#help-39

1 messages · Page 326 of 1

brisk steeple
#

which part

nocturne night
#

the x is already in the denominator, so you don't have to multiply it

brisk steeple
#

Multiply the numerator by what you multiply the denominator by to ensure that there is no change in the value of the fraction.
Then use the fact that a/x - b/x = (a-b)/x

sinful snow
#

I don't understand

#

I'm multiplying 6y by 2x

brisk steeple
sinful snow
#

i

#

The very start of the question

brisk steeple
#

my bad

brisk steeple
lusty jacinth
#

We multiply 6y by just 2 because we are only trying to make the bottoms match, and the bottom already has an x, so to make the bottom match, we only need a 2. Because we are multiplying the bottom by 2, we do that to the top.

sinful snow
#

So would this apply for every question?

#

Say if it was 5x multiplied by 2y it would just be 2(5x)

lusty jacinth
sinful snow
#

I'm just saying if it was another equation would I ignore the y like I ignored the x

lusty jacinth
#

If you had something like $$\dfrac{5x}{y}+\dfrac{3}{2y}$$
then yes, you would multiply by only 2 on the top. However if you had
$$\dfrac{5x}{5}+\dfrac{3}{2y}$$
You would multiply by the full 2y because there is no y on the bottom of the left fraction.

Does this make sense?

jolly parrotBOT
#

Morgan

sinful snow
#

Ohhhh!!!

#

Yes I get it now

#

Thank you so much I was gonna quit studying cause of this lol

lusty jacinth
#

Glad I was able to help! Good luck studying!

pearl pondBOT
#

@sinful snow Has your question been resolved?

pearl pondBOT
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empty oriole
#

I am struggling to see how he got that formula for q
(3)

empty oriole
#

Oh, I could not find one

#

thanks

empty oriole
#

.close

pearl pondBOT
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sharp vigil
#

all of the answers should be available by scrolling down

pearl pondBOT
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lament storm
#

This should be half life formula, im just not sure how to structure it or break it down?

bitter herald
lament storm
#

Its like A0(1/2)^t/h

bitter herald
#

Yea

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So lets plug in what we know

#

'...has lost 25% of its carbon14'

#

This statement relates to the amount at time t

#

Meaning,
[
A(t) = A_0\8{\412}^{\5th}
]

jolly parrotBOT
bitter herald
lament storm
#

OH

lament storm
bitter herald
#

So like

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We know it starts with A_0 right

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But then, that A_0 loses 25% of its value

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What remains after it loses that much?

lament storm
#

75%?

bitter herald
#

75% of A_0

lament storm
bitter herald
#

no

#

Im saying A(t) is gonna be 75% of A_0

lament storm
#

OH

bitter herald
lament storm
#

ohh ok

bitter herald
#

Yeah

#

Can you write your equation now with those values

#

Ok I gotta go now. Hopefully another helper picks up the slack

hollow barn
#

For this, the simplest way to think about it (since there's no concrete values) is to take A(t) = 0.75 and A_0 = 1

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Since this would mean we start with 100% and are now at 75%

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After some time t

pearl pondBOT
#

@lament storm Has your question been resolved?

lament storm
hollow barn
#

Well you aren't given any specific starting values, so we can assume the starting amount is 1 unit

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Since it correlates to 100% starting

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And then to have 75% left means we have 0.75

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You could also start with 100 and then A(t) = 75

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Just needs to be consistent

lament storm
#

so A(0.75) = A_1 (1/2) ^0.75/5750

#

?

#

is that correct

hollow barn
#

No no A(t) = 0.75

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We don't know what t is yet it's what we want to find

lament storm
#

OHHH

hollow barn
#

Your setup should be $0.75 = (1)\bigg(\frac{1}{2}\bigg)^{\frac{t}{5750}}$

jolly parrotBOT
#

TestTickler

hollow barn
#

Then you should be able to solve for t

pearl pondBOT
#
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sharp galleon
#

Yo guys

pearl pondBOT
sharp galleon
#

Whats the difference between invariant lines and invariant points in matricies

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With invariant lines i js sub in mx right for y

pearl pondBOT
#

@sharp galleon Has your question been resolved?

pearl pondBOT
#

@sharp galleon Has your question been resolved?

sharp galleon
#

,close

#

.close

pearl pondBOT
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north talon
#

Determine all finite, nonempty sets of positive integers $S$ such that for any elements $a,b$ of $S$, there exists some $c \in S$ such that $a | b + 2c$

jolly parrotBOT
#

Copter

north talon
#

clearly if S = {a} works and if |S| = 2 then the only set that works is S = {n,3n}. I need help on the case where S >=3?

