#help-10

1 messages · Page 579 of 1

knotty crow
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x = rcos(t)
y = rsin(t)

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but it's given in that form? I don't see equation here

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like you mean x = 4cos(t) and y = 5sin(t) ?

timid saddle
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ya, I tried to convert by solving for t

knotty crow
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so u see cos(t) = x/4 and sin(t) = y/5

timid saddle
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and then plugging it in

knotty crow
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use Pythagorean Identity

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sin^2(t) + cos^2(t) = 1

timid saddle
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can i get another hint?

knotty crow
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plug values of cos(t) (it's x/4) and sin(t) (it's y/5) into this equation

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then you'll get rid of t

timid saddle
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oh right its just the equation of the circle. right

knotty crow
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close to the circle but not, it's an ellipse

timid saddle
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right not a perfect circle cuz radius isn't the same throughout

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so equation is just (x/4)^2 + (y/5)^2 = 1

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thanks again.

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.close

obtuse pebbleBOT
#
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raw spade
#

How tf do you allign a split to the left of the page?

raw spade
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Like I want to be abled to align everything to the left, however the split wants to chill in the center

wooden cipher
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Maybe try \newline?

pseudo swift
raw spade
pseudo swift
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the purple also doesn't help tbh

raw spade
wooden cipher
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I didnt work?

raw spade
pseudo swift
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you can enclose the code inside ```latex ```

wooden cipher
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Aw shucks

raw spade
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\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{array}
\usepackage{fullpage}
\usepackage[utf8]{inputenc}
\setlength\parindent{0pt}
\begin{document}
\large
\textbf{Assingment 3: Math 3202}
\normalsize
\flushleft{

  1. \begin{equation*}
    \nabla \times F=\left|\begin{array}{ccc}e_{1} & e_{2} & e_{3} \ \frac{\partial}{\partial x} & \frac{\partial}{\partial y} & \frac{\partial}{\partial z} \ \sin y & x \cos y+\cos z & -y \sin z\end{array}\right|=\langle-\sin z+\sin z, 0, \cos y-\cos y\rangle=\langle 0,0,0\rangle
    \end{equation*}
    Thus, $F$ is conservative
    \begin{equation*}
    \frac{\partial \phi}{\partial y}=x \cos y+\cos z \Rightarrow \phi=x \sin y+y \cos z+f(x, z) \Rightarrow \frac{\partial \phi}{\partial x}=\sin y+\frac{\partial f}{\partial x}, \frac{\partial \phi}{\partial z}=-y \sin z+\frac{\partial f}{\partial z}
    \end{equation*}
    Thus, $\phi=x \sin y+y \cos z$}
    \begin{equation*}
    \begin{split}
    &r(0)=\langle 0,0,0\rangle \text {, and } r(1)=\langle\ 1, \frac{\pi}{2},\pi \rangle \
    &\int_{c} F \cdot d r=\phi(r(1))-\phi(r(0))= 1-\frac{\pi}{2}
    \end{split}
    \end{equation*}
    \end{document}
warm shaleBOT
#

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pseudo swift
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i mean i don't want to see it compiled

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just put your code inside `` and ``

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it will be less of a mess

raw spade
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‘ ‘ \documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{array}
\usepackage{fullpage}
\usepackage[utf8]{inputenc}
\setlength\parindent{0pt}
\begin{document}
\large
\textbf{Assingment 3: Math 3202}
\normalsize
\flushleft{

  1. \begin{equation*}
    \nabla \times F=\left|\begin{array}{ccc}e_{1} & e_{2} & e_{3} \ \frac{\partial}{\partial x} & \frac{\partial}{\partial y} & \frac{\partial}{\partial z} \ \sin y & x \cos y+\cos z & -y \sin z\end{array}\right|=\langle-\sin z+\sin z, 0, \cos y-\cos y\rangle=\langle 0,0,0\rangle
    \end{equation*}
    Thus, $F$ is conservative
    \begin{equation*}
    \frac{\partial \phi}{\partial y}=x \cos y+\cos z \Rightarrow \phi=x \sin y+y \cos z+f(x, z) \Rightarrow \frac{\partial \phi}{\partial x}=\sin y+\frac{\partial f}{\partial x}, \frac{\partial \phi}{\partial z}=-y \sin z+\frac{\partial f}{\partial z}
    \end{equation*}
    Thus, $\phi=x \sin y+y \cos z$}
    \begin{equation*}
    \begin{split}
    &r(0)=\langle 0,0,0\rangle \text {, and } r(1)=\langle\ 1, \frac{\pi}{2},\pi \rangle \
    &\int_{c} F \cdot d r=\phi(r(1))-\phi(r(0))= 1-\frac{\pi}{2}
    \end{split}
    \end{equation*}
    \end{document} ‘ ‘
warm shaleBOT
#

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pseudo swift
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just post your file maybe

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that's easy at least

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and discord colours it by default

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and no weird discord formatting shenanigans

raw spade
pseudo swift
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ah

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ok well just use my backticks instead of the weird backticks you found

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that'll do

pseudo swift
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or here ``

raw spade
#

`` \documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{array}
\usepackage{fullpage}
\usepackage[utf8]{inputenc}
\setlength\parindent{0pt}
\begin{document}
\large
\textbf{Assingment 3: Math 3202}
\normalsize
\flushleft{

  1. \begin{equation*}
    \nabla \times F=\left|\begin{array}{ccc}e_{1} & e_{2} & e_{3} \ \frac{\partial}{\partial x} & \frac{\partial}{\partial y} & \frac{\partial}{\partial z} \ \sin y & x \cos y+\cos z & -y \sin z\end{array}\right|=\langle-\sin z+\sin z, 0, \cos y-\cos y\rangle=\langle 0,0,0\rangle
    \end{equation*}
    Thus, $F$ is conservative
    \begin{equation*}
    \frac{\partial \phi}{\partial y}=x \cos y+\cos z \Rightarrow \phi=x \sin y+y \cos z+f(x, z) \Rightarrow \frac{\partial \phi}{\partial x}=\sin y+\frac{\partial f}{\partial x}, \frac{\partial \phi}{\partial z}=-y \sin z+\frac{\partial f}{\partial z}
    \end{equation*}
    Thus, $\phi=x \sin y+y \cos z$}
    \begin{equation*}
    \begin{split}
    &r(0)=\langle 0,0,0\rangle \text {, and } r(1)=\langle\ 1, \frac{\pi}{2},\pi \rangle \
    &\int_{c} F \cdot d r=\phi(r(1))-\phi(r(0))= 1-\frac{\pi}{2}
    \end{split}
    \end{equation*}
    \end{document}``
warm shaleBOT
#

