone..

gentle lintel
#

is there an elegant way to solve this

steel karma
#

These are catalan numbers

#

1,1,2,5,14,42

fallen heath
#

wha-

#

howw

steel karma
#

🤷‍♂️

fallen heath
#

n = 3 is already out of your sequence lol

gentle lintel
#

me dumb

fallen heath
#

n =3 has AAA, AAB, ABA

fallen heath
fallen heath
steel karma
#

i was looking at the top column

fallen heath
#

it has a very exact solution that gives a very exact answer

#

an irrational root

gentle lintel
steel karma
#

the recursive formula is:

For n odd:
f(n+1) = 2f(n)

For n even
f(n+1) = 2f(n) - C(n/2) where C(x) is the xth catalan number

gentle lintel
#

so by common sense i do (x² + ax + b) (x² + px + q) expansion

steel karma
#

i was looking at what we are subtracting

gentle lintel
#

then do annoying as fuck system

steel karma
#

and noticed it is the catalan numbers

gentle lintel
#

👏

#

there should be elegancy somewhere

fallen heath
steel karma
#

i found the name of ur problem

#

"dyck words"

fallen heath
#

there is, but you'll blow your brains when you realise it

#

shut up bm lmfao

gentle lintel
#

sure

#

sad jj

fallen heath
#

*when you realize the solution yourself (@_@;)

gentle lintel
#

i dont care tell me :((

fallen heath
#

I read on dyck words too.. not the same thing tho

#

one hint and it'd be out there in the open smh

#

(the solution)

gentle lintel
steel karma
#

im just reading on catalan numbers

#

wow this is a rly big field of maths i had no clue about ;')

#

or idk how big it is

#

but a lot of interesting things to learn it seems

fallen heath
#

maybe tmrw :p

#

.close

cedar kilnBOT
#
Channel closed

Closed by @fallen heath

Use .reopen if this was a mistake.

fallen heath
#

I did something similar previously in hs but uh (ヘ・_・)ヘ┳━┳ I forgot how

cedar kilnBOT
#
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After 15 minutes, feel free to ping <@&286206848099549185>.
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scenic cargo
#

What does the number outside of a square root mean? Example:

scenic cargo
#

Does it mean 2 times the square root?

stable solstice
#

yea

scenic cargo
#

Ahh, i see, thanks man

#

.close

cedar kilnBOT
#
Channel closed

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cedar kilnBOT
#
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.

azure canyon
cedar kilnBOT
azure canyon
#

can someone help me find a

#

y = a(x - h)^2 + k

#

yea so i got everything but a, i tried puting in the given point but got it wrong

#

yes

#

ohhh

#

i got it now! thanks!!!!!

#

-1/9

#

no

#

tf

#

why you need a girl?

#

i see you i see you bro

#

LMAO

#

we all need some, we kinda down bad huh

#

send me the problem bro

#

im two time back to back gold champ

obsidian coral
#

But why? That's weird

dire geode
#

@brisk forge stop being weird

azure canyon
#

LMAO

#

MANS DOWN BAD

cedar kilnBOT
#

@azure canyon Has your question been resolved?

cedar kilnBOT
#
Channel closed

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#
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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!

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cedar kilnBOT
stark creek
#

yo anyone know y we do L = 50 - W?

obsidian coral
#

,rotate

wraith daggerBOT
stark creek
#

y not W = 50 - L

obsidian coral
#

You can, if you want

stark creek
obsidian coral
#

It should

stark creek
obsidian coral
#

Yes

stark creek
#

oh wait let me ask another anser

#

*answer

cedar kilnBOT
#

@stark creek Has your question been resolved?

cedar kilnBOT
#
Channel closed

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cedar kilnBOT
#
Available help channel!

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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!

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copper peak
#

does anyone know how to enter a matrix in mymathlab by code, instead of manually selecting from the menu

copper peak
#

when i paste this @MATX{{-3};{1};{1}}, it works perfectly

#

when i type it out it doesnt work

cedar kilnBOT
#

@copper peak Has your question been resolved?

exotic elk
#

u can do it in wolfram alpha like {{1, 2, 3}, {3, 2, 1}, {1, 2, 3}} + {{4, 5, 6}, {6, 5, 4}, {4, 6, 5}} for example

#

or symbolab with

\begin{pmatrix}2&3&4&5\\ 6&7&8&9\end{pmatrix}```
wraith daggerBOT
#

MattDog_222
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

#

BritS

$\begin{pmatrix}6&9&6&9\\ 6&9&6&9\end{pmatrix}$
crimson sedge
#

There you go

copper peak
#

yeah but these dont work in mymathlab which is my homework website

#

and entering it manually from the menu is very tedious

crimson sedge
#

Excuse me did you say mymathlab?