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i dunno if thats possible

pearl pondBOT
#

@north talon Has your question been resolved?

north talon
#

<@&286206848099549185>

pearl pondBOT
#

@north talon Has your question been resolved?

sharp smelt
jolly parrotBOT
#

what a wonderful world(wai)

north talon
#

yea

sharp smelt
#

Unless I'm tripping , this implies $a\mid b$ and $a\mid 2c$ no?

jolly parrotBOT
#

what a wonderful world(wai)

sharp smelt
#

so $a=2$ , but we discard this as. then the set is infinite

jolly parrotBOT
#

what a wonderful world(wai)

sharp smelt
#

uh @north talon you still here?

north talon
sharp smelt
#

oops

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right

north talon
#

2 | 1 + 3, but doesnt divide either

north talon
north talon
#

can anyone help?

cursive wraith
pearl pondBOT
#

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pearl pondBOT
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quick venture
pearl pondBOT
quick venture
#

i dont understand where they got n from

fleet ridge
#

Its due to the periodicity of sin and cos

quick venture
fleet ridge
quick venture
fleet ridge
quick venture
fleet ridge
#

So how would you collectively represent all the points?

#

U there @quick venture

pearl pondBOT
#

@quick venture Has your question been resolved?

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thorny radish
thorny radish
#

i don't know why this works but it does

#

well first i should clarify that for bookkeeping since all elements have the same ν₂ we can assume they are all odd

#

.close

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fading nexus
#

For e how will I find the greatest possible width and length?

fleet ridge
#

Assuming you know the value of x, you can just subtract 2x from the original rectangles dimensions

fading nexus
#

Oh I was over thinking it ty

pearl pondBOT
#

@fading nexus Has your question been resolved?

fading nexus
#

For the life of me I can not figure out the window for the volume equation to graph even when I put the one my teacher put it does not work. I tried multiple version of the equations just changing the () to see if that is where I went wrong but it’s the same no matter what u do

fleet ridge
fading nexus
#

So I’m trying to put this volume equation in my calculator to find the maximum so it should be like a hill shape

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but it’s just a straight line

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No matter what window I ajust to

fleet ridge
#

1 minute I'll try desmos

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This is probably why

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@fading nexus the maximum is so abysmal high. Thats why it looks like a straight line in your calculator

pearl pondBOT
#

@fading nexus Has your question been resolved?

pearl pondBOT
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barren arrow
#

can someone help me understand modulo arithmetic for competitive programming?

barren arrow
#

i dont understand the inverse thing

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modulo inverse

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i dont know if this is the correct channel to ask this question or now

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not*

plush bramble
#

can you just show an example or problem of modulo inverse

barren arrow
flint basalt
#

if you have a specific problem that you were working through then send that

flint basalt
#

send whatever you have regarding that problem

barren arrow
#

i am working with this problem

flint basalt
#

and please send a screenshot instead of a link or a pdf

barren arrow
#

so the formula i derived for this question is n * (n + 1) * (4 * n - 1) / 6

plush bramble
barren arrow
#

but i dont understand the modulo part in this question

plush bramble
#

example

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so in your problem instead of the 12 in the example, you have a much bigger number

plush bramble
#

uh no

valid nova
plush bramble
#

10^9 + 7 is not 1e7

valid nova
barren arrow
#

1e9 + 7

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sorry

flint basalt
pearl pondBOT
plush bramble
#

so do you uderstand this then

barren arrow
#

is that it?

plush bramble
#

alright i don't understand what you're asking for then since you said you don't understand the modulo part.

barren arrow
#

with these test cases i am getting the wrong answer

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for the last one

plush bramble
#

you haven't shown your work for the formula so no way telling it's right or wrong

flint basalt
#

i think that's because it overflows the long type

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assuming this is java, long has a maximum limit of 2^63 - 1

flint basalt
#

,rccw

jolly parrotBOT
barren arrow
#

i know that we have to use some modular properties in this question to prevent overflow but i dont seem to understand which one

#

read an article as well

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didnt get what this means

plush bramble
#

you should learn some of these then

#

In mathematics, modular arithmetic is a system of arithmetic operations for integers, differing from the usual ones in that numbers "wrap around" when reaching or exceeding a certain value, called the modulus. The modern approach to number theory using modular arithmetic was developed by Carl Friedrich Gauss in his book Disquisitiones Arithmetic...

flint basalt
#

hmmm

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so it looks like you should multiply by the mod inverse

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dividing by 6 should be equivalent to multiplying by 166666668L % MOD

barren arrow
barren arrow
lusty jacinth
#

<@&268886789983436800>

barren arrow
#

😭

flint basalt
#

so we need a number $x$ such that $6x \equiv 1 (\mod 10^9 + 7)$

jolly parrotBOT
flint basalt
#

<@&268886789983436800>

barren arrow
#

how to solve this?

#

x is the modulo inverse, right?

flint basalt
#

so basically it's saying that 6x and 1 give the same remainder when divided by 1e9 + 7

plush bramble
#

In mathematics, Bézout's identity (also called Bézout's lemma), named after Étienne Bézout who proved it for polynomials, is a theorem which relates two arbitrary integers with their greatest common divisor. The theorem's statement is as follows:

Here the greatest common divisor of 0 and 0 is taken to be 0. The integers x and y are called B...