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pseudo swift
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uh wat

raw spade
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I’ll try again

pseudo swift
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``

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ok let's do some backtick passing again

raw spade
#

`` \documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{array}
\usepackage{fullpage}
\usepackage[utf8]{inputenc}
\setlength\parindent{0pt}
\begin{document}
\large
\textbf{Assingment 3: Math 3202}
\normalsize
\flushleft{

  1. \begin{equation*}
    \nabla \times F=\left|\begin{array}{ccc}e_{1} & e_{2} & e_{3} \ \frac{\partial}{\partial x} & \frac{\partial}{\partial y} & \frac{\partial}{\partial z} \ \sin y & x \cos y+\cos z & -y \sin z\end{array}\right|=\langle-\sin z+\sin z, 0, \cos y-\cos y\rangle=\langle 0,0,0\rangle
    \end{equation*}
    Thus, $F$ is conservative
    \begin{equation*}
    \frac{\partial \phi}{\partial y}=x \cos y+\cos z \Rightarrow \phi=x \sin y+y \cos z+f(x, z) \Rightarrow \frac{\partial \phi}{\partial x}=\sin y+\frac{\partial f}{\partial x}, \frac{\partial \phi}{\partial z}=-y \sin z+\frac{\partial f}{\partial z}
    \end{equation*}
    Thus, $\phi=x \sin y+y \cos z$}
    \begin{equation*}
    \begin{split}
    &r(0)=\langle 0,0,0\rangle \text {, and } r(1)=\langle\ 1, \frac{\pi}{2},\pi \rangle \
    &\int_{c} F \cdot d r=\phi(r(1))-\phi(r(0))= 1-\frac{\pi}{2}
    \end{split}
    \end{equation*}
    \end{document}``
warm shaleBOT
#

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pseudo swift
#

ok cool

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uh so what do you want aligned again?

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the phi = stuff with the rest?

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at the bottom I mean

raw spade
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For some reason /flushleft did not work

pseudo swift
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ah I found something

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@raw spade

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googling for "math display mode left aligned"

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there's an flalign environment in amsmath which flushes equations to the left

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tldr

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but you should probably read to get a code example

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or here's the one you want

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\begin{flalign*}
    r(0)&=\langle 0,0,0\rangle \text {, and } r(1)=\langle\ 1, \frac{\pi}{2},\pi \rangle &\\
\int_{c} F \cdot d r&=\phi(r(1))-\phi(r(0))= 1-\frac{\pi}{2}&
\end{flalign*}
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the & allow you to specify which parts should be at the same level vertically

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ie all the parts at the level of the 1st & on different lines should be aligned

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same if there are multiple &

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the ending & (at the end of the line) seems to be really important for flalign (according to the post)

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in general I prefer align vs equation tbh

raw spade
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Oh shit it works. Thank you

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How do I close this thing?

pseudo swift
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.close

raw spade
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Thanks

#

.close

obtuse pebbleBOT
#
Channel closed

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timid silo
#

not sure where to go after i equal it to 0

obtuse pebbleBOT
timid silo
#

im at cos(3z) = 1/2

willow ravine
#

Do you know special right triangles?

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Specifically you’ll need the 30-60-90 one

timid silo
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yes i do

willow ravine
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So setup the 30-60-90 triangle, assign the appropriate side lengths, and pick which angle has cos(x) = 1/2

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Set whatever you decide x is = 3z to solve for z

timid silo
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could u draw it out for me

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im having a hard time understanding

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this is how they did it

fierce lagoon
willow ravine
#

You can take arccos

timid silo
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ohh

knotty crow
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btw it's weird question since that function is continuous I think?

willow ravine
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No the function is discontinuous at some points

knotty crow
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how we can talk about discontinuities at the point which are not in the domain

fierce lagoon
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That function isn't continuous

willow ravine
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Cos(3z) = 1/2

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Is in the domain

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Cosine exists between [-1, 1]

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1/2 is inside of that

knotty crow
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not really, for these values h(z) isn't defined, we can't divide by zero, so?

fierce lagoon
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It'll be asymptotic

knotty crow
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also you'd say 1/x isn't continuous?

fierce lagoon
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That is discontinuous

willow ravine
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That’s what we are trying to find, where it is discontinuous at.

fierce lagoon
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1/x isn't continuous since it has a vertical asymptote

willow ravine
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Modus, the question doesn’t state it is continuous. He is trying to find where it is discontinuous.

fierce lagoon
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It's literally discontinuous: look at the graph

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Note that the domain of where we're looking for discontinuities isn't restricted

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It's gonna contain every discontinuity

knotty crow
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My book says:
Function is continuous if it's continuous at each point of its domain.

timid silo
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is there an online graphing calc

tardy epoch
fierce lagoon
knotty crow
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how?

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u can divide by 0?

fierce lagoon
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It never specified any restrictions

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It's gonna default to -infinity by infinity

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Within that set of all real numebrs, there will be some that will result in discontinuities

knotty crow
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if you solve equation: (x^2 - x)/x = 0 you treat 0 as the solution because domain isn't given?

fierce lagoon
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0 is gonna be a discontinuity lol

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0 is within the set of all real numbers

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I don't know what you're trying to argue here

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And it is discontinuous within the all-reals domain

zenith raft
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I think the problem here is that under the definitions mathematicians use, things like 1/x and 1/(2-4cos(2x)) are continuous, but the problem does not want you to use those definitions (unfortunately???)

knotty crow
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My maths book, Wikipedia and other sites on the internet says that theorem is true, we analyze only domain, I'm trying to decide what's the right way

zenith raft
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that is the "right" way

fierce lagoon
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That is the right way

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But look at the problem

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It doesn't specify any domain

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So it's a default assumption to be all reals

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-infinity to infinity

zenith raft
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well I'd say h is not discontinuous anywhere, but I know that's not what they want

fierce lagoon
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No (in agreement lol)

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They wanna find places where h(z) is discontinuous for $z\in\mathbb{R}$

warm shaleBOT
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Umbraleviathan

zenith raft
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there is no meaning of continuous or discontinuous where a function isn't defined

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or at least...

