#help-10

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fathom flicker
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obtuse pebbleBOT
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wooden obsidian
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The line y = x+1 intersects the curve y = x^2 +x-3 at 2 points.Find the coordinates of the 2 points

obtuse pebbleBOT
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stone forge
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hi

obtuse pebbleBOT
stone forge
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i just have a question

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you know how you conjugate when u wanna verify trig identities sometimes

zenith raft
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lmfao

stone forge
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im using the channel

fathom flicker
obtuse pebbleBOT
stone forge
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also wtf is that banner

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this generation 🤦‍♂️

zenith raft
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what generation

stone forge
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get out

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i need help with my trig identities

zenith raft
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you haven’t even posted a question dawg

stone forge
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yes i have

zenith raft
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just body shamed me…

stone forge
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but ur stupid messages have covered it up

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yeah surely i did

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get out

high lily
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you know how you conjugate when u wanna verify trig identities sometimes
yes.
conjugates are relevant in many questions related to verifying identities

stone forge
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im not sure on when you are supposed to conjugate

high lily
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consider
c^2 = a^2 + b^2
c^2 - a^2 = b^2
(c-a)(c+a) = b^2
conjugates will usually be helpful if you have (c-a) or (c+a) present

stone forge
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ah i see

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wait do you have any examples perchance

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in trig identities

dense imp
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I guess one example I can think of is if you think back to difference of 2 squares: x^2 - y^2 = (x + y)(x - y)
there are some trig identities that involve sums or difference of two squares, like for example
cos^2 x - sin^2 x = cos 2x

maybe you see you have (cos x + sin x) and you think you might wanna transform that for some reason into cos 2x and you multiply both sides by (cos x - sin x) to get the above identity and be able to apply it.

you might also be able to apply stuff like sin^2 x + cos^2 x if you move quantities around from one side to the other of the equation and signs are changing, so i'd say if you are familiar with the couple basic identities that involves differences and squares of sums you can often "smell these out"

fathom flicker
stone forge
zenith raft
stone forge
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i had a feeling someone was gonna say smth ab that

stone forge
dense imp
obtuse pebbleBOT
stone forge
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can i just say ima conjugate when when it looks like this

obtuse pebbleBOT
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@stone forge Has your question been resolved?

high lily
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conjuate when a pythagorean trig identity is applicable/relevant

stone forge
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i think i got it

#

ty

obtuse pebbleBOT
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fluid snow
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Find the inverse of $f(x) = \frac{3x}{2x^2 - 18}$. So we have that \begin{align*} \frac{3x}{2x^2 - 18} &= y \ 3x &= y(2x^2 - 18) \ 3x &= 2y(x + 3)(x - 3)\end{align*} but all this doesn't seem very helpful

fluid snow
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I also thought about dividing by x right away

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But having $\frac{3}{2x - \frac{18}{x}}$ doens't seem very helpful either

haughty coyote
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Just expand
It's a quadratic in x

fluid snow
fluid snow
haughty coyote
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You wrote 3 lines of computation
You can find where

fluid snow
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$3x = 2x^2y - 18y$

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You must mean that?

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Hm

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Oh, so you'd just solve for x with the quadratic formula?

frank dome
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yeah

fluid snow
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Alright, thank you

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fluid snow
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.reopen

obtuse pebbleBOT
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fluid snow
# frank dome yeah

So I got $\overline f(x) = \frac{3 \pm 3\sqrt{1 + 16x^2}}{4x}$. So here, we don't have to decide which one to pick, the $+$ or $-$ version?

fluid snow
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So did we really find the inverse?

frank dome
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if you mean the domains dont match, then they arent supposed to. the domain of a function is the range of its inverse function

fluid snow
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But 0 is not in the range

fluid snow
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A function maps an x-value to a single y-value

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Not two

frank dome
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if you conssider the limit

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then f^-1 (0) = 0

frank dome
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since the range of f^-1 would then have to be the domain of f

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and also if you consider that domain of f then it doesnt have 0 in its range either, and f^-1 doesnt have 0 in its domain either, so it matches

fluid snow
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(-3, 3) is missing

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,w range (3 - 3sqrt(1 + 16x^2))/(4x)

frank dome
fluid snow
fluid snow
frank dome
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ah

fluid snow
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It'd be f(0) = 0/-18 = 0

frank dome
fluid snow
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So 0 should be in the domain of f

frank dome
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my bad

fluid snow
frank dome
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well if your original function isnt 1-1, your inverse wouldnt be either, now, would it?

fluid snow
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And I determined R \ {3, -3}

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Maybe that's wrong?

frank dome
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if you exclude the entire (-3,3) interval then the function is 1-1

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but right now it isnt

fluid snow
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$f'(x) = -6 \cdot \frac{x^2 + 9}{4(x+3)^2(x-3)^2}$ I got