In mathematics, particularly in the area of arithmetic, a modular multiplicative inverse of an integer a is an integer x such that the product ax is congruent to 1 with respect to the modulus m. In the standard notation of modular arithmetic this congruence is written as

    a
    x
    ≡
    1
    
    ...
flint basalt
#

so you can set it up like $6x = 1 + k(10^9 + 7)$

jolly parrotBOT
barren arrow
barren arrow
flint basalt
#

go ahead and read the articles reimann sent, it'll probably explain it better than i can

barren arrow
#

okay, thank you so much for the help!

plush bramble
#

you can probably find the algorithms that implement them elsewhere. wiki just explains what the code is doing and where it comes from

pearl pondBOT
#

@barren arrow Has your question been resolved?

pearl pondBOT
#
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barren arrow
#

.reopen

pearl pondBOT
barren arrow
#

because tbh i understood very little

flint basalt
#

sure

flint basalt
barren arrow
flint basalt
#

if you set x equal to that number 166666668, then for k = 1 you get:

#

$6(166666668) \equiv 1000000008$

jolly parrotBOT
flint basalt
#

which then gets you to $1000000008 \equiv 1$ when simplifying, since you have $1000000008 = 1 + 1(1000000007)$

jolly parrotBOT
flint basalt
#

so that 166...8 is the mod inverse of 6

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and if you're wondering why we chose k = 1, it would give the smallest positive solution which therefore would give the smallest positive mod inverse

#

for k, only values where k equiv 1 would work, so 1, 7, 13, etc

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so you theoretically could choose k = 7 but it would just be a larger number

barren arrow
#

okay i understand this but how do we calculate the value of 166666668 in programming? is it (1 + 1e9 + 7) / a?

flint basalt
#

yeah i think you can do that

barren arrow
#

also is there anything else that would help me solve problems like these in future?

pearl pondBOT
#

@barren arrow Has your question been resolved?

flint basalt
barren arrow
barren arrow
flint basalt
#

my moms worked as a software engineer for decades so i've learned a lot of java programming from her

flint basalt
#

you as well keep it up! you're doing great right now

pearl pondBOT
#

@barren arrow Has your question been resolved?

pearl pondBOT
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woven river
#

they really need to specify "harder" huh

woven river
#

current progress

#

how am I supposed to get f'(1/2) in the end

#

I will continue work on this, please ping to call me back, thanks

plush bramble
#

You can pick c to be 1/2 in Taylor's expansion

#

And x = 0 and 1 as well

woven river
#

a

woven river
summer kernel
#

the Rolle theorem is not needed

woven river
#

ok, I just wrote what I thought at that time

#

ok ok

summer kernel
#

x can be fixed as long as x ∈[0,1]

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taylor expansion holds for any point x

woven river
#

I thought taylor theorem said "for every x"

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update

#

I can sense im getting closer here

#

I can see A/4

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I can see f'(1/2)

summer kernel
#

let x = 0 and x = 1

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you'd better write the remainder

woven river
#

isn't the remainder the one with f"(c)

summer kernel
#

ok, i miss that

#

c is between 1/2 and x

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x can be smaller than 1/2

woven river
#

I thought we are supposed to generalize it by saying for every x

summer kernel
#

for every x (in this problem, x ∈[0,1] by the domain of f), the taylor expansion holds, so you can pick x=0 or x=1

woven river
#

hmm I see

summer kernel
#

problem 6 gives two special points f(0)=f(1)=0, so just let x=0 and x=1 and find their relationship

woven river
#

I found this

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seems I made a mistake somewhere, can u help check if 1 and 2 are correct already?

#

they are both derived from taylor expansion

summer kernel
#

wait

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ah, you should bound |f"(x) | ≤ A later

woven river
#

wdym later

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why

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is there smth wrong

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bro I just realized

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what u mean by doing it later

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soo annoying

summer kernel
#

if you bound by A first , ①-③ A/4 disappears

woven river
#

then we will use triangle inequality

summer kernel
summer kernel
woven river
#

I will be damned in the exam

summer kernel
#

haha, good luck

woven river
#

I think the main point to note is to pay attention to every detail on the ending

#

like there's a reason the absolute sign is there

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great, just great

#

alr thanks so much vro @summer kernel , u have been helping alot, I will take a break now, cya

#

.solved

pearl pondBOT
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swift spindle
#

Is this the right track?

pearl pondBOT
stuck berry
#

assuming you did partial fractions correctly

pearl pondBOT
#

@swift spindle Has your question been resolved?

broken moth
jolly parrotBOT
#

Roufaid

broken moth
#

not what you did

#

you should have used heaviside correctly

stuck berry
swift spindle
#

uhh

#

so

#

hm

#

yea it was ok i got it thx

#

.close

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ornate vine
#

i have the function
y = 2x + sqrt 1-x
I'm trying to find the function cutting points with the X axis
I inserted 0 into the 0 and got this function:

0 = 4x^2 + 1 - x

now I did the 5 3 in the calcuator and got 2 points, which one is correct?(the answer page says only 1 is correct which is why im asking.)

sharp sleet
#

Hi

#

can i ask my doubts here.??

ornate vine
#

yeah

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i mean

#

is free

sharp sleet
#

i need help regarding jacobian matrix

spare lark
ornate vine
#

not here then

#

yeah open a new one

sharp sleet
ornate vine
#

send your message in this channel please #help-14

spare lark
#

Yep right above the occupied help channel section there are free ones

crystal dew
#

you were just a little too late in claiming the channel

smoky musk
#

You plug them back?

spare lark
ornate vine
ornate vine
sweet junco
sharp sleet
sweet junco
ornate vine
#

??

sweet junco
# ornate vine ??

what you can do is
2x+sqrt(1-x)=0 -> 2x=-sqrt(1-x) -> 4x^2=1-x -> 4x^2+x-1=0

sweet junco
ornate vine
#

nvm

#

I see where I got it wrong

#

thank you

#

you helped alot

#

.close

pearl pondBOT
#
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neat scroll
#

This is the diagram I drew .

pearl pondBOT
wicked edge
#

,rcw

jolly parrotBOT
wicked edge
#

What are you trying to find?

neat scroll
wicked edge
#

Prove what?

neat scroll
#

Wait

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Questions didn't come

#

29th questions

neat scroll
wicked edge
#

,rcw

jolly parrotBOT
neat scroll
#

I think u didn't understand how to solve u want me to share a pic of solution?

wraith jacinth
#

-# what have u tried to do so far?

wicked edge
#

Find cosine of A.

neat scroll
wicked edge
#

Given AB and AC, you can use which trigonometric function to solve?

neat scroll
wicked edge
#

Correct.

#

$\sin{\theta} = \frac{1}{2}$

jolly parrotBOT
#

Mercury (ヤフォダ)

wicked edge
#

Which angle A is?

neat scroll
neat scroll
wicked edge
#

Now just use the definition of angle sum.

wicked edge
flat falcon
#

hi

#

How old r u guys

verbal whale
pearl pondBOT
# flat falcon hi

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

wicked edge
neat scroll
verbal whale
pearl pondBOT
wicked edge
#

Alberto, you are abusing factoids.

light helm
wraith jacinth
neat scroll
wicked edge
#

Then just work out the last angle, Q.E.D.

wraith jacinth
# jolly parrot

-# also for future refrence it might help to know that this is one of the most common right angle traingles-

flat falcon
#

can i help

#

?

neat scroll
neat scroll
smoky musk
#

Quod Erat Demonstrandum

#

i.e. the proof is finished

neat scroll
vestal tapir
#

it's like lmao

light helm
vestal tapir
#

joy and relief

neat scroll
wraith jacinth
neat scroll
light helm
#

just for clarity, i'm saying that isn't 30°

wraith jacinth
wraith jacinth
neat scroll
#

If we take cos a ?

light helm
#

cos(what) = 1/2

neat scroll
light helm
#

that wasn't a yes/no question

#

i'm asking you cos(what angle?) gives 1/2

wraith jacinth
#

look at angle C

#

imagne doing sin(c) what should angle C be as the outcome?

wicked edge
#

You are doing Cos(A) = x/2x.

#

Then Cos(A) = 1/2.

#

By solving, you said A = 60. Not 30.

#

30 is C.

#

And in that case, you use sin.

#

Which yields sin(C) = x/2x.

#

Follow by Pluto and Omeganto's statements, it is important to not mix up these angles, because it can cause horrendous outcome in your proof (No Q.E.D.).

wraith jacinth
wicked edge
#

Great choice.

neat scroll
#

It will be x/2x
1/2

#

Yes

#

So wt should my next step be ?

#

A

#

Hey

#

I was saying th method

light helm
wraith jacinth
neat scroll
#

Can anyone start fro starting I got con6

light helm
#

fro?
con6?

neat scroll
wraith jacinth
neat scroll
neat scroll
#

Confused

wraith jacinth
wraith jacinth
#

so we have this diagram here correct?

neat scroll
#

No

#

X and 2x is swapped

wraith jacinth
#

apologies ur right blobcry-

#

okayyy there we go-

neat scroll
wraith jacinth
#

okay so first things off we need to define our angles-

#

since the question tells us to prove that BAC = 2ACB

#

so we need to find each angle in this traingle-

#

well angle ABC is pretty east thats just 90 right?

neat scroll
wraith jacinth
#

okay so if we find one angle we can find the other correct?

neat scroll
#

Understood till here

wraith jacinth
#

choose an angle!

