#help-27

1 messages · Page 178 of 1

timid peak
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is there a more calculation type of way to do it? Like the characteristic polynomial method for sequences where theres both an and an-1 term

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@upper schooner

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ahh wait

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for d, we know subsequences nk =2k-1 (odd terms) are increasing

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and mk=2k (even terms) are decreasing

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thats it not sure how to find the limit that both subsequence converge to

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<@&286206848099549185>

timid peak
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@zealous bloom

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do you think you'd able to help?

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nevermind 6.4 for now..

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do you know how to do these?

timid peak
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oh my goodness

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im giving up for today

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ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

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ok

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i'll be back

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gusty merlin
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Hi

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gusty merlin
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Js need help w this

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I’ll rotate

tardy mulch
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The volume of a prism is the surface area of the side multiplied by the length

gusty merlin
tardy mulch
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Yup

gusty merlin
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Which is 64

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68*

tardy mulch
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Yep 68

gusty merlin
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So the volume of the hexagonal prism would be 68m^2

tardy mulch
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M^3

gusty merlin
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Thank you

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Could u also help me with the second one?

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  1. B
tardy mulch
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That one seems alot harder, let me have a think

gusty merlin
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Ik that to calculate the volume of a prism it is v= 1/3 a h

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So would it be 1/3x17x4?

tardy mulch
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It is hexagonal based

gusty merlin
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Yes

tardy mulch
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I'm not sure what the intended method is, but there is a formula here

gusty merlin
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Oh

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So it’ll be square root /2 a^2 h

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Which part is a and which part is h

tardy mulch
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And a is different here I think

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H is 4

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But a is the side length of the hexagon

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This seems like the wrong method

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It's very annoying to calculate a

gusty merlin
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Yea bc we don’t have a n stuff

tardy mulch
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Yeah sorry mate not sure

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You could try calculate a using formula for surface area of hexagon

gusty merlin
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I figured it out thanks so much for the first one tho

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modern spear
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I need exact value for q and p to tell that this is dividable. What do I do next?

modern spear
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I know that I need to tell that q and p must equal to 0 but not sure what to do next

green kelp
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No

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Simple remainder theorem

solar goblet
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oh yeah that i forgot

old nimbus
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i dunno how to solve it guys who can help me?

solar goblet
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modern spear
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In the previous task, the remainder was x(p-14)+12+q and from here I can say that p is 14 and q is -12, but I don't know how here?

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Well the problem here is +1

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@modern spear Has your question been resolved?

modern spear
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<@&286206848099549185>

modern spear
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proud rock
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Two candidates were standing in an election. Of the total number of people in the electoral roll in that election, 10% did not use their votes and 60 votes were declared invalid. The winning candidate secured 47% of the total votes of the voter list and he won the election by 308 votes. How many votes were cast in that election and how many votes did the losing candidate got?

twilit comet
proud rock
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anyone ?

proud rock
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.

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ripe ore
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Hello, could someone please guide me through understanding the intuition of the definition of local maximum?

ripe ore
uncut crow
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everywhere “near” x*,the function is less than or equal to f(x*)

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“near” means the points less than epsilon distance away from x*

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so there is some, perhaps very small, region around x* where nothing exceeds f(x*)

ripe ore
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hmm ive been trying to understand that, maybe i need to visualise it. Lets say for this graph what could a good epsilon value be

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so i can yk visualise it myself and use real values to understand it properly

jaunty mantle
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Say you’re standing on the line

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If you look to your left the floor isn’t going upwards

uncut crow
jaunty mantle
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If you look to your right the floor isn’t going upwards

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So you are “higher than your surroundings”

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And you can kinda shrink “surroundings” to as small as you like, cantered at you but not 0

ripe ore
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what I dont get is why is it not using f(x) < f(x*)

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but its using x < x*

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????

uncut crow
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oh lmao that’s a typo

jaunty mantle
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Oh, yeah

ripe ore
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so is this a typo too

uncut crow
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no

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well that’s weird

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it doesn’t introduce a function in the definition

jaunty mantle
uncut crow
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so it looks fine

jaunty mantle
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This is right too

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There’s just a red herring picture of a function

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😭

ripe ore
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im still confused

uncut crow
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it is probably supposed to be an example where A is the image of f

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but it’s not written well

ripe ore
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can one of yous rewrite the definition in a way i should understand

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so i can make a link with your definition and what the slide's definition tries to imply

uncut crow
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the maximum def there is fine, although it should clarify x* should be in A

ripe ore
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in this case are the x and x* the "heights" of the functions? (the y axis)

uncut crow
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in the local max definition, x <= x* should instead be f(x) <= f(x*) but is ok otherwise

ripe ore
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and why is that different to global max, shouldnt it be f(x) too?

uncut crow
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yea there should be a f(x) <= f(x*) in the definition of global max too

ripe ore
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okay tysm

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i think i understand it, i was just so confused and trying to wrap my head around why it wasnt including f(x)