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no one really cares about that lol

fierce lagoon
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I mean at this point it's going to a discussion beyond David's level I think

zenith raft
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yea I agree

fierce lagoon
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It assumes all reals

zenith raft
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but I just wanted to say, I think that's the source of the argument

willow ravine
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Modus, no one is trying to say this function is continuous. The problem literally says “find where the DISCONTINUITY is”

zenith raft
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well I agree with the point that it's not discontinuous anywhere under formal definitions

willow ravine
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Look the function is discontinuous at (pi/3) + 2pi n

timid silo
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isn't it just discounious when 2-4cos(3z)=0 ?
so solve for z, and then generate a set using ±a where a is the period of the function.

fierce lagoon
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Yeah

willow ravine
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yes

fierce lagoon
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But like

knotty crow
fierce lagoon
#

THE DOMAIN IS ALL RWALS DKSSJJDOS

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You assume all reals

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This. Is. What. I've. Been. Saying bdjajhdkslekejdjf

willow ravine
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The discontinuity happens when cos(3z) = 1/2

fierce lagoon
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Which is in the all reals set

willow ravine
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1/2 is inside of the domain of cosine

knotty crow
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OK GUYS YOU'RE RIGHT, JUST STOP IT DOESN'T HELP ANYONE PLEASE

zenith raft
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if the domain is all reals, then h(5pi/9) must be something you can evaluate

willow ravine
zenith raft
timid silo
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what do i do after i equal it to zero and solve for z

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math help chat drama? ill get my popcorn

willow ravine
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You just add 2pi*n

timid silo
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z = .349

willow ravine
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To z

timid silo
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why do i add? and whats n?

willow ravine
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n is an integer

timid silo
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the period of the equation (when it repeats)

willow ravine
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It repeats every 2pi

timid silo
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well its cos(3z)

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shouldnt i add the 2pi*n before i divide by 3

willow ravine
#

You know, I’m just gonna pop out of this chat. I hope Modus can convince you this equation is continuous and the problem is wrong by trying to make you find its discontinuity.👍🏼

timid silo
#

ight, david you okay with me to take over?

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yeah sure

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so just a quick review

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this 1/x type equation is discontinous when the bottom of the fraction is equal to 0

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(because your deviding by zero)

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yes

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so the point that the function will be discounious is when 2-4cos(3z) = 0

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yes

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i got z = .349

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@timid silo

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yeah one sec im verifing

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we get cos(3x)=1/2

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yes

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we take the arccos of both sides

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3x = cos^-1(1/2)

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yep

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now add 2pi * n?

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can u explain why 2pi * n?

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3x = pi/3

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x = pi/9

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huh

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hold on wait im missing something

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we should get 2

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2 points?

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yes

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how come?

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take a look at desmos

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cause cos(3x)=1/2 has 2 answers

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(well 2 answers in 1 period)

knotty crow
#

Generally solution to the equation:
$$\cos x = a$$
where $-1 \leq a \leq 1$, is:
$$x =\arccos a + 2\pi n \vee x = -\arccos a + 2\pi n$$
$$n \in \mathbb{Z}$$

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this is because cosine is even function (cos(x) = cos(-x))

timid silo
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oh yeah forgot about that lol

knotty crow
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and 2 pi n is because period of cosine is 2pi

timid silo
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yes

warm shaleBOT
timid silo
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i thought 2pi was the whole circle

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yep, that general for cos(x) not cos(3x)

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then again if we define x = 3z and repalce x

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Generally solution to the equation:
$$\cos 3z = a$$
where $-1 \leq a \leq 1$, is:
$$3z =\arccos a + 2\pi n \vee x = -\arccos a + 2\pi n$$
$$n \in \mathbb{Z}$$

warm shaleBOT
#

aspwil

knotty crow
timid silo
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so when using the unit circle to solve

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do i always use 2pi * n?

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yes, because
cos(x) = cos(x+2pi*1) = cos(x+2pi*2) = cos(x+2pi*3) = cos(x+2pi*4) ...

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ooo ok

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so cos(x) = cos(x+2pi*n) for any n in integers

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$\cos(x)=\cos(x+2\pi n)$

warm shaleBOT
#

aspwil

timid silo
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and exstended is

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$\cos(ax)=\cos(ax+\frac{2\pi n}{a})$

warm shaleBOT
#

aspwil

timid silo
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im writing notes rn so what is the reason i should put for adding 2pi * n

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like a quick explanation

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something like

"when we add 2pi to the cos we get the same answer as before [cos(x) = cos(x+2pi)]
therefor if we say cos(x) = 2 that means that cos(x+2pi) = 2,
and for any integer n we choose, cos(x+2pin) = 2.
 therefor if we take the cos^-1 of both sides we get x+2pin = cos^-1(2),
 so when solving for x we need to take into account this 2pin, thus leaving us with x = cos^-1(2)-2pin"```
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so do we only do that when we take the cos^-1 of both sides?

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and to push it a little further -2pin can be changed to +2pin because n is all integers, (... 3, 2, 1, 0, -1, -2, -3...) so if we make it negative we still get all the integers.
meaning that n = -n
and thus
-2*pi*n = -2*pi*-n = 2*pi*n

#

ooo ok thank u

timid silo
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so what we should get is

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$3z = {\frac{\pi}{3},\frac{5\pi}{3}}+2\pi n\z = {\frac{\pi}{9},\frac{5\pi}{9}}+\frac{2\pi n}{3}$

warm shaleBOT
#

aspwil

timid silo
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because

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how does 0.349 turn into pi/9

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$\cos(3z)=\frac{1}{2}\ \cos(3z+2\pi n)=\frac{1}{2}\ 3z+2\pi n=\cos^{-1}(\frac{1}{2})\3z = {\frac{\pi}{3},\frac{5\pi}{3}}+2\pi n\z = {\frac{\pi}{9},\frac{5\pi}{9}}+\frac{2\pi n}{3} $

#

$\cos(3z)=\frac{1}{2}\ \cos(3z+2\pi n)=\frac{1}{2}\ 3z+2\pi n=\cos^{-1}(\frac{1}{2})\3z = {\frac{\pi}{3},\frac{5\pi}{3}}+2\pi n\z = {\frac{\pi}{9},\frac{5\pi}{9}}+\frac{2\pi n}{3}$

warm shaleBOT
#

aspwil

timid silo
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does that explain everything you need?

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or is there anything your still unclear about?

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(if you end up needing more help dm me, and ill come back)

obtuse pebbleBOT
#

@timid silo Has your question been resolved?

timid silo
#

@timid silo thank u i will

obtuse pebbleBOT
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crisp dune
#

What does finding the avg value of a function do ?

obtuse pebbleBOT
#

@crisp dune Has your question been resolved?

willow ravine
#

Do you have a picture of the question problem?

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

sage lintel
#

How can I eliminate the parameter in these parametric equations
x = 3-cos2t
y = 1 + sin2t

I solved for t in the first equation and ended up with t = arccos(3-x)/2
I then substituted that in the second equation and ended up with 1 + sqrt(1 - (3 - x)^2)
However my professor said the equation should be an ellipse, and mine looks like a circle

short zodiac
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Use sin^2(2t) +cos^2(2t)=1

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By expressing sin(2t) and cos(2t) in terms of x and y

sage lintel
#

ok i'll try that

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however is there a reason my method doesn't work?