neat scroll
wraith jacinth
#

okay soo what sides DO we have in comparsion to angle A

neat scroll
#

Ab and ac

wraith jacinth
#

okay if we have AB and AC which trigemetric function can we use??

wraith jacinth
#

YUP EXACTLY!!

neat scroll
#

Cos a =1/2?

wraith jacinth
#

YES!!

neat scroll
#

A =60?

wraith jacinth
#

THATS CORRECT WELL DONE!!

neat scroll
#

C = 30 ?

wraith jacinth
#

in comparsion to C whatsides do we have?

neat scroll
wraith jacinth
#

,rcw

neat scroll
jolly parrotBOT
wraith jacinth
neat scroll
wraith jacinth
neat scroll
wraith jacinth
neat scroll
#

OK I got this method

wraith jacinth
wraith jacinth
neat scroll
neat scroll
wraith jacinth
wraith jacinth
wraith jacinth
neat scroll
wraith jacinth
#

now draw line DB

neat scroll
wraith jacinth
neat scroll
wraith jacinth
neat scroll
wraith jacinth
# wraith jacinth

now since angle A is 60 degrres and traingle ADB is issocles that means that means that all angles are 60

#

do that means traingle ADB is equalateral-

wraith jacinth
#

so ADB becomes equlateral and BDC becomes isosles

wraith jacinth
wraith jacinth
#

apperently its using a semi circle-?

neat scroll
wraith jacinth
#

okay so u draw circle with center D and we use X as the radius

#

now because X is the radius u will hit point A and C on the circle

#

OHH I SEE-

#

OKAY OAKY i get it now-

neat scroll
#

Reason?

wraith jacinth
neat scroll
wraith jacinth
#

okay so look at this circle

#

the radius here = X right?

wraith jacinth
neat scroll
wraith jacinth
#

now notice how ANYTHING u draw on it IF it has an angle of 90 it will be a point on the circle?

wraith jacinth
wraith jacinth
#

so both sides add up to 2x

#

and remeber how the equation of the circle is basssicly

#

x^2 + y^2

#

pythagerom therom is bassicly

#

c^2 (diaamter = x^2 + y^2

#

bassicly it uses the fact that ANY point on the circle connected tothe DIAMATER will always be 90 degrees-

neat scroll
wraith jacinth
wraith jacinth
neat scroll
wraith jacinth
neat scroll
#

Applies *

neat scroll
wraith jacinth
wraith jacinth
#

because reember if the circle we have touches point A it means the radius = x so it toch B too means DA = X

#

and from that fact we knwo that ADB is an equliateral traingle-

#

does that make sense?

neat scroll
neat scroll
wraith jacinth
wraith jacinth
wraith jacinth
neat scroll
#

Yesss

#

I visulaizwd It thanks

wraith jacinth
#

DO YOU SEE IT-

#

SO BECAUSEEEEEEE ABC is 90 DEGREES-

#

WE CAN CONCLUDE THAT DB = X

#

does that make sensee????!!!

neat scroll
wraith jacinth
neat scroll
wraith jacinth
neat scroll
wicked edge
#

Why angle B is written as "b" here?

neat scroll
#

I got it now

wraith jacinth
neat scroll
wraith jacinth
#

1 sec lemem fix it-

neat scroll
wraith jacinth
#

and the rest is history-

#

alsthough using sin and cos is so much easeir 😭

#

here^

neat scroll
#

Oh leave I got ittt

wraith jacinth
neat scroll
#

Thanks

wraith jacinth
#

yeah you get it!

#

ALRIGHT GOODLUCKKK! CYA!!

#

-# dont forget to .close when ur done catlove

neat scroll
#

Cya ?

neat scroll
wicked edge
# wraith jacinth

Using the properties of the perpendicular bisector and by the definition of circle here is alright, but isn't is quite tedious?

wraith jacinth
# neat scroll Next time can I dm u for solutions ? U explained so easily?

welllll u can ping me here and if i am online i will respond!! its better to ask here because i can make mistakes and other helpers bieng there to help when i do one its good also if i ever have to leave or i am busy someone else can respond!! but feel free to ping me and i will try to come if i can!!

wraith jacinth
wraith jacinth
wicked edge
#

Yeah, OP should stick to sine and cosine, although it is correct, but a shorter way is much better.

neat scroll
wraith jacinth
wicked edge
#

Great help from Pluto anyways.

neat scroll
wraith jacinth
wicked edge
#

Yeah that one is good, but the circle is no need here right, a bit redundant.

sharp delta
#

What was the question

wicked edge
#

(In my opinion), since you can just define the midpoint on hypotenuse, then reasoning that by the definition of the perpendicular bisector in right triangle, ->.

neat scroll
#

I drew this diagram

wraith jacinth
neat scroll
#

@wraith jacinth

jolly parrotBOT
wraith jacinth
neat scroll
sharp delta
wraith jacinth
neat scroll
#

I am solving 30th now

neat scroll
wraith jacinth
# wraith jacinth

okay so first things off it tells us that B = C which is equa to 2A

#

from that fact alone we can find each angle in the traingle

#

because well they all add up to 180

sharp delta
#

Use trigonometry I suggest

neat scroll
#

5x =180
X =36?