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i was soooo confused why it only depended on the input values

uncut crow
ripe ore
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so its less of an understanding the logic issue more of a bad definition

uncut crow
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yes lol

ripe ore
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ty for help

uncut crow
ripe ore
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wary oxide
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test

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wary oxide
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i cant find the way

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pls teach me

frank summit
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try synthetic division

covert root
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x^100 + 1 = quotient*divisor + remainder

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The remainder should be at least one degree lower then the divisor in other words in the form ax+b

wary oxide
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wait, i'm trying to understand

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my English to math kinda bad

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sorry, i still don't understand how to get the ax+b form

covert root
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So what is the divisor

wary oxide
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(x-1)²

covert root
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So we have x^100 + 1 = quotient*(x-1)^2 + ax + b

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When we sub x=1 we get:

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1^100 + 1 = a+b

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So at the very least we can eliminate option A

wary oxide
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ooohhh i get it now

covert root
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Try to think about what to do next

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x^100 + 1 = (x^50 - i)(x^50 + i)

wary oxide
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is the i necessary?

covert root
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I am just thinking. I don't know what to do

wary oxide
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i don't know what's next

covert root
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Maybe take the derivative

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Taking the derivative we get

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$100x^{99} = q(x)2(x-1) + q'(x)(x-1)^2 + a$

woven radishBOT
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team132

covert root
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From there when you sub x = 1, you can find a

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From there it is easy to find b. Since we know a+b = 2

devout snowBOT
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@wary oxide Has your question been resolved?

untold bough
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factor theorem

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/ remainder theorem in this case

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(x - 1)² has two roots but they're the same so let's treat it as a linear factor

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as we know x - 1 = 0
x = 1

sub 1 for x¹⁰⁰ + 1
= 2

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remainder theorem states that
given a linear / (can be any degree) divisor, the remainder can be found using f(-b/a) / f(solution to polynomial = 0)

untold bough
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unfortunately he didn't compute the fact that 1^anything = 1

wary oxide
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i think i get the idea

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sorry for the late response

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I'm not very good at understanding math at other languages

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Thanks for helping

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🙂

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bold peak
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can someone help me write the contrapositive of this statement:

In Powerlifting getting a successful lift is equivalent to gaining a point. In a power meet if there does not exist a competitor such that they bench less than 100kg, then all competitors are strong because they have big muscles.

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@bold peak Has your question been resolved?

topaz axle
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"because" can be replaced with "and"
"if there's one competitor who is weak, or there's one competitor who doesn't have big muscles, then there's one competitor who can bench less than 100 kg"

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one is short for "at least one"

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wooden cairn
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hi

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wooden cairn
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in the u and v plane, ie the real line

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why do we exclude 0?

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sleek bough
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Can some one help me with this question

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sleek bough
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I am on the step in which I got the squares under the roots

solar goblet
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show your work

sleek bough
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I let log_2 x = a

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I got sqrt((a+1)^2)+sqrt((a-3)^2)=4

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And I am stuck on the step of inequalities and intervals

restive river
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you need to consider |a+1|+|a-3|=4
intervals would be a<-1, -1<=a<3, a>=3

tough cove
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there is an easier way to solve this equation if you know the graph

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its basically a pot

tough cove
sleek bough
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when a<-1. I solve that a=-1, contradiction?

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when -1<=a<3, I solve that 4=4 which is wierd

sleek bough
lime field
sleek bough
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?

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the log_2 (x) is like the inverse of the exponential function right?

restive river
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yes

restive river
sleek bough
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x increase when the a increase

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wait:
here is the list of interval
a<-1, invalid
a=-1,valid,x is 0.5
-1<a<3, the expression is always 4 regardless of x
a=3, x is 8
a>3,a=3, invalid again

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so x_max is 8, and x_min is 0.5, is my thought correct?

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Hmm, is the answer an interval of X?

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Oh the solution is indeed 0.5~8

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Thanks guys

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bright juniper
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Need to find every value of a so the equation has an answer

pastel pasture
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what do you know about exponentials

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in particular, about their range?

bright juniper
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Mhh not sure

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bright juniper
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restive river
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restive river
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i am not sure on what the minimum spanning tree is or how much the branc

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Weighs

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I asked this wuestion earlier waited about 2 hours and no one helped guyz 🙏

devout snowBOT
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@restive river Has your question been resolved?

restive river
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<@&286206848099549185>

devout snowBOT
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@restive river Has your question been resolved?

tame palm
restive river
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I told u im not sure

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If i can

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Its alot more dofficult then anything ive ever done

tame palm
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Does this help?

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And do you understand how Prim's Algorithm works?

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You are told to start at vertex A so you add vertex A to the spanning tree. Prim's Algorithm states that you assess the weight of all the edges currently connected to the spanning tree and choose the edge with the smallest weight that does not create a cycle, meaning an edge that does not connect back to the spanning tree.

tame palm
tame palm
devout snowBOT
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@restive river Has your question been resolved?

tame palm
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Do you understand what the algorithm is asking you to do so far?