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And that's negative on its entire domain

frank dome
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decreasing is not the same as 1-1

fluid snow
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So f is 1-1 there

fluid snow
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Oh wait

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The -3 and 3 cause the problems here

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It "jumps up"

frank dome
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it has a discontinuity at x = -3, for example, so it can go back up and decrease from a high value

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yes

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that's why i thought you excluded the whole interval

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since that makes it 1-1

fluid snow
frank dome
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it removes the part where the function "jumps up" and decreases from a high value

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so now it just purely decreases the entire time

fluid snow
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So you imagined its graph?

frank dome
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think of it's behaviour just before -3 and just after 3

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highly negative before -3 and highly positive after 3

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so it jumps from decreasing and negative to decreasing and positive

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implying it is 1-1

fluid snow
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Maybe using $f(x_1) = f(x_2)$

frank dome
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ig after you show f is decreasing you can just show that f is negative for x < -3 and positive for x > 3

fluid snow
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$\frac{3x_1}{2x_1^2 - 18} =\frac{3x_2}{2x_2^2 - 18}$

frank dome
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this looks unnecessarily painful

fluid snow
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Ok, thanks

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cunning flower
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$U_0=2 \ U{n+1}=\frac{1}{U_n}+\frac{U_n}{2}
\text{prove that }\forall \ n \ in \ \mathbb{N} \ U_n>\sqrt{2}}$

warm shaleBOT
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brahim3579
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cunning flower
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how can i slove it

solar meadow
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How can there be $U_0$ then?

warm shaleBOT
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Roman_Garland

cunning flower
solar meadow
cunning flower
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Natural numbers

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its the symbol

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<@&286206848099549185>

solar meadow
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then n cannot be 0?

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Bc Natural numbers starts with 1?

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does it start with 0 in here?

cunning flower
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its always start with 0

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0 is a decimal number? absolutely not

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$U_0=2 \ U{n+1}=\frac{1}{U_n}+\frac{U_n}{2}
\text{prove that }\forall \ n \ in \ \mathbb{N} \ U_n>\sqrt{2}}$
someone can helps here

warm shaleBOT
#

brahim3579
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cunning flower
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<@&286206848099549185>

solar meadow
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Prove that U_n is always less than sqrt(2) and then is always equal to sqrt(2)

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@cunning flower

obtuse pebbleBOT
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@cunning flower Has your question been resolved?

obtuse pebbleBOT
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slender lily
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Can someone please help me with this question (it’s translated from German to English and there is a picture which shows the graph needed) Fig. 1 shows the graph of the derivative function f' of a function f. Which of the following statements are correct? Justify your answers.

A: The function f is monotonously falling in the interval [0; 2].

B: The function f has at the point x = - 1 a

Extremum.

C: The graph of f has a low point and a high point.

D: For all x in the interval [- 2; 0] applies f (x) > 0.

E: The function f" meets the X-axis at the point x = -1

slender lily
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If possible can you explain how to do in future problems

fluid snow
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B: Was musst du denn prüfen, um herauszufinden, ob irgendwo ein Maximum oder Minimum vorliegt? ||Notwendige Bedingung: f'(x) = 0 + Hinreichende Bedingung: f''(x) > 0 bzw. f''(x) < 0 oder Vorzeichenwechsel von f'||

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C: analog zu B

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D: Welche Information geht beim Ableiten "verloren"? Denk an f(x) = x + 10000000 -> f'(x) = 1

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E: Was bedeutet die Ableitung? f'' ist ja nur die Ableitung von f', was gegeben ist

slender lily
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Wie darf ich verstehen, dass die Ableitung Negativ oder Positiv ist, also von der X-Achse gesehen negativ oder wie? (Bezüglich A)

fluid snow
slender lily
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Würde also f(x) so aussehen?

fluid snow
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Z.B. könntest du mit x^2 + 100 anfangen, die Ableitung ist dann 2x und wenn du dann versuchst, nur anhand 2x wieder auf die Originalfunktion zu kommen, hast du x^2, aber die + 100 ist verlorengegangen

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Daher sagt man + C beim integrieren

fluid snow
slender lily
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Ich weiß aber ich habe keine Ahnung wie man aus der Ableitung der Ursprungs Funktion Informationen entnimmt, dass ist mir jetzt deutlich klarer geworden. Die Lösungen haben wir nämlich auch nichts gebracht.