#

How does this helps as it's nt standard angle

wraith jacinth
#

okay lemme see-

wraith jacinth
#

so knowing that we know which angle = 36?

#

and which angles are equal to 2(36)?

neat scroll
#

B and c

wraith jacinth
#

so b and c are = 72 correct?

neat scroll
#

Yes

wraith jacinth
neat scroll
wraith jacinth
#

actally there is 2 methods to prove this

neat scroll
wraith jacinth
delicate temple
wraith jacinth
delicate temple
#

Whats the problem?

wraith jacinth
wraith jacinth
wraith jacinth
delicate temple
neat scroll
wraith jacinth
#

also wait sorry-

#

i wrote slight mistake

#

tis 36 NOT 32

neat scroll
wraith jacinth
#

okay so knowing this try to find andlge BDC

#

the one in blue!

neat scroll
#

72

wraith jacinth
neat scroll
#

Yes

wraith jacinth
#

now try to find angle ADB

neat scroll
#

108

wraith jacinth
#

okay so knowing all of the angles can u think how we can prove that AD = BC?

#

-# hint ||think of isosles traingles||

neat scroll
#

Ad =bd
Bd =bc
Ad =bc

#

So thansk

#

Byeee

wraith jacinth
#

YUP well DONEEE!!!

neat scroll
#

Thanks uuuu

wraith jacinth
#

BYEEEE catlove

neat scroll
#

Loves u 💓

#

Byeeee

wraith jacinth
#

-# dont forget to .close!!

neat scroll
#

.close

pearl pondBOT
#
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quick venture
pearl pondBOT
quick venture
#

hi for this integral

timber cape
#

hmmm

quick venture
#

why isnt it what i've written in red?

torn flicker
#

um

#

lcm should be (x + 1)^2 (x -1 ) right?

rose lark
torn flicker
#

so you just need to multiply by x - 1

fleet ridge
#

When you multiply everythign with "(x + 1)^2 (x -1 )", the "(x + 1)^2" gets cancelled

timber cape
past perch
# quick venture

the fractions when reformed need to have the same LCM (or denominator) as the LHS.

the B term already has (x+1)^2, so to match the lhs it only needs an (x-1)

to contrast, the A term has only (x+1) thus it needs one (x+1) AND one (x-1) to give the required LCM

#

remember that when you're taking an LCM you're not just multiplying the numerator, but also the denominator

1/2 + 4/5 becomes (5+8)/10 because the 1/2 becomes 1*5/2*5=5/10 (same for the other fraction and then addition is possible) and thus stays the same overall ratio

#

if you multiply the B term like you did in red you're basically doing numerator times (x-1)(x+1) AND denominator too, which becomes redundant

quick venture
timber cape
#

-# sam beam for a reason

pearl pondBOT
#

@quick venture Has your question been resolved?

#
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#

Please don't occupy multiple help channels.

errant solstice
#

<@&268886789983436800>

sterile python
#

<@&268886789983436800>

pearl pondBOT
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sterile python
#

Fast one Chiaki catgiggle

timber cape
#

damn

errant solstice
#

speed doesn't matter when... never mind.

sterile python
errant solstice
fading cove
#

yo guys can u helm me with thi s math question

sterile python
errant solstice
#

in help channels.

wraith jacinth
sterile python
#

I do not understand that term... :((

errant solstice
#

not even getting sniped sometimes. just straight up ramboed into a channel I'm helping.

#

but never mind. not a rule anyway. and as long as helpees get the help they need, I suppose.

prime bramble
sterile python
light helm
#

This is not the channel you're looking for.
Move along.

errant solstice
#

sorry, got a little carried away.

sterile python
#

Omeganto

pearl pondBOT
#
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steady dagger
#

So basically i was working on application of shm using complex numbers
Yk
X= xmax* e^itheta
I was required to find the angle,
Which i got by equating both sin and cos imaginary part with sin and real part with cos
Cos inv gave 17.58degrees
Sin inv gave -17.58 degree
Tan of both RESPECTIVE angles
Gave -17.58
Which one to write? Im confused
P.s attaching the yt video ss i got here, in which the teacher gets 17.58 if u calculate sin^inv....
HELP

steady dagger
#

The second picture is ss from yt, i was looking for solution but i found that the value is same in magnitude but my -tive when I take tan

#

Which one to

#

Write can anyone help

feral olive
#

Do you know the unit circle

steady dagger
feral olive
#

Pretty much the absolute value of the angles you are getting is the reference angle

#

You need to find the quadrant of the unit circle where cos is positive, sin is negative and tan is negative

steady dagger
feral olive
#

Idk how it works for u but in this situation i just draw the circle with the CAST rule in the quadrants and circle which quadrant corresponds with the results

steady dagger
#

Or instead of taking tan i could like completely neglect imaginary sin and go with cos inverse only to find the angle

terse blaze
#

hi

steady dagger
terse blaze
#

nothing much

feral olive
#

Or are you saying to take the real value only since its SHM

steady dagger
steady dagger
feral olive
#

I guess you would only use cos since that marks the position of the object

steady dagger
#

Why is ts so hardopencry

pearl pondBOT
#

@steady dagger Has your question been resolved?