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@restive river

restive river
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hold on i will look

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now

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hmm

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yes i know what its asking me to do

restive river
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@tame palm come back my friend!!!!!!

tame palm
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Ok

restive river
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hi

tame palm
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Prim's Algorithm says to add the vertex connected to that edge to the spanning tree. You then consider all of the edges connected to the updated spanning tree.

restive river
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why is b to g one of them

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i thought making a cycle wasnt allowed

tame palm
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Because it is an edge connected to the spanning tree.

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The purple are candidate edges.

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Green is the current spanning tree.

restive river
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right

tame palm
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BG is an edge specified in the adjacency matrix given by the problem.

restive river
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so

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the minimum weight is then 61+18?

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i thought the tree would have looked like this 😭

tame palm
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No, you need to connect all of the vertices to find the minimum spanning tree. Prim's Algorithm gives you a methodical method to find that minimum spanning tree that has edges with the smallest weight.

restive river
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so you are saying it would be like this?

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or do i need to connect the top right part too?

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sorry i am very new to this topic

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and my worksheet i dont know if im stupid or its just not very clear

tame palm
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No.

restive river
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oh

tame palm
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You determined that AB is the lighter edge so you add B to the spanning tree connected to A.

restive river
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yes

tame palm
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From there, you examine all of the edges connected to the updated spanning tree (green).

restive river
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oh

tame palm
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Which edge has the lightest weight amongst the candidate edges (purple)?

restive river
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18

tame palm
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Ok, and that edge is connect to vertex G so you add that vertex to the spanning tree.

restive river
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so

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is this the total tree

tame palm
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Now consider all of the candidate edges connected to the updated spanning tree.

restive river
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8!!!

tame palm
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Good.

restive river
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oh

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do i take 29?

tame palm
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Check all of the edges. There is one that is less than 29.

restive river
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oh

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28

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g toc

tame palm
restive river
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now its 29

tame palm
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Correct.

restive river
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33?

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i rthought i couldnt make loopsss

tame palm
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You can't.

restive river
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oh okay

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then 51

tame palm
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EF is not a valid connection to make in the minimu spanning tree.

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Correct.

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There. Now all of the vertices are connected and you have a minimu spanning tree.

restive river
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so this is the tree!!!!!

tame palm
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Now all you need to do is add the weights of the green edges to calculate the weight of the minimum spanning tree.

restive river
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so the mimimum weigh is 195

tame palm
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Yes.

restive river
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yesssss

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thank you so much bro

tame palm
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yw

restive river
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genuinely u helped make it so much more clear

tame palm
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Do you understand how the algorithm works now?

restive river
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yesss

restive river
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if that is okay with you

tame palm
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Ask away.

restive river
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it is

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my worksheet does not mention any of those

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so i dont really know what they mean

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and whatever this is

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i asked my mom and she said google but google isnt

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understanding me

tame palm
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Do you know what a Eularian Graph is?

restive river
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well

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only from what i have googled

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lol

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its a graph that has a connection to every verticie

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i think?

tame palm
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No. A Eularian Graph consists of vertices that are an even degree. The degree of a vertex is the number of edges connected to it, that includes looping edges.

restive river
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doesnt it always have to be even

tame palm
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In the above graph, vertex B has two edges connected to it so it is an even degree.

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Yes, a Eularian Graph can only have vertices of even degrees.

restive river
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well

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d doesnt have even

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or a

tame palm
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A Semi-Eularian Graph can only have two odd vertices.

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So is the graph above a Eularian Graph?

restive river
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no

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only a and d

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so it is semi

tame palm
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👍

restive river
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2 odd ones

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it would be neither?

tame palm
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Correct.

restive river
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okay i see

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ty very much

tame palm
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yw

restive river
tame palm
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I'm not using one.

restive river
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oh

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you were just drawing lines haha

tame palm
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I made the graph using Geogebra.

restive river
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will i get it right

tame palm
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That's a link to the Geogebra file I made the Minimum Spanning Tree in.

restive river
#

isee

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ty

tame palm
restive river
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is there an easier way

tame palm
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Probably not. If you do find one, you should share it with the world. 😉

restive river
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okay

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i am working on it

restive river
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why is it 0

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oh

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its not

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lol

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its 2?

tame palm
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The edge connecting D to H? It has weight of 2.

restive river
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yah okay

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if i follow these instructions for this question

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oops

tame palm
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You forgot EH.

restive river
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sorry im making the things

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pop up on my page

restive river
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what does it mean by all possible pairings

tame palm
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Any edges that connect two odd vertices.

restive river
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theres none

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directly

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oh pairings

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so two

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or 4

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umm

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cause there is no 2

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this better not be a 2 paths thing

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where has my king gone

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steady onyx
#

how do I determine the coefficent of a³b²c² in the development of (a+b+c)^7

fervent sundial
steady onyx
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i believe so