#

Nvm

copper peak
#

mylab math

exotic elk
#

that doesn't show the code

copper peak
#

yeah it doesn't

exotic elk
#

try

\begin{bmatrix}3&3\\ 23&46\end{bmatrix}```
#

bmatrix might work

crimson sedge
#

||Why did I see these numbers?|| <-- ignore this

copper peak
wraith daggerBOT
#

MattDog_222
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

exotic elk
copper peak
#

so maybe i have to add something before it?

exotic elk
#

could try \[\begin{bmatrix}3&3\\ 23&46\end{bmatrix}\]

wraith daggerBOT
#

MattDog_222

exotic elk
#

or dollar signs $\begin{bmatrix}3&3\\ 23&46\end{bmatrix}$

wraith daggerBOT
#

MattDog_222

crimson sedge
#

Try writing [[6 9][6 9]]

copper peak
#

i tried it

#

there must be a way

exotic elk
#

idk im just fishin, [1,2;3,4]

copper peak
#

okay i give up

#

thanks for helping tho lol :)

#

.close

cedar kilnBOT
#
Channel closed

Closed by @copper peak

Use .reopen if this was a mistake.

cedar kilnBOT
#
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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!

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sterile maple
#

Hi,
I have no idea how to solve this sum. I tried making a triangle with an angle 30 at the corner but it hasn't worked. Could someone please help? Thank you

dusty hazel
#

Right, so um the triangle ABC is equilateral correct?

sterile maple
#

yes

dusty hazel
#

What does that tell you?

#

About the angles of the triangle.

sterile maple
#

all are 60

dusty hazel
#

Correct.

#

Since the triangle def is formed by lines parallel to the original triangle, they both should be similar
True?

sterile maple
#

ya

dusty hazel
#

So each angle of def is?

sterile maple
#

all are 60 even the inner ones

dusty hazel
#

Correct.

#

So the inner triangle is equilateral.

sterile maple
#

yes.

dusty hazel
#

Since the original triangle had sides equal to 10cm, and new one has 1cm less in all directions.
Shouldn't each side be 2cm less than 10?
It's not I think, still.

sterile maple
#

it's not that simple unfortunately

dusty hazel
#

I thought that was the case this time.

#

Haha, my bad.

#

I'll calculate

sterile maple
#

So I thought of making a smaller triangle

#

like this

dusty hazel
#

Where the perpendicular is 1cm.

#

Label the points it'd be easier.

#

So we get the base √3 in this smaller triangle, no?

#

Same for all other sides?

sterile maple
#

Yes

dusty hazel
#

Since equilateral triangle is a regular figure.

#

So yeah new sides of this triangle,
Shouldn't they be like 10-(2√3)

#

In cm.

sterile maple
#

Oh so

dusty hazel
#

so perimeter would be three times this.

#

Unless we did something wrong.

sterile maple
#

30 - 6root3 then?

dusty hazel
#

I believe.

sterile maple
#

Perfect This is the answer in my tb

#

Thanks man!

dusty hazel
#

You're welcome!

sterile maple
#

.close

cedar kilnBOT
#
Channel closed

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#
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cedar kilnBOT
dusty hazel
#

I figured some stuff on my own too.

#

First of all we have the general form
ax²+bx+c=0
Where a,b,c are odd and integers.

#

a≠0

#

Also if the equation has unreal roots that proves the thing easily, so we will talk about real roots only.

#

So ∆≥0

#

Also, for rational roots, ∆ must be a perfect square of a rational number.

#

So we have to contradict this.

#

also ∆=b²-4ac
b² is odd, 4ac is even, ∆ is definitely odd.

#

Also, b a and c are integers, therefore ∆ is an integer.

#

Let ∆ be square of some integer $\sigma$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

Sigma is odd as ∆ is odd.