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idk if I made some erorr in my simplification

short zodiac
#

Yours is a more complicated way of expressing it, especially the square root can lead to loss of some of the curve values

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Better to do it simply

sage lintel
#

gotcha, just to check does the answer turn out to be 1 = (y-1)^2 + (3-x)^2

#

thank you!

#

.close

obtuse pebbleBOT
#
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sage lintel
#

.reopen

obtuse pebbleBOT
#

short zodiac
#

In that case you have no alternative but to express sin or cos in terms of the other

#

This identity can't be used for different arguments

#

It'll depend on the qn

sage lintel
#

.close

obtuse pebbleBOT
#
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timid silo
#

Very simple but hard for me to understand. X/x=0 because they cancel (basic algebra). If x=7 then x/x=1. Why do we count it as 0 and not 0 or 1?

cursive jolt
#

X/x=0 because they cancel
?

willow ravine
#

x/x =1

valid crown
#

x-x = 0

willow ravine
#

X/X does not equal X-X

timid silo
#

I was taught xy/xy=0

#

but confused why it doesn’t =2

willow ravine
#

xy/xy does not equal 0

zenith raft
#

for any real number x other than 0, x/x = 1 because 1/x is defined to be the number that when multiplied by x, is equal to 1
and x/x is another way of writing x*(1/x)

timid silo
#

correct

timid silo
#

.close

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timid silo
#

not sure where to go after this

obtuse pebbleBOT
willow ravine
#

Cos2x =0

#

Solve for x

timid silo
#

2x = cos^-1(0)

willow ravine
#

There are two points where cosine is 0

#

Are you working with degrees or radians?

timid silo
#

radians

willow ravine
#

pi/2 and 3pi/2

timid silo
#

how?

willow ravine
#

Are the two points

timid silo
#

how do u get that

willow ravine
#

Look at radians column and cosine column

#

Also looking at the graph of cosine from 0 to 2pi

#

It hits the x-axis (equals 0) twice

timid silo
#

can i send u my work so far

#

@willow ravine

willow ravine
#

You may need to lessen your period on this one.

#

So let cos^-1(0) be equal to pi/2

#

And add just pi*n

timid silo
#

i thought cos(0) = pi/2

willow ravine
#

No

#

Cos(pi/2) = 0

#

And cos (3pi/2)= 0

#

Where before you only had one value from [0, 2pi] for x. In this case you have 2 values.

timid silo
#

ooo

willow ravine
#

So, since it only takes pi radians to get from pi/2 to 3pi/2

timid silo
#

do i do (2pi) - pi/2

#

to find the other value

willow ravine
#

You can

#

But that just gives 3pi/2

timid silo
#

what quadrant would the second solution be in

willow ravine
#

The solutions lie on the y-axis

#

Not a specific quadrant

#

Well hang on, it’s cos 2x

#

And you want 2x = pi/2

#

So x=pi/4

#

Is the first quadrant

#

And 2x = 3pi/2, x= 3pi/4

#

Is in the second quadrant

obtuse pebbleBOT
#

@timid silo Has your question been resolved?

timid silo
#

ohhh okay thank u sm

obtuse pebbleBOT
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willow ravine
obtuse pebbleBOT
willow ravine
#

Complex variables: this is what I got so far:

#

Is this correct so far?

#

Also, is the easiest way to o go about this is convert them all into cos(t) + isin(t)?

wooden cipher
#

Oh my god ok

#

I think i can handle this one

#

If my internet works >:(

#

Split the integral to its separate terms

#

For example the first terms becomes
4/i [e^4it] evaluated from 0 to 2pi

willow ravine
#

Okay. I’ll try to do all of them

wooden cipher
#

So 4/i[e^8pi(i)-1] which is
4/i[1-1]=0

brave bramble
#

You were correct Poisoned, that the first two terms are just zero because Cauchy.

#

The last term is the one that throws a fit

willow ravine
brave bramble
#

Avoid expanding it. I'm pretty sure that, with that sub, it just becomes cos³θ

willow ravine
#

This?

brave bramble
#

Oh wait, the last term is 0 too, isn't it? Haha

#

Cool result

willow ravine
#

I saw somewhere that any z^x is 0 unless x=-1 hence the 3/z term is the only one but I can’t use that if I don’t understand that enough to explain it to my professor.

#

Apparently 1/x integrated is 2pi*i

#

Which would be exactly 6pii/2pii

brave bramble
#

You know Cauchy-Goursat, that any closed integral around an analytic region is 0?

willow ravine
#

Yes I knew that for the first two terms

#

But the 1/z^3

#

I couldn’t use that for it

brave bramble
#

That's enough to say, for positive n, that zⁿ integrates to 0

willow ravine
#

But the 3/z and 3/(z^3)

#

Was stumping me

brave bramble
#

We also have that any function with an anti-derivative integrates to 0

#

That's enough to kill 3/z³

willow ravine
#

1/z has an antiderivative

#

But it’s not zero

brave bramble
#

It does not!

willow ravine
#

Ln(z)

#

?

brave bramble
#

For any contour that doesn't include the negative x-axis, I would agree with that

#

Actually, no I don't think that's even true. I need to remind myself why no version of ln is an anti-derivative for 1/z

willow ravine
#

Also did I do the second one on the right side of my original post correctly?

brave bramble
#

The big deal is that every polynomial term and inverse polynomial term integrates to 0, leaving 3/z

willow ravine
brave bramble
#

That's essentially the residue theorem, that it's enough to find the constant on 1/z

willow ravine
#

The 2pi*i always confuses me

#

Do I add another and cancel them out to get -1/3?

brave bramble
#

I admit I'm bad with Cauchy's formula

willow ravine
#

Maybe Riemann or Ahoron can help

brave bramble
#

I feel you've lost a πi in the numerator somewhere

#

Residue is -1/3

willow ravine
#

a pii? Not 2pii

brave bramble
#

Right, a 2πi

#

Should cancel the denominator leaving -1/3

willow ravine
#

Awesome!

#

Onto the next 🥲

#

.close

obtuse pebbleBOT
#
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high snow
#

How can I solve this?

obtuse pebbleBOT
grizzled shore
#

what do you know about the GCF?

#

@high snow

high snow
#

You can use prime factorization on both numbers and multiply the common factors to find the gcf

ruby shoal
#

How bout that LCM

grizzled shore
#

more importantly, it means a and b are multiples of 12

#

yeah?