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it is just tricky doing it with the three terms instead of two

fervent sundial
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I mean you can read off the coefficient if you know the multinomial theorem lol

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the coefficient of a^3 b^3 c^2 is just

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,, {n \choose {3,2,2}} = {7 \choose {3,2,2}} = \frac{7!}{3! \cdot 2! \cdot 2!}

steady onyx
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so

woven radishBOT
steady onyx
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yeah

fervent sundial
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yeah so it's just 210

woven radishBOT
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Result:

210
steady onyx
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would this correspond with the multinomial theorem?

fervent sundial
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bi = 2 things

steady onyx
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oh

fervent sundial
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multi = more than 2 things

#

,, (x_1 + x_2 + x_3)^n = \sum_{k_1 +k_2+ k_3; k_1,k_2,k_3 \geq 0} {n \choose k_1, k_2,k_3} \prod_{l=1}^mx_l^{k_l}

woven radishBOT
steady onyx
#

then i havent done that yet

#

could you find the answer using binomial theorem?

fervent sundial
#

I mean binomial theorem is for binomials (sum of two terms)

#

a + b + c is the sum of three terms

steady onyx
#

true

#

however i have been asked this question in the context of a binomial theorem chapter

fervent sundial
#

well i guess you can treat a+b as one term and c as another

steady onyx
#

hmm

#

i will have a go at that

#

thank you

#

.close

devout snowBOT
#
Channel closed

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Use .reopen if this was a mistake.

steady onyx
#

.reopen

devout snowBOT
#

steady onyx
#

I have had an issue with that

#

where i get (a^(7-i))*(b^i+c^i) = a³b²c²

#

.close

devout snowBOT
#
Channel closed

Closed by @steady onyx

Use .reopen if this was a mistake.

fervent sundial
#

U didn't ping me so i didn't see lol

steady onyx
#

yeah

fervent sundial
#

you should probably reopen your channel first

steady onyx
#

.reopen

devout snowBOT
#

fervent sundial
#

,, (a+b+c)^7 = \sum_{k=0}^7 {7 \choose k} a^{7-k} (b + c)^k

woven radishBOT
fervent sundial
#

we had the splitting into two terms thing i mentioned prior right?

steady onyx
#

yeah

steady onyx
fervent sundial
#

we want the coefficient of a to be 4

#

so 7 - k = 4

#

k = 3

steady onyx
#

yeah

fervent sundial
#

actually wait

#

we want the coefficient of a to be 3 not 4

#

so k = 4

steady onyx
#

mhm

fervent sundial
#

so we have ${7 \choose 4} \cdot a^3(b + c)^4$

#

finally we want b^2 c^2

#

,, (b+c)^4 = b^4 + 4b^3c + {\color{red}6}b^2 c^2 + \ldots

woven radishBOT
fervent sundial
#

so the coefficient of b^2 c^2 is 6

woven radishBOT
steady onyx
#

you're quick

#

gimme a sec

fervent sundial
#

LOL

#

okay okay

steady onyx
#

okay i get it

fervent sundial
#

yeah so it's just ${7 \choose 4} a^3 \cdot (b^4 + 4b^3 + {\color{red} 6b^2 c^2} + \ldots)$

woven radishBOT
fervent sundial
#

the coefficient is then just 7C4 * 6

steady onyx
#

which alligns with the multinomial

fervent sundial
#

since technically you just have ${7 \choose 4} a^3 6b^2 c^2 = {7 \choose 4} \cdot 6 a^3 b^2 c^2$

woven radishBOT
fervent sundial
#

yeah it should

#

,w (7 choose 4) * 6

woven radishBOT
fervent sundial
#

anyway yeah multinomial was probably quicker lol

steady onyx
#

i guess

steady onyx
fervent sundial
#

it's 7 choose 4 btw

steady onyx
#

o yeah

steady onyx
#

indeed

fervent sundial
#

we want the exponent of a to be 3 but now it's at 7-k

#

7-k = 3 gives k = 4 for which we'd have a^3

#

so now we sub the value k = 4 into this part:

#

so we get:

7C4 * a^3 * (b+c)^4

#

our goal is to get b^2 c^2 from the (b+c)^4 term

steady onyx
#

from what it was in the original form

fervent sundial
#

(b+c)^4 = b^4 + 4b^3 c + 6b^2 c^2 + .... so the coefficient with the b^2 c^2 is 6

fervent sundial
#

the coefficient of a^3 b^2 c^2 is then just 7C4 * 6

#

are you still confused or do you get it now? Lol

steady onyx
#

or am i just not thinking straight

fervent sundial
#

,, {7 \choose 4} a^3 (b^4 + 4b^3 c + 6b^2 c^2 + ...)

woven radishBOT
fervent sundial
#

but do you notice that you multiply 7C4 * a^3 to every term?