#

therefore ∆=b²-4ac
And $∆ =\sigma^2$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

$\sigma^2=b²-4ac$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

$4ac= b² - \sigma^2$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

b and sigma both are odd therefore their difference is even. This is what bugs Me, we had to contradict this from happening.

cedar kilnBOT
#

@dusty hazel Has your question been resolved?

dusty hazel
#

<@&286206848099549185>

cedar kilnBOT
#

@dusty hazel Has your question been resolved?

jaunty mural
#

I suspect if you take this mod 4, the result might come out

dusty hazel
#

Oh thanks, finally someone saw my question.

jaunty mural
#

or some other mod if not thay

dusty hazel
jaunty mural
#

what?

dusty hazel
#

Elaborate what you meant please, I didn't follow.

jaunty mural
#

consider cases in modular arithmetic

#

It doesnt work for now, actually.

#

But thats the first thing that came to mind

#

Ah ok, I can see a factorisation

dusty hazel
#

Right.

jaunty mural
dusty hazel
#

Am I not?

#

I can factorise that surely.

#

Also b and $\sigma$ are odd.

#

let $b =2k+1 and \sigma =2h+1$

wraith daggerBOT
#

Sakata Yaksha

#

Sakata Yaksha

jaunty mural
#

what?

dusty hazel
#

I mean

dusty hazel
jaunty mural
#

You literally wrote it in this form

#

There is an obvious factorisation to do here, surely.

dusty hazel
#

Ik

#

I'm doing that obviously.

#

$(b+\sigma)(b-\sigma)$

wraith daggerBOT
#

Sakata Yaksha

jaunty mural
#

right.

dusty hazel
#

I also concluded

jaunty mural
#

Then there should be cases to consider in modular arithmetic or similar

dusty hazel
#

b and $\sigma$ are both odd.

wraith daggerBOT
#

Sakata Yaksha

limpid plume
#

Both b - sigma and b + sigma should be even

dusty hazel
dusty hazel
# limpid plume Both b - sigma and b + sigma should be even

Correct, we are contradicting though. Please read all my previous messages if you can, I'd appreciate it. I concluded lots of stuff, and it'd make us all understand what I am approaching and what I should have done if that's now what I should have done.

limpid plume
#

So, the statement you have started with - does that have any counter examples?

If you're arriving at a contradiction then the statement might jot actually be true

dusty hazel
#

I mean I have to prove it does not have rational roots, so I assumed it has rational roots. Now we're contradicting this.

limpid plume
#

Let me try something and then come back if I find something

dusty hazel
#

Sure, thanks!

limpid plume
jaunty mural
#

do we not get a contradiction mod 8?

dusty hazel
#

What's that?

jaunty mural
#

have you seen modular arithmetic?

dusty hazel
#

Like I told, that's not what I can use in this question.

jaunty mural
dusty hazel
#

Also, I have not.

jaunty mural
#

are you sure you can't use it?

dusty hazel
#

I can obviously.

#

I'm not allowed to.

#

That's what I meant.

jaunty mural
#

why

dusty hazel
#

My bad.

jaunty mural
#

modular arithmetic is no different from essentially considering remainders

#

you can literally do this with just the numbers and it makes no difference in logic

dusty hazel
#

Oh the name seemed fancy lmao.

#

So, can you give an example real quick?

jaunty mural
#

you should lookit up

#

modular arithmetic

#

quicker

#

than me saying

#

Look on brilliant or similar

#

Numbers mod 4 are 0, 1, 2 or 3 for example...

dusty hazel
#

mod 4
I thought that was |4|

#

Absolute value function.

#

I'll google it real quick then.

limpid plume
#

@dusty hazel Can we prove the discriminant of the new equation with k as variable is less than zero?

#

And even if it is not less than zero, it is not a perfect square?

limpid plume
dusty hazel
#

Yes, I got it.

#

We use mod only and only for modulus generally.

#

So I didn't know earlier.

dusty hazel
#

But if it is a perfect square, the roots are automatically rational.

limpid plume
#

If it's less than zero we have a very solid proof

dusty hazel
#

Yes indeed.

limpid plume
#

And I meant the discriminant of the newer equation

dusty hazel
#

Which one, can you mark that ?