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acoustic tangle
pearl pondBOT
acoustic tangle
#

For part a I tried using this method

#

17/4 =4.25

#

Round up to 5

#

So the fifth value which is 63

#

But the markscheme is 61

pearl pondBOT
#

@acoustic tangle Has your question been resolved?

dense jasper
jolly parrotBOT
#

Civil Service Pigeon

acoustic tangle
dense jasper
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remote saffron
#

What should be the thinking process for solving this type

brisk steeple
#

,rotate

jolly parrotBOT
brisk steeple
#

(3) is easy. You can just input the values.

fleet ridge
#

I think because there is a lot of sin^2 and cos^2, you'll look to use the identity sin^2x+cos^2x=1

remote saffron
#

Should I covert into cos² using sin²x= cos²(90-x)

fleet ridge
remote saffron
#

3

jolly parrotBOT
#

Ultimator

wraith hinge
#

same for cos

fleet ridge
brisk steeple
#

Interestingly, the value of (4) is 2

#

Just observe that pi/8 = pi/2 - 3pi/8
So cos^2 (pi/8) + cos^2 (3pi/8) = cos^2 (pi/2 - 3pi/8) + cos^2 (3pi/8) = sin^2 (3pi/8) + cos^2 (3pi/8) = 1

remote saffron
#

I see

#

But what about the last 2 terms?

brisk steeple
#

cos^2 (pi/8) = cos^2 (7pi/8) and cos^2 (3pi/8) = cos^2 (5pi/8)

remote saffron
#

How

fleet ridge
brisk steeple
#

Use the fact that cos(pi-x) = -cos(x)
Now square both sides

pearl pondBOT
#

@remote saffron Has your question been resolved?

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pearl pondBOT
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grand mountain
#

@dense jasper

pearl pondBOT
grand mountain
#

I just wanna make sure this is the correct answer for SVD right

plush bramble
pearl pondBOT
grand mountain
#

My bad

wicked edge
#

What is the original question?

grand mountain
#

We've learned about matrix diagonalization, which is a type of matrix decomposition. There are some others that we must learn, including LU decomposition, Cholesky decomposition, QR decomposition, and singular value decomposition. Let's get a closer look!

Script by Lorcan Nicholls

Watch the whole Mathematics playlist: http://bit.ly/ProfDaveMat...

▶ Play video
pearl pondBOT
#

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inland laurel
pearl pondBOT
inland laurel
#

How to solve this paragraph

#

Let's solve this together

honest oyster
#

Did you make any progress

inland laurel
#

yeah

#

i am sending it in a min

#

we want a smart approach this is not a smart one

honest oyster
#

I think it's better if we first find out which value f(x) will output for any given input

#

So comparing x-[x] and -x-[-x]

tame prism
#

What is the question??

honest oyster
#

10 and 11

tame prism
inland laurel
tame prism
#

So basically what is the trouble u are faciny

inland laurel
tame prism
#

So basically I think creating 2 cases is the approach x is -ve and x is +ve

pearl pondBOT
#

@inland laurel Has your question been resolved?

cyan heron
# inland laurel

Are the answers B and A?
If yes, i recommend drawing the graphs of these functions as a hint
If not, ive probably done something wrong

pearl pondBOT
#
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sharp smelt
pearl pondBOT
sharp smelt
#

I'd like to solve this using the trapezoidal rule first

#

so $\frac{1}{2} (f(0)+f(1))$?

jolly parrotBOT
#

what a wonderful world(wai)

sharp smelt
#

so $\frac{1}{12}\left(\frac{1}{12}+ \frac{1}{13}\right)$

jolly parrotBOT
#

what a wonderful world(wai)

sharp smelt
#

As for simpson's rule

#

I'll have to consider the lagrange polys of the 2nd, 4th and 8 degrees?

smoky gull
sharp smelt
#

uh

#

$\int_{0}^{\frac{1}{2}} \frac{ (x-0.5)(x-1)}{0.5} \cdot \frac{1}{12} + \frac{(x)(x-1)}{-0.25} \frac{1}{12.25} + \frac{(x)(x-0.5)}{0.5} \frac{1}{13} dx$

jolly parrotBOT
#

what a wonderful world(wai)

sharp smelt
#

as obtained by interpolating the function using lagrange interpolation

#

I'll do the one for 5 point as 9 is too painful

#

or am I supposd to use the formula

pearl pondBOT
#

@sharp smelt Has your question been resolved?