steady onyx
#

yes

fervent sundial
#

,, {7 \choose 4} a^3 (b^4 + 4b^3 c + 6b^2 c^2 + ...) = {7 \choose 4}a^3 b^4 + {7 \choose 4}a^3 \cdot 4 b^3 c + {\color{red}{7 \choose 4}a^3 \cdot 6 b^2 c^2} + \ldots

#

we're only concerned about the red term

steady onyx
#

okay

woven radishBOT
fervent sundial
#

i'm just expanding the left hand side btw if that wasn't apparent

#

since u said i "elected"

#

i elected cuz the red thing is the only thing that matters

#

but i think it should be fairly obvious now that i expanded things out

steady onyx
#

yes i think so too

#

i might be a bit tired actually

#

because you have given plenty of explanation

#

i will review it tomorrow and it should probably click then

fervent sundial
#

I mean you can come back to it later

#

yeah

steady onyx
#

okay

#

well i appreciate your help very much

#

and you patience even more

fervent sundial
#

sure, no worries lol

#

hopefully you get it the second time around

steady onyx
#

okay, thanks a bunch

#

.close

devout snowBOT
#
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devout snowBOT
#
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prime narwhal
devout snowBOT
#

The original post of this help channel has been deleted, and it will abruptly close and possibly lock. (This is irreversible.) Please claim a new channel, and don't delete the first message of any future channel you claim.

prime narwhal
#

i sent it again

dense jay
#

the channel is going to lock

prime narwhal
#

bruh

#

ill open a new one

#

.close

eager nova
#

Just open a new one

devout snowBOT
#
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sturdy sigil
devout snowBOT
sturdy sigil
#

i need help with calculus

#

dinner with kanye

#

lmfao

devout snowBOT
#

@sturdy sigil Has your question been resolved?

devout snowBOT
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ember notch
devout snowBOT
ember notch
#

can someone explain? teacher barely went over it

mortal vale
ember notch
#

OH I FORGOT THE DEGREE SYMBOL

#

wow

devout snowBOT
#

@ember notch Has your question been resolved?

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restive river
#

Hey, is finding the rate of change of a given function $f$ at point $P$ in the direction of unit vector $\vec{u}$ exactly the same as computing $D_{\vec{u}} f(P) = \nabla f(P) \cdot \vec{u}$?

woven radishBOT
timber pebble
#

i believe you have the form though

restive river
#

I was just wondering if the directional derivative gave the rate of change of f at a certain point

timber pebble
#

for a 2 variable function it doesnt make sense to say "the rate of change" as in a number

#

you have to say in some direction

#

or generalize to the gradient

timber pebble
restive river
#

Have a good one

#

.close

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#
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worthy oxide
devout snowBOT
worthy oxide
#

hi i need help understanding how to tell if a function is convergent or divergent using the comparision theorem

#

i have watched a few videos about it but i cannot seem to grasp it

#

i know that this function is convergent but it would be helpful to see the work and thought process behind it

#

thank you any help is appreciated

eternal tree
#

well $\frac{1}{x+e^{2x}} < \frac{1}{e^{2x}}$ for $x > 1$

woven radishBOT
#

Waffloid

worthy oxide
#

yea that makes sense

eternal tree
#

but then, we can explicitly evaluate $\int_1^N e^{-2x}$

woven radishBOT
#

Waffloid

worthy oxide
#

what is N?

eternal tree
#

just some dummy variable that we'll take to infinity after we evaluate the integral

#

technically u could just directly go and calculate $\int_1^\infty e^{-2x}$, depends how formal u wanna be

woven radishBOT
#

Waffloid

worthy oxide
#

oh ok why do we want to calculate that integral?

eternal tree
#

so if the bigger integral converges, then the smaller one does too

#

ie we apply the comparison test

worthy oxide
#

bigger out of 1/e^2x and 1/x ?

#

why are we only taking one part out of the integral if that makes sense?

eternal tree
#

okay ill explain my thinking

#

we want to show that $\int_1^\infty \frac{1}{x+e^{2x}}$ converges

woven radishBOT
#

Waffloid

eternal tree
#

the way id want to do this would be to just calculate it direclty and be like "this is equal to some number C so it converges!"

#

but instead we arent so lucky and we cant calculate it direclty

#

so instead, we want to find an integral, that should be strictly larger, that we can calculate the value of directly

eternal tree
#

thats why i compare it against $\int_{1}^\infty \frac{1}{e^{2x}}$

woven radishBOT
#

Waffloid

eternal tree
#

dropping the x term gives me a smaller denominator, so overall a larger function

#

and thus overall a larger integral

worthy oxide
#

would'nt 1/x be bigger?

eternal tree
#

well yea

#

but thats way too much bigger

#

roughly speaking i chose this one coz its a better estimate for 1/(x+e^2x)

#

the integral $\int_1^\infty 1/x$ doesn't even converge

woven radishBOT
#

Waffloid

eternal tree
#

so while indeed you could try to compare against this, it doesnt tell u anything

worthy oxide
#

ok i think i got it btw the problem is asking if it is convergent or divergent not necassarily trying to prove convergence

eternal tree
#

sure

worthy oxide
#

alright so we evaluate1/e^2x

#

as an integral?

eternal tree
#

yea

#

we're saying that $\int_1^\infty \frac{1}{x+e^{2x}} < \int_1^\infty \frac{1}{e^{2x}}$

woven radishBOT
#

Waffloid

eternal tree
#

so ye

#

you can just plug in the integral of e^-2x and put the bounds in

#

should give you $e^{-2}/2$ overall

woven radishBOT
#

Waffloid

worthy oxide
#

-2 what about the x

#

?