#

a = 12x
b = 12y

high snow
#

Yea

grizzled shore
#

huh

#

oh

#

$\frac{1}{12x} + \frac{1}{12y}=\frac{1}{12}\left(\frac{1}{x}+\frac{1}{y}\right)=\frac{x+y}{12xy}, 12xy = 144 xy = 12$ find $xy = 12$ where x and y has no common factors

wooden cipher
#

Heres a little tidbit GCF×LCM is the product of your two numbers

#

Still do have to satisfy the gcf and lcm separately tho

grizzled shore
#

the only things with x y is that they cant have any common factors except 1

warm shaleBOT
#

Frosst

obtuse pebbleBOT
#

@high snow Has your question been resolved?

grizzled shore
#

if they had another common factor

#

then HCF wouldn't be 12

#

it'd be 12*whatever their common factor was

#

ie. if x = 2, y = 6, a = 24, b = 72, their HCF would be 12 * 2 = 24, and LCM = 144

obtuse pebbleBOT
#
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obtuse pebbleBOT
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compact gate
#

When integrating by parts, we define u and dv. Then we differentiate u and integrate dv to find v. This is all well and good. The part that confuses me is why we leave out the constant when integrating dv. Could someone help me understand why we're allowed to do this?

tardy epoch
#

decent explanation

compact gate
#

thanks

#

exactly what I was looking for

#

.close

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chilly veldt
#

Why would this be wrong

obtuse pebbleBOT
tardy epoch
#

take a derivative and see if you get the integrand

obtuse pebbleBOT
#

@chilly veldt Has your question been resolved?

chilly veldt
#

You can only pull constants out

obtuse pebbleBOT
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obtuse pebbleBOT
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timid silo
#

Sos

obtuse pebbleBOT
timid silo
#

Ans for (c)

#

Why can't I

  1. Translate curve 1 unit in positive x direction
  2. Reflect curve about y axis
    3.scale factor of 3 parallel to y axis
#

Is this wrong? Whats the right way?

#

My way^

#

Please help idk how anymore

obtuse pebbleBOT
#

@timid silo Has your question been resolved?

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hexed agate
#

Why in the positive direction of x?

obtuse pebbleBOT
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pulsar raft
#

I have problems understanding this proof. How come that the inequality (1) holds? Is it because we have defined ${x_n}\rightarrow d$ and therefore the two terms in the sequence $x_n+x_m$ will both be very close to $d$, giving us something like $(\frac{d+d}{2})^2\geq d^2$

And for (2), how can we see that this is a Cauchy sequence? Do we have to take the square root of the expression and see that $0\leq x_n-x_m\leq\epsilon$?

warm shaleBOT
#

simonpetri

obtuse pebbleBOT
#

@pulsar raft Has your question been resolved?

kind hawk
#

y=1/2 (x_n+x_m) is in K because K is convex, so norm(y)>= inf{all norms of K}=d

#

for the second we know that 2(norm(x_n)^2+norm(x_m)^2)-4d^2->2(d^2+d^2)-4d^2=0

#

so by the squeeze theorem norm(x_n-x_m) also has to go to 0

pulsar raft
#

So for (1), By convexity, y=1/2(x_n+x_m) is in K and because d=inf{all norms of K} we must have that norm(y) must either be d or some norm greater than d.

kind hawk
#

yes

pulsar raft
#

And if i understand correctly, for (2) we have that as x_n and a_m will both eventually be equal to d somewhere in the sequence. Then norm(x_n-x_m)^2 will be squeezed in between zero and zero eventually in the sequence.

kind hawk
#

well not equal to d

#

but in the limit equal

pulsar raft
#

very close to d then 🙂

kind hawk
#

yes

#

so we have 0<= norm(x_n-x_m) <= (something tiny)

#

so the middle has to go to 0

pulsar raft
#

Yes I see it now. Thank you very much. I really got lost somewhere and could not figure out what was happening.

#

.close

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#
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obtuse pebbleBOT
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solar elm
#

can anyone help me with this

obtuse pebbleBOT
#

@solar elm Has your question been resolved?

solar elm
#

also this

2. During a month with 30 days, a baseball team plays at least one game a
day, but no more than 45 games. Show that there must be a period of some
number of consecutive days during which the team must play exactly 14
games.
Solution: Let aj be the number of games played on or before the j-th day of
the month. Then
a1 , a2 ,..., a30 is an increasing sequence of distinct positive integers, with 1 ≤ aj
≤ 45. Moreover, a1 + 14, a2 + 14,..., a30 + 14 is also an increasing sequence of
distinct positive integers, with 15 ≤ aj + 14 ≤ 59.
The 60 positive integers a 1 , a2 ,..., a30 , a1 + 14, a2 + 14,..., a30 + 14 are all less
than or
equal to 59. Hence, by the pigeonhole principle two of these integers are
equal. Because the
integers aj , j = 1, 2,..., 30 are all distinct and the integers a j + 14, j = 1, 2,...,
30 are all distinct, there must be indices i and j with ai = aj + 14. This means
that exactly 14 games were played from day j + 1 to day i.
royal basin
#

that's... the solution to the same problem

obtuse pebbleBOT
#

@solar elm Has your question been resolved?

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subtle adder
#

The digits 2, 3, 4, 7 and 8 will be put in random order to make a positive five-digit integer. What is the probability that the resulting integer will be divisible by 11? Express your answer as a common fraction.

pseudo swift
#

that would probably help

subtle adder
#

the only divisiblity rule of 11 i know is adding the alternate digits and finding the difference between them

#

i got the total possibles numbers

#

$5! = 120$

warm shaleBOT
#

☙ Kiwwi ❧

subtle adder
#

possibilities

pseudo swift
#

yeah you got 120 possible orderings of you digits

#

now you know you'll have pretty much 2 types of digits when considering divisbility by 11

#

you'll have the ones counted positively and the ones counted negatively

#

let's say I fix the two digits which are counted negatively

#

how can you check such an arrangement could work ?

subtle adder
#

not sure

#

do you mean checking if the number is divisible or not?

pseudo swift
#

we want to see which choices give us numbers divisble by 11

subtle adder
#

i am aware of how to do that, but i don't now how to count the number of possibilities that gives a number divisble by 11

pseudo swift
#

so yeah if I give you the two "negative" numbers, the three "positive" numbers are already chosen

#

so you can check divisibility this way

subtle adder
#

i don't understand

pseudo swift
#

at what point

subtle adder
#

fixing numbers

#

i'm sorry, but could you do the problem in its entirety? I'm not able to understand the idea of fixing numbers

pseudo swift
#

I'm getting to it yeah

#

the point is, the choice of the two negative digits forces what the 3 positive digits have to be

#

now, how many ways are there to choose 2 negative digits (among the 5 we got) ?

subtle adder
#

5C2

pseudo swift
#

yeah so 10

subtle adder
#

10

pseudo swift
#

the number of ways you can choose the two negative digits, gives you the number of ways of splitting the 5 digits among the two classes positive and negative

#

it doesn't give you all the orderings possible

#

(you still have to account for them inside the positive and negative classes)

#

but divisibility by 11 doesn't care about those internal orderings

#

so that's why I only looked at splitting positive/negative

pseudo swift
#

take all the choices of 2 negative digits possible

#

and check if you got divisibility by 11 for each choice

subtle adder
#

how?

pseudo swift
#

how, like the big picture ?