humble lintel
#

I'm not sure what you are doing here, Why do you have all these terms inside of the integral

sharp smelt
humble lintel
#

Okay, but do you understand what SImpsons rule does

sharp smelt
humble lintel
#

And how that is different from Riemann integration

sharp smelt
#

isn't

#

right

humble lintel
#

What is osm?

sharp smelt
#

typo

#

I meant to type isn't

humble lintel
#

What do you mean by isn't

sharp smelt
#

It's the same

#

is it not

#

like we're approximating the function via a polynomial

humble lintel
#

I don't really see them as the same thing, but moving past that for a moment, you take a Riemann sum to replace an integral

#

So I don't see why you are trying to change your integrand doing this instead of just applying the result

sharp smelt
#

so use the sum instead

humble lintel
#

Well, you can do what you are doing now instead if you want, but this is a bad idea because you are essentially reproving the formula for no good reason in the middle of the calculation.

sharp smelt
#

One more question

#

for the 5 and 9 point cases

#

would I use simpson's composite 1/3rd rule

#

or the composite 3/8 rule

humble lintel
#

I don't know what terminology your class uses. When I think "Use Simpson's rule" I think use the 1/3 rule by default and this phrasing is ambiguous

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Frankly, if I were in your position, I would just do and submit both. It really isn't that much extra work

sharp smelt
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noted

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thanks!

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.close

pearl pondBOT
#
Channel closed

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Use .reopen if this was a mistake.

sharp smelt
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.close

pearl pondBOT
#
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iron schooner
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why is angle A2 = to 20 degree I dont understand, and what is angle O3?

brazen hare
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are isoceles

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so angle B and angle A will be same

iron schooner
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so angle O3 is 30 degrees and angle A2 is 50 degrees?

brazen hare
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look at OAB

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B1 and a(1+2) are equal

iron schooner
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could you visually show me a image?

iron schooner
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angle A 1 is 30 degrees

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and angle B 1 is 50 degrees

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those angles are both in different triangles

brazen hare
iron schooner
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now what do we need to do?

sacred python
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what are you guys trying to find

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i think i can help

iron schooner
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my question: why is angle A2 = to 20 degree I dont understand, and what is angle O3?

sacred python
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is o2 given

iron schooner
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based on this image below

sacred python
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so we dont know o2

iron schooner
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no we dont

sacred python
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angle c is 30

iron schooner
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how is angle c 30 they never said anything is parallel?

sacred python
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in triangle coa it is isosclelene

iron schooner
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ohh

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yess

sacred python
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similarly angle a is 50

iron schooner
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yea i can see that

sacred python
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so angle a2 = 50-30

iron schooner
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ok so angle C1 is 50 degrees

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hold on

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30*

sacred python
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yes

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exactly

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you see in triangleoab\

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oab is isoscelene

iron schooner
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wait now what is after that?

sacred python
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so angle a=b=50

iron schooner
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= sides opp = angles right?

sacred python
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ya

iron schooner
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so its angle A2 of the whole angle A?

sacred python
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so angle a2=50-a1

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no

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look

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b=a

iron schooner
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show me a image?

sacred python
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i dont have one

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its just the thing you gave

iron schooner
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ok wait lets do it step by step then hold on

sacred python
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dude you dont need steps its just mental math

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we now know a and b dont we

iron schooner
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yes

sacred python
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yes now find o3

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using angle sum property it will be 80

iron schooner
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wait

sacred python
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joey are you confused

iron schooner
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its angle A 1 = 30 degrees

sacred python
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ya

iron schooner
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not the whole angle A

sacred python
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no A=50

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so now a2 is 20

iron schooner
#

look at the given

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its says A1

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= 30 degrees

sacred python
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yes a1+a2=a

iron schooner
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but we dont know a2?

sacred python
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30+a2=50

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we know a1 and a though

iron schooner
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whats the reason for that?

sacred python
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now a2 is 20

iron schooner
sacred python
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cus a1=30 and a=50

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no formulas

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just simple logic

iron schooner
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I need a reason for that?

sacred python
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look at the image once

iron schooner
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we cant just pull it out the air?

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30 + a 2= 50?

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whats the reason

sacred python
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dude just look at the picture

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we know that a=50 right

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we just found it out

iron schooner
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= angles opp = radii?

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that surely cant be the reason

sacred python
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dude forget about the circle

iron schooner
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im looking for the reasons

sacred python
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focus on the triangle

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oa and ob are radii

iron schooner
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even without the circle it would be = angles opp = sides

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which cant be the right answer bc it 50

sacred python
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oa = ob

iron schooner
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lit could be a2 = 50.

sacred python
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no

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listen

iron schooner
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lets us find A2 first

sacred python
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wait

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for that we need to prove oab is a isosceles triangle

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now tell me looking at the pic if it is or not

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so then obviously a1+a2=b