#

oh ok

#

yea i got

eternal tree
#

we calculate the indefinite integral of $e^{-2x}$ as $-\frac{1}{2}e^{-2x}$

worthy oxide
#

it

eternal tree
#

then we sub it in

#

yeah

#

sure

worthy oxide
#

yea that makes sense

#

ok well

woven radishBOT
#

Waffloid

eternal tree
#

okay cool

worthy oxide
#

so if it was convergent it would be infinity right?

#

or sorry

worthy oxide
#

divergent

eternal tree
#

yes, but be careful

#

you can't conclude from an upper bound estimate that your integral is divergent

worthy oxide
#

?

eternal tree
#

eg if you said $\int_1^\infty\frac{1}{x+e^{2x}} \leq \int_1^\infty \frac{1}{x} = \infty$

#

you cant conclude from this that the integral is divergent

worthy oxide
#

because that would be false rightt?

worthy oxide
#

or because you jsut cant use the upeer bound

eternal tree
#

its just that this doesnt tell us anything

woven radishBOT
#

Waffloid

eternal tree
#

the comparison test doesnt apply here

worthy oxide
#

how would that be true tho?

eternal tree
#

well whats wrong?

worthy oxide
#

1 over infinity would be 0 right

#

?

#

wiat

#

never

#

mind

#

its an integral

eternal tree
#

yep

#

the integral is ln

worthy oxide
#

ok so you would use lower bound for divergence?

eternal tree
#

exactly

worthy oxide
#

if you did not know before hand if it was divergent or convergent how would you start then?

#

or would you just use both

eternal tree
#

you develop an intuition for whether an integral is divergent or convergent

#

theres some rules of thumb

#

eg, if we had $\int_1^\infty \frac{1}{3x^2 + x}$

woven radishBOT
#

Waffloid

eternal tree
#

i know that this is "basically" the integral of $\1/x^2$, which i know converges in this interval

woven radishBOT
#

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

eternal tree
#

to make this precise, id give an upper bound of 1/3x^2 and note that this converges

#

in general, the behaviour of convergence/divergence is roughly determined by the most powerful term, so u can ignore the smaller things and just look at how that behaves

#

this is prolly quite vague without context tho, so feel free to send a few more examples and i can be more concrete

worthy oxide
#

what would be the lower bound in this problem

#

ok i will send one more

#

thank you for your help

#

btw

#

i really appreciate it

eternal tree
#

no worries :)

worthy oxide
eternal tree
#

interesting

#

hmm

#

thats a lot less obvious

#

my first thoughts are

#

as x is small, sin(x) is roughly x

#

and i think(? will have to double check) that the integral of 1/x^2 diverges if its in an interval 0 to something positive

#

which would mean this diverges

#

yeah i think this works

worthy oxide
#

ok

#

so

#

let me think for a minute

#

where did you get x^2

#

?

eternal tree
#

intuitively, sin(x) and x are almost the same for small x

#

eg look at the graph;

#

so i thought about whether it converges if i replace sin(x) with x, since as they are so similar they should have the same answer

worthy oxide
#

ok but doesn't sinx go up and down while x would just go up forever?

eternal tree
#

true, but look at the bounds we are integrating over

#

0 to pi/2

worthy oxide
#

ohohohohoho

#

oyeoyoayroeuo

#

yea

#

yea

#

okokok yea

#

ur right

eternal tree
worthy oxide
#

ok yea that makes sense

#

but why would it be divergent would'nt 2/(pi/2)^2 be a number ?

eternal tree
#

wdym?

worthy oxide
#

like when you intgerate 2/x^2

#

wait

eternal tree
#

yeah but try evaluate that at 0

worthy oxide
#

yea at 0 it would be 0

eternal tree
#

uhh

#

you'd be doing 1/x and x = 0

worthy oxide
#

but then it would be - the pi 2 right

#

so does the first part being non existent completly negate the other part

eternal tree
#

i dont follow

worthy oxide
#

like it is for sure divergent if it is ever divided by 0?