#

or how to check divisibility by 11 ?

#

I could do one example to show you

subtle adder
#

please do so

pseudo swift
#

our set of digits we take from is 2, 3, 4, 7 and 8

#

let's say the negative digits are 2 and 3

#

then the positive digits are 4, 7, 8 right ?

#

(and then the idea is to repeat that argument for every possible choice of negative digits)

subtle adder
#

ah

#

thank you

#

i understand now

#

.close

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#
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fluid snow
#

$$\frac{1}{\sqrt[3]{1} + \sqrt[3]{2} + \sqrt[3]{4}} + \frac{1}{\sqrt[3]{4} + \sqrt[3]{6} + \sqrt[3]{9}} + \frac{1}{\sqrt[3]{9} + \sqrt[3]{12} + \sqrt[3]{16}}$$
\
Find the sum.

fluid snow
#

Hints only please

#

I noticed that they are all of the form (a + b)²

high lily
#

but they're not

warm shaleBOT
high lily
#

no

fluid snow
#

But the problem is the 3rd root

high lily
#

those equations you wrote are all false

fluid snow
#

uh, what am i doing lol

high lily
#

consider factorisation for a difference of two cubes

#

the denominators are in the form a^2 + ab + b^2

fluid snow
#

or does it turn into a difference bc of reciprocal

high lily
#

i'd recommend looking it up so you can see it more clearly

regal coral
#

maybe simplifying them would give another perspective?

fluid snow
fluid snow
warm shaleBOT
regal coral
#

the denominator is clearly your problem, you could try removing the radical

fluid snow
#

oh, so the latter bracket

#

is what's in the denominators

#

so I should multiply by (a-b)/(a - b) each frac

high lily
#

yes, multiply numerator and denominator by (a-b)

regal coral
#

you can also look up for how to evaluate radicals thingy

fluid snow
#

.close

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#
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worthy cargo
#

for some reason i can't find the factorizatjon of two perfect squares what is it?

worthy cargo
#

a^2 + b^2

nocturne minnow
#

Because that can't be factored

#

a^2 - b^2 is possible but not a^2 + b^2

nocturne sun
#

I mean you can say (a + b)^2 - 2ab but that's not really factoring I guess

worthy cargo
#

oh i see i was thinking of ^

#

but i also get what you mean

#

alright thanks

#

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hasty linden
#

quick question

obtuse pebbleBOT
hasty linden
#

on the second line

#

did we just divide the demoniator by n

#

dont worry about the following steps

pale mortar
hasty linden
#

is that allowed

#

cause if you take out 1/n it becomes 1 +1/n

pale mortar
#

Well

#

What happens there is that the limit is multiply by (1/n)/(1/n)

#

So the numerator is going outside and the denominator to the denominator

obtuse pebbleBOT
#

@hasty linden Has your question been resolved?

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proven monolith
#

imma need some help on this equation

obtuse pebbleBOT
proven monolith
#

x² - 4 + (2x + 5) (x + 2) = 0

#

solve by factoring

high lily
#

what have you tried

proven monolith
#

I tried to look for something to factorise with

velvet sundial
#

dismantle the x2 - 4

proven monolith
#

thats what i did but i don't know how to continue

high lily
#

were you successful in factorising x^2-4

proven monolith
#

no thats the thing

#

I dismantled x² - 4

velvet sundial
high lily
#

dismantled?

proven monolith
#

x.x - 2.2 + (2x + 5) (x + 2) = 0

high lily
#

that doesn't really help

#

x^2 - 4 is a difference of two squares

proven monolith
#

mhm

high lily
#

there's a factorisation identity for that

simple cradle
#

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

warm shaleBOT
#

yüce tengri

high lily
#

no

proven monolith
#

isn't it the 3rd one?

#

oh

velvet sundial
#

WHAT NO

proven monolith
#

i'm kind of confused rn

high lily
#

ignore yuce

proven monolith
#

alright

high lily
#

x^2 - 4 is a difference of two squares
there's a factorisation identity for that

#

if you don't know it, look up difference of two squares

proven monolith
#

I might know it but I don't study in english

#

gimme a sec

#

oh that the 3rd identity

#

Yeah can I just use that?

#

Literally just solve the equation

high lily
#

I don't know how the list of identities you're using is numbered

proven monolith
#

the 3rd one is the difference of two squares

#

We number it that way

high lily
#

calling it 3rd means nothing to me

proven monolith
#

fair enough I thought you guys would call it the same thing

high lily
#

so yeh, you have a difference of
two squares and you can use the identity for that

proven monolith
#

yeah I'll do it rn, I'll show you my answer in a bit

#

(x +2) (x -2) + (2x + 5) (x + 2) = 0

#

factorise with (x+2)

#

i got

velvet sundial
#

yeah that's right

proven monolith
#

(x +2) (x - 2 +2x + 5) = 0

#

(x + 2) (x + 3) = 0

#

So now I just use the zero factor thingy

#

right

#

either x + 2 = 0 or x + 3 = 0

high lily
#

messed up simplification

proven monolith
#

oh wait

#

yeah bruh

#

(x + 2) (3x + 3) = 0

#

mb

velvet sundial
#

wait

#

3x + 3?

proven monolith
#

i think so

velvet sundial
#

where do you get the extra 3

high lily
#

3x+3 is fine

velvet sundial
#

oh yeah

proven monolith
#

2x + x

#
  • 2 - 5
#

wait no

#

5 - 2

#

alright i think i carry on thanks for the help!

#

.close

obtuse pebbleBOT
#
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hazy vine
#

3+9/5+27/25+81/125+243/625+...

obtuse pebbleBOT
nocturne sun
warm shaleBOT
hazy vine
#

nop

nocturne sun
#

hm?

hazy vine
#

my question is literally what I typed

#

but I guess I could find the sequence and write it like that

nocturne sun
#

alright so it's a geometric series

#

$\sum_{n=1}^{\infty} \frac{3^n}{5^{n - 1}} = \sum_{n=1}^{\infty} 5 (\frac35)^n$

#

hm wait I may have done it wrong

#

gimme a sec

#

yeah let me edit

warm shaleBOT
hazy vine
#

oh alright yeah I got it I think

#

give me 5 minutes plz

nocturne sun
#

alright

hazy vine
#

I'm doing it on paper

#

found 15/2

nocturne sun
#

yeah should be correct

hazy vine
#

thanks

#

.close

obtuse pebbleBOT
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lucid delta
#

Hey I'm stuck on a logic problem and I can't find any sources on how to convert from CNF to CCNF

obtuse pebbleBOT
#

@lucid delta Has your question been resolved?

obtuse pebbleBOT
#

@lucid delta Has your question been resolved?

obtuse pebbleBOT
#

@lucid delta Has your question been resolved?

obtuse pebbleBOT
#

@lucid delta Has your question been resolved?

willow ravine
#

Well I take that back. The false part that is.