#

Or reply to it or something.

limpid plume
dusty hazel
#

I'm extremely sorry, I did not see this at all. I'll check.

limpid plume
#

Oooooooh wait wait

#

My god it should be positive instead of negative, my baf

dusty hazel
limpid plume
#

Let me do it from scratch

dusty hazel
#

Hey

limpid plume
#

The first one was correct

dusty hazel
#

k²+k+4ac...

limpid plume
#

I'm sorry for confusing you

limpid plume
dusty hazel
#

Yeah lol, also this is exactly what my proof looks like.

dusty hazel
#

Just we use 2k+1 and stuff for odd integers now.

limpid plume
#

Yes, I just assumed your a as 2a + 1 so I can make it necessarily odd from the start 👍

jaunty mural
#

I'm not saying modular arithmetic necessarily helps btw. But it is something worth trying

dusty hazel
#

You told to use mod 8 though, correct?

jaunty mural
#

squares cannot be 3 mod 4 for example

#

didnt work though

#

yes mod 8

#

To make some parity argument

dusty hazel
#

Ah, alright I will keep that 8 in mind.

#

So

#

$4ac= b² - \sigma^2$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

$4ac=(b+\sigma)(b-\sigma)$

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

Ohh lol I figured it out maybe.

#

If only this is correct, I'll be done for the day and sleep nicely.

#

Yes, I'm very positive I did it.

#

!!!!!!

#

@jaunty mural thanks, 8 really is a good number.

#

@limpid plume thanks, for your help.

#

So we prove this like this

#

The difference of squares of two odd integers is a multiple of 8!

#

While on LHS we have 4ac, where a and c are odd.

#

Which contradicts.

dusty hazel
limpid plume
#

Also

#

Alternative proof I justade

#

Made*

dusty hazel
#

Yes, sure I'd like to have a look.

#

$4ac= 8n$ as $b²-\sigma^2$ is always a multiple of 8.

wraith daggerBOT
#

Sakata Yaksha

dusty hazel
#

We get, $ac=2n$ which is never possible as a and c are odd.

wraith daggerBOT
#

Sakata Yaksha

jaunty mural
#

👌

limpid plume
#

I apologise for bad handwriting

dusty hazel
#

Thanks, I'll also look everything about modular arithmetic today.

dusty hazel
limpid plume
#

Competitive exams have done so much harm to me it's not even funny anymore

#

Not only it gave me depression at one point, it also made my handwriting bad an my ability to write subjective answers bad

#

MCQs are just not the way to live 😭

dusty hazel
#

Hmmmm, you're Indian I assume? (A very random guess, no offense)

limpid plume
#

Yes

#

And none taken

dusty hazel
#

I see, I'm checking your proof, we'll have our talk then.

#

Yes, your proof was all worth it.

#

Thanks mate.

#

Now, let's take this to dms and close the channel as we're done here.

limpid plume
#

I wrote some letters wrong in the last I think, but you got the idea right?

dusty hazel
#

.close

cedar kilnBOT
#
Channel closed

Closed by @dusty hazel

Use .reopen if this was a mistake.

#
Available help channel!

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Remember:
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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gray vine
#

I did something wrong here, but I don't know what:
sin(2x) = 4sin(x)
sin(2x) - 4sin(x) = 0
sin(2x) = sinxcosx + cosxsinx = 2sinxcosx
2sinxcosx - 4sinx = 0
sinxcosx - 2sinx = 0
cosx - 2 = 0

dense wing
#

You divided by sin(x)

gray vine
#

Is that not permissible?

dense wing
#

it is not

#

cause it clearly loses solutions

trail jackal
#

you only can divide by something nonzero. So if you divide by sinx, you also need to deal with the case that sinx=0

gray vine
#

you also need to deal with the case that sinx=0
Why's that?

dense wing
#

cause sin(x) is a factor of the LHS...

#

apply zero product property.

#

ab=0 iff a=0 or b=0

trail jackal
#

you get sinx(cosx-2)=0 so either sinx=0 or cosx-2=0

gray vine
#

ah that's true

#

well cosx-2 = 0 can't be correct because cosine can't be greater than 1

dense wing
#

yep.

gray vine
#

so we're left with sin(x) = 0, which equals πn/2 + 2πn

#

oops

#

i mean π + πn

dense wing
#

Yes, sin(x)=0 when x=pi*n, n in Z

gray vine
#

alright thanks 🙂

#

.close

cedar kilnBOT
#
Channel closed

Closed by @gray vine

Use .reopen if this was a mistake.

cedar kilnBOT
#
Available help channel!

Send your question here to claim the channel.

Remember:
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>.
• Type the command .close to free the channel when you're done.
• 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.

crimson sedge
cedar kilnBOT
crimson sedge
#

guys can somebody explain to me how this was simplified?

pallid arrow
#

Change tan(x) to sin(x) / cos(x)

crimson sedge
#

then ?

#

im just really lost on how was this simplified