#

like any time 1/0 or 3/0

#

subrtact by the other plug in during the function

#

it would always be divergent?

eternal tree
#

i think so

worthy oxide
#

ok

#

yea that makes

#

sense

eternal tree
#

like, the way id justify it is

#

say the integral of f(x) is F(x), and i want to calculate, say, the integral of f between 1 and 0, which is F(1) - F(0)

#

if calculating F(0) is given by 1/0

#

then close to 0, we have stuff blowing up to infinity

#

eg

#

F(0.01) would be like 1/0.01 = 100

#

F(0.0001) = 1/0.00001 = 100000

#

so when we see a 1/0, its pointing at the fact we have this blowup happening

worthy oxide
#

ok i think i get it

#

yea

#

ok

#

alright i have one more question if that is alright

eternal tree
#

sure

worthy oxide
#

wait

#

actually i think this exsplanation answered

#

the question

eternal tree
#

great

worthy oxide
#

but let me make sure

eternal tree
#

go for it

worthy oxide
eternal tree
#

fun

worthy oxide
#

so this would be divergent because it would be ln(1/0 +tan()) right?

eternal tree
#

hmmm

#

maybe, ill walk u through what im thinking

#

sorry thats nonsense LOL

#

hmm

#

looks pretty divergent

eternal tree
#

u can turn it into one though along the lines of what i was saying though yes

#

personally id consider smth like

#

$\int_0^x 5\sec(x)$

woven radishBOT
#

Waffloid

eternal tree
#

and then note that taking x to pi sends the value to infinity

worthy oxide
#

ln(sec+tan)?

eternal tree
#

which is basically the same as what u said

eternal tree
#

tan(pi) = 0 but sec(x) -> infinity as x -> pi

#

informally sec(pi) = infinity

#

so ln(sec(pi)+tan(pi)) =ln(infinity)= infinity so it diverges

#

to make this "formal" though we talk about limits

#

the level of detail ur argument needs depends on ur teacher tho ig

#

but u were right all along anyway

#

soz for dragging it out a bit, seems you understood my point better than i did...

worthy oxide
#

Ok

#

My computer just died btw

#

On my phone now

#

But yea

#

I think i got it for the most part

#

Have a great day

eternal tree
#

wonderful

worthy oxide
#

.close

eternal tree
#

thanks you too

devout snowBOT
#
Channel closed

Closed by @worthy oxide

Use .reopen if this was a mistake.

devout snowBOT
#
Available help channel!

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Ask your math question in a clear, concise manner.
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After 15 minutes, feel free to ping <@&286206848099549185>.
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polar cargo
#

Pls help me.

devout snowBOT
polar cargo
#

Algebra 1

#

I’m not sure what 8 is asking on part b and c. The 9 is just confusing

steady forge
polar cargo
steady forge
#

,rotate

woven radishBOT
steady forge
#

could you explain which part is confusing

polar cargo
#

Where it says to find the distance I’m not sure how to do it. Am I supposed to add the or that part C. Or add them?

steady forge
#

well its just asking the distance between the points

polar cargo
#

Do I add it

steady forge
#

well how would you get the distance here

polar cargo
#

Adding 5

steady forge
#

could you explain what you mean

polar cargo
#

No you add 10 oops. Cause you add 5 to get to zero then add 5 to get to five

thin pagoda
#

Man just use chat gpt

steady forge
#

yes

#

so 5-(-5)

steady forge
#

not really my problem

thin pagoda
#

Help me

#
  1. b
steady forge
#

this is not your channel

#

open your own

thin pagoda
#

Why

steady forge
#

open your own.

thin pagoda
#

Why though

#

Will you help

steady forge
#

because it's rude and it's not that hard

#

open your own channel

steady forge
polar cargo
#

I’ll try then let you know if I got it

#

Got 75. I put zeros for the x’s

steady forge
#

well, it's asking for the width of both arches, not how high the arch is

polar cargo
#

Not 15 a 10 and 19

#

10

#

20

#

Answer=20

steady forge
#

yes

polar cargo
#

For 9. Am I just plugging in the 3 for t?

steady forge
#

yep

#

also for your factored form

#

factored form of a quadratic is just y=a(x-x1)(x-x2) where x1 and x2 are the zeroes of the function

#

so you don't have to solve

#

recheck your factoring though

polar cargo
#

Opps I wrote 8

devout snowBOT
#

@polar cargo Has your question been resolved?

#
Channel closed

Closed by @polar cargo

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devout snowBOT
#
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After 15 minutes, feel free to ping <@&286206848099549185>.
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manic osprey
devout snowBOT
manic osprey
#

Can someone explain how they got 5 to the power of 2 like is there a rule or something

weak cove
#

yes, ln(a^b)=bln(a)

manic osprey
weak cove
manic osprey
#

Oh it’s in my notes lol

#

Wait

#

I don’t get this

weak cove
#

What do you not understand?

manic osprey
#

How does it turn into In10

weak cove
#

they swapped the direction of the equality

manic osprey
weak cove
#

It's just a question so I can help

#

take the first line

#

swap it around

#

10=e^(5-3x)

#

then take the ln of both sides

#

ln(10)=ln(e^(5-3x))

manic osprey
weak cove
#

and another log property for you

#

ln(e^(a))=a

#

so that is why

manic osprey
#

How do u know to take In of both sides

weak cove
#

because you want to solve for x

#

and it's up in the power of e

#

so you want to get it down

#

you want to undo the exponentiation

#

ln is the inverse of exponentiation

#

just like multiplication inverts division

#

if you have 5x=10

#

you divide

#

because you want to undo the multiplication by 5

#

to solve for x

#

so when you have y=e^x

#

you take the natural log

#

to undo the e^...