#

It is always true if r is true though.

obtuse pebbleBOT
#

@lucid delta Has your question been resolved?

obtuse pebbleBOT
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tardy epoch
#

i see 4 vectors

#

two blue ones look like they could lie on the same line so one's a scalar multiple of the other

royal basin
#

what two vectors?

#

can you show the original problem exactly as it is stated?

tardy epoch
#

4x = 4|x| on [0,1]

#

C[0,1] is not the same as [0,1]

royal basin
#

ok right so

#

From what I was told, two vectors are only linearly dependent if they are parallel,

#

this works only if you're dealing with a vector space consisting of like... geometrically drawn vectors, as in those little arrow thingies

#

i.e. that visual image of linear independence holds only for R^2 and R^3

#

for this, they give you two functions and ask if the restrictions of these functions to [0,1] are linearly independent as elements of C[0,1].

#

by "the restrictions of these functions to [0,1]", i mean this:

obtuse pebbleBOT
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tardy epoch
#

no

obtuse pebbleBOT
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pulsar coral
#

can someone help me with this

obtuse pebbleBOT
pulsar coral
timid silo
pulsar coral
#

i got it

obtuse pebbleBOT
#

@pulsar coral Has your question been resolved?

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obtuse pebbleBOT
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@timid silo Has your question been resolved?

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timber osprey
#

Hi, my struggle continues with probability
Two 6sided dice are thrown continuously at the same time, until the multiplication of the resulting numbers from the 2 dice are odd
What's the probability of this ^ happening in the third try?

tardy epoch
#

Probably want to find the probability mass function for the products of the two dice

timber osprey
tardy epoch
#

P(X=1) = 1/36, etc.

#

X = product of the two numbers

timber osprey
tardy epoch
#

You probably have. Just called it something else

#

Unless you prove something about the symmetry or something and show that X has equal probability of being odd and even

timber osprey
short zodiac
#

Yes, I think this is correct

obtuse pebbleBOT
#

@timber osprey Has your question been resolved?

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stone rain
#

hello

obtuse pebbleBOT
stone rain
#

could someone help check if I did this question correctly

obtuse pebbleBOT
#

@stone rain Has your question been resolved?

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blissful seal
#

how can i solve this

obtuse pebbleBOT
cloud dove
#

you know that when x=0 that y=2

fickle turret
#

What have you tried so far?

cloud dove
#

try plugging in 0 for the exponents and see what happens

blissful seal
blissful seal
cloud dove
#

well, when you plug in 0 for x, you try to solve for f(0)

fickle turret
cloud dove
#

and see what matches up w/ the graph

#

from there, you should have a good idea where to go from that point

blissful seal
cloud dove
#

uh

#

its an exponential function?

#

dont know what else to really say

blissful seal
#

im really lost tbh

cloud dove
#

for starters, id do like

$f(0) = -2 * 3^0$

warm shaleBOT
cloud dove
#

and then keep doing this for a,b,c,d

#

and then see what you get

blissful seal
#

that would equal to -2

cloud dove
#

the graph has (0,2)

#

so which ones equal 2?

blissful seal
#

aha ok

cloud dove
#

then figure out which out of them is the correct one

#

you can try plugging x=1 to determine that then

blissful seal
#

thank you dude

cloud dove
#

nwnw

blissful seal
#

.close

obtuse pebbleBOT
#
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fickle turret
#

There are still two of them

cloud dove
#

to make sure you dont pick the wrong one out of the two

blissful seal
#

.reopen

obtuse pebbleBOT
#

blissful seal
cloud dove
#

yeah looking at the graph, it looks itd be (1,6)

blissful seal
#

wait wha

#

what did you do to make (1,6)

cloud dove
#

oh no i just looked at the graph lool

blissful seal
#

and how did 1,6 come up xD

cloud dove
#

but for b) if you do $f(1) = 2*(1/3)^1\rightarrow 2/3$

warm shaleBOT
cloud dove
#

which means that the graph should be going from 2-> 2/3

blissful seal
#

you lost me here

cloud dove
#

but in d) if you do $f(1) = 2*3^1\rightarrow 6$

warm shaleBOT
cloud dove
#

which means the graph would be increasing

blissful seal
#

ah yes

#

but if im looking at the graph isnt it 1,5 or am i mistaken

cloud dove
#

well it doesnt really matter

#

if it's (b) then it's going to lower values after 0

#

but if its (d) then its increasing after 0

#

and the graph given is increasing

#

are u following so far?

blissful seal
#

yes

cloud dove
#

good

#

now that should be clear now

blissful seal
#

it is thank you

#

Tbh

#

like every other question seem to be hard for me even though i studied

cloud dove
#

i wish you much luck

blissful seal
fickle turret
#

Maybe something to mention:
(1/3)^x = 3^(-x) which is just 3^x reflected on Y-axis

cloud dove
#

oh smart

blissful seal
#

did think of that

#

didnt*

#

Thank you both for your time

fickle turret
#

You're welcome l. Meek did the most

blissful seal
#

You both did great and made me understand it better

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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icy yacht
#

So I have a question. If dec 21 at 2020 at 6am was the last update of my app, what day would it be 5 updates evenly scattered from that day to the current day at 6am?

obtuse pebbleBOT
#

@icy yacht Has your question been resolved?

somber mural
#

your question doesn't make sense

icy yacht
#

Like I have an app on my phone that was installed on dec 21 2020 at 7pm and after that update, there’s 5 more after it. The last update of the 5 was yesterday at 7pm. My question is was for the 4 updates before yesterday’s one, if I evenly distributed it from yesterday to the other day (dec 21 2020) what would each month and day be for all 4?

obtuse pebbleBOT
#

@icy yacht Has your question been resolved?

obtuse pebbleBOT
#

@icy yacht Has your question been resolved?

obtuse pebbleBOT
#

@icy yacht Has your question been resolved?

icy yacht
#

What’s that?

obtuse pebbleBOT
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kindred silo
#

not sure how to do this at all

obtuse pebbleBOT
royal basin
#

are you familiar with things such as double-angle identities?

#

namely the one for sin(2x)

kindred silo
#

ive heard of such a thing

#

but im not too sure what it exactly is

royal basin
#

$\sin(2x) = 2\sin(x)\cos(x)$

warm shaleBOT
royal basin
#

does this ring any bells? or have you only heard wind of it

kindred silo
#

ah

#

yes ive seen this before

#

how would i use it?

royal basin
#

well notice that what you have here can be written as [2sin(pi/8)cos(pi/8)]^2

kindred silo
#

ohhh i see

#

thats neat

#

well ty

#

🙏

#

.close

obtuse pebbleBOT
#
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low halo
#

Natural numbers m, n, k when divided by 7 give the remainders 3, 5 and 1 respectively, then the number mk + n gives the remainder when divided by 7 ?

low halo
#

Sorry for posting so many times my internet breaks due to a storm

#

And the solution is 1 i mean the remainder

proven zephyr
#

so... what's the question?

low halo
#

Idk i have written all i was given

proven zephyr
#

you already got the answer

#

what do you need help with

pallid canyon
#

Are you looking for the remainder of mk + n when divided by 7?

low halo
#

Yea i cant figure out hot to get 1 basicaly

proven zephyr
#

oh ok

valid crown
#

(3×1 + 5)mod7

kind hawk
#

if you want to, write m=7x+3, n=7y+5 and k=7z+1, where x,y,z are some integers

#

then multiply out (7x+3)(7z+1)+(7y+5) and take the remainder when you divide it by 7

valid crown
#

altough good tactic

kind hawk
#

thanks

low halo
#

Yea its fine i get what he meant

kind hawk
#

but the great thing about remainders is that it doesn't matter if you first take remainders and then add/multiply or first add/multiply and after that take remainders

#

maybe if you are interested try proving that for yourself

valid crown
#

last thing to observe is any non 7×variable part adds up to 8

low halo
#

I got some other things i need to finish but tnx for clearing that up

#

Tnx for help

timid silo
kind hawk
#

well if they knew what modular arithmetic is then they wouldn't have asked I think

timid silo
#

then maybe we should explain modular arithmetic.

obtuse pebbleBOT
#

@low halo Has your question been resolved?

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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ivory flare
#

Hellooo I’m back. I tried to solve this and I have no idea what’s happening. I tried a math app but it gave me part of the answer and showed no steps. The correct answer is -3,4

ivory flare
pine sail
#

Where did you get the square root from exactly?

#

There shouldn't be one.

ivory flare
#

I tried to remove the square

pine sail
#

There are no squares?

ivory flare
#

And i thought getting a root would help🥲

#

9w²

pine sail
#

Yes but your square root is all over 9w^2 - 108

#

Infact you didn't do anything to the RHS

swift marsh
#

And just solve the resulting quadratic

pine sail
#

There is NO NEED of square root.

#

And yes, (-3) is not a solution.

#

Because it is not in the domain.

ivory flare
#

This was the answer sheet the teacher provided

pine sail
#

They are wrong.

swift marsh
#

Teacher wasn’t paying attention

ivory flare
pine sail
#

9w^2 - 108 = 9w

ivory flare
#

Gosh if my teacher was actually good i wouldn't be here guys😭 but i cant believe the answer sheet is wrong

pine sail
ivory flare
swift marsh
#

It’s not that big of a deal they just forgot to check at the end

pine sail
#

Yeah happens to the best of us.

#

I guess.

pine sail
ivory flare
restive ridge
#

-3 is a correct solution

ivory flare
pine sail
restive ridge
#

Yes

pine sail
#

...

#

9(-3) = -27

ivory flare
#

To the power of 2?

pine sail
#

RHS has no powers.

restive ridge
#

$\ln{-n} = \ln{-1} + \ln{n} = \ln{n} + (2k + 1)\pi i, k \in \mathbb{Z}$

warm shaleBOT
#

illuminator3

ivory flare
#

Whoa

#

That's like a cool magic trick

swift marsh
#

Lmao this is obviously over the real numbers

pine sail
#

Exactly

#

I don't think beargur knows complex numbers yet.

restive ridge
#

they used them in their attempted solution

ivory flare
ivory flare
pine sail
#

But you are taking those in your solutions, interesting.

ivory flare
#

My teacher is nice she's just all over the place and scattered

pine sail
#

Then I'll have to agree, this isn't limited to real numbers my bad.

ivory flare
#

So my answers and methods are scattered

pine sail
ivory flare
restive ridge
# ivory flare That's like a cool magic trick

yea it's due to the fact that $$\begin{align}e^{i\theta} = \cos{\theta} + i\sin{\theta} \ \implies e^{i(2k+1)\pi} = \cos{(2k+1)\pi} + i\sin{(2k+1)\pi} = -1 + i0 = -1 \ \implies \ln{-1} = i(2k + 1)\pi, k \in \mathbb{Z}\end{align}$$

swift marsh
#

Have you just started learning about logarithms

restive ridge
#

ok texit sux

pine sail
#

If a complex valued logarithm is acceptable then definitely (-3) is a solution.

ivory flare
warm shaleBOT
#

illuminator3
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

pine sail
#

If you are just talking about real numbers, then it's just 4.

restive ridge
#

there

ivory flare
#

I thought i understood them but I apparently don't

swift marsh
pine sail
#

Before =

ivory flare
restive ridge
ivory flare
#

Im in 11th grade taking the American curriculum

swift marsh
ivory flare
#

@pine sail how do you solve that quadratic though?

pine sail
#

...

ivory flare
#

My guy said dot dot dot my bad

swift marsh
#

Usually you just reject the negative domains because once you first see logarithms and for quite a while we generally just consider them over the real numbers

pine sail
#

I think an Eleventh grader is expected to solve quadratics?

#

But I'll tell you.

#

You can factor it out.

#

Or use quadratic formula.

ivory flare
pine sail
#

Sure.

ivory flare
pine sail
#

Yes that thing.

ivory flare
#

Oh i tried factoring it out and i got stumped at w²-12

pine sail
#

There's no w^2 - 12

#

How did you end up at that?

restive ridge
#

here you get taught solving quadratics in 7th/8th grade

pine sail
#

@restive ridge I still doubt there's complex numbers involved.

ivory flare
#

I uh took out the 9

pine sail
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Rather w^2 - w - 12

ivory flare
restive ridge
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assuming a complex valued logarithm

pine sail
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I know it's a solution dude.

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I agreed to it.

ivory flare
restive ridge
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anyhow

pine sail
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I said, I don't think beargur is working with those just yet

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But whatever

swift marsh
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Yeah I don’t think complex-valued logarithms are in a standard American curriculum, I’m not American but I did an SAT once and the only thing in it was just multiplying them, seems like a steep slope to climb

ivory flare
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Is that German