#

ln(y)=x

#

Does that help you understand?

#

I still think you should go watch some videos

manic osprey
#

Ok so

#

e^y like e^5-3x and it equals x like 10 then Inx = y so In10 = 5-3x

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Then isolate x

manic osprey
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any suggestions

weak cove
# manic osprey any suggestions

This algebra 2 / precalculus math video tutorial explains the rules and properties of logarithms. It shows you how to condense and expand a logarithmic expression in addition to graphing and solving logarithmic equations.

Logarithms - The Easy Way!
https://www.youtube.com/watch?v=kqVpPSzkTYA

Log to Exponential ...

▶ Play video
manic osprey
devout snowBOT
#

@manic osprey Has your question been resolved?

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rain bluff
#

The bee population in a certain area is declining at an uninhibited rate of 36.5% per year. How long will it take for that population to be one-fourth of the initial population?

thin inlet
topaz axle
rain bluff
#

mhm

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essentially yes

topaz axle
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they are just saying that 0.635^x = 1/4

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so x = log_0.635(1/4)

rain bluff
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wait wait wait

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hold on i need small steps

topaz axle
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i didn;t say any steps

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i think

rain bluff
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you didnt im just saying i need a slow roll lol

topaz axle
#

after one year the population becomes 0.635 of whatever it was

rain bluff
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like baby steps

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why is that?

topaz axle
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because it loses 0.365

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so the first step is you read 36.5% as 0.365

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then 1 − 0.365 = 0.635

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that's how much is left after one year

rain bluff
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oh

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hm

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thats not one of the options

topaz axle
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why would it be one of the options

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i'm surprised that i'm not surprised

rain bluff
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sorry no not that i tried to fully solve it

topaz axle
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ah my bad

rain bluff
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that being your calculation of how much was left after 1 year

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no no thats on me and my talking to myself

topaz axle
#

you probably need to know this formula to solve it this way

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you use x = e

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so the calculator has a button for this

rain bluff
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mmmm symbolab time

topaz axle
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b = 0.635
a = 1/4

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what are the options?

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maybe i also didn;t get any of them

rain bluff
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probably not, i was doing it a weird way lol

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11.3 and 3.8

topaz axle
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what, 2 options?

rain bluff
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yep

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weird right

topaz axle
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well it's not any of them, so i need to start from scratch

thin pagoda
#

Use chat got

rain bluff
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lmao

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worst advice possible

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chatgpt is somehow dumber than me

thin pagoda
rain bluff
topaz axle
#

ok 3.8 is waht they want

rain bluff
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how did we get there?

topaz axle
#

i can't explain it though

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it's not 36.5% per year, it's a fake number

rain bluff
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??

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fake number

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<@&286206848099549185> second opinions?

topaz axle
rain bluff
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this is a weird ass problem considering it has just 2 options

topaz axle
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0.365 is the rate constant

rain bluff
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ok

topaz axle
#

,calc exp(-0.365)

woven radishBOT
#

Result:

0.69419665087798
topaz axle
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so this is the actual "what's left", instead of 0.635

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then it works out to 3.8

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so it works on an arbitrary rule, and they phrased it in a way like they meant a sensible rule

rain bluff
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oh

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this is weird

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thank you for sticking with it tho!

rain bluff
topaz axle
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i didn't, i don't know that much calculus

rain bluff
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interesting..

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this isnt calc however

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this is alg2

topaz axle
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then they give the formula

rain bluff
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there must be a more reasonable way to get this one

topaz axle
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at some point in some way

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nope

rain bluff
#

strange stuff

#

thanks frownyfrog!

#

.close

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fallen condor
#

How do you use QR factorization of a matrix to find its orthonormal basis?

fallen condor
#

I was under the impression that you need to know the orthnormal basis to find its QR factorizatoin

wicked turtle
#

isn't this essentially gram-schmidt?

devout snowBOT
#

@fallen condor Has your question been resolved?

dawn cairn
devout snowBOT
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restive river
#

Why is the equation of wave not y = Asin(omega(t) - kx)

wicked turtle
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it's probably looking at one fixed value of x

restive river
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They didn’t specify

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So I’m confused

wicked turtle
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hard to say without any context

restive river
#

He just wanted to explain beats. So he considered these two waves to explain their interference

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That was the first step

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Wait this is a screenshot of the pdf he provided