Und noch eine Frage zu E warum hat f“(x) eine nullstelle bei -1?

fluid snow
fluid snow
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Du kannst ja mal versuchen, die Sachen, die ich am Anfang geschrieben habe, durchzugehen und wenn etwas unklar ist, kannst du ja fragen

slender lily
#

.close

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fading herald
obtuse pebbleBOT
fading herald
#

What’s happening with my inequality? I’m messing it up

fluid snow
fading herald
fluid snow
fading herald
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yeah

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determine domain

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what i did is x > -3

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but thats wrong

fluid snow
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,w domain (x-4)/(sqrt(x^2 + x - 6))

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Ok, the solution is right, let's see where the mistake is

fluid snow
shadow knoll
fluid snow
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Both could be negative

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And it'd turn positive

fading herald
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and never covered it

fluid snow
fluid snow
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(x+3)(x-2) has its zeros at x = -3 and x = 2

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And it's opened upwards

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So it will be positive on (-infty, -3) and on (2, infty)

fading herald
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ok let me think

fading herald
fluid snow
fading herald
shadow knoll
fluid snow
fading herald
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i see thanks guys

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you can close the channel now

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i forget how to

shadow knoll
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.close

fading herald
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.close

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fluid snow
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Am I not showing my working here?

fading herald
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ok gotcha

fluid snow
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Unless your teacher told you to do it algebraically

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(in which case you could tell him this way is faster when you have a quadratic and he should allow you to use this..)

obtuse pebbleBOT
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stray timber
obtuse pebbleBOT
stray timber
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is my work correct?

tender stratus
stray timber
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why?

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i put (0,0) into the derivitive

hexed needle
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put (0,0) in the final equation, it's not resulting a 0

stray timber
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am sorry but am kind of confused wht u mean>

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<@&286206848099549185>

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paper swan
#

On the sides AC and BC of a triangle ABC, isosceles on the base AB, consider two points P and Q respectively, such that the angle CPQ is equal to the angle ABC. just need help with this really quickly

teal ledge
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What do you have to get for the result?

undone yoke
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@paper swan

paper swan
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that it is parallel

undone yoke
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What is parallel ?

paper swan
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oh mb it didn't send the whole question

teal ledge
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you mean AB and PQ is parallel?

paper swan
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yes yes

teal ledge
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should they have to?

paper swan
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yes they shold be parallel

teal ledge
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please show me the full question

undone yoke
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It seems

paper swan
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yeah prove that it is parallel

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drawing

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like this i guess

undone yoke
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Good. Observe that angle C is common for both.

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Then angle CQP and angle CAB are also equal.

teal ledge
undone yoke
undone yoke
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If the other set of angles was not equal, we couldn't have said anything.

paper swan
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mhh

undone yoke
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They basically wouldnt have been parallel.

paper swan
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would you have been able to do it without the drawing or nah

undone yoke
# paper swan mhh

I would have been. The question gave me enough data to be able to draw it myself.

paper swan
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yeah but what if you couldn't draw it

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my prof tells us that the drawing is there just to understand and you can't prove it just by observing the drawing but gotta write the proof

undone yoke
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Tell your professor, in geometry, a drawing always comes first, even without the provision of data. Then comes the data itself.

paper swan
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okok

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could you help me out with this one

teal ledge
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I think angle CQP is same as angle CBA is enough for parallel-ness

undone yoke
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No. What is CPQ was not equal to CAB ?

teal ledge
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they are corresponding angles

undone yoke
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Then the lines would be intersecting. See @paper swan this is why figures are important.

iron edge
paper swan
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so how anout this one

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In a triangle ABC, let BP be the bisector of the angle B. From P draw the parallel to BC; call Q the point in which meet the side AB. Always from P draw the parallel to AB until it meets the BC side. Prove that the triangle PBQ is congruent to the triangle PBR

undone yoke
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Okay don't give a figure now.

paper swan
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alright

teal ledge
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what is R

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PR with BC?

undone yoke
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Yeah exactly.

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How is it made ?

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Perpendicular subtending. Random intersection?

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How is it?

paper swan
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r is the point that meets CB

teal ledge
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then PR is parallel to AB?

paper swan
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yes

undone yoke
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,rcw

warm shaleBOT
undone yoke
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@paper swan

teal ledge
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with BP in common

paper swan
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oh they're congruent because all their angles are?

teal ledge
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should include that BP is in common, so ASA congruence

teal ledge
undone yoke
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Haa that'll be there due to the isosceles property. But we were discussing what if it wasn't isosceles ?

paper swan
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yeah in the first question it is given it is isosceles

paper swan
teal ledge
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I think the focus of what I was talking is different from what you understanded as. My fault, I am sorry

teal ledge
paper swan
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If two lines cut by a transversal form with it:
two alternate (internal or external) equal angles, or
two equal corresponding angles, or
two additional conjugate angles (internal or external),

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the two linesa re parallel

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i learned this

teal ledge
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I am not 100% sure on what solomaniac wanted to say, but I think he wanted to show that CPA=CAB and CQP=CBA

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What I wanted to say is as CQP=CBA, two lines are parallel because they are two corresponding angles, and they have same angle

paper swan
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yeah the two lines are parallel because when cut with a transversal they form equal corrisponding angles

teal ledge
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I think me and solomaniac had different axiom to show parallel-ness

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no big problem I guess

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Sorry for confusion again.

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@paper swan Do you have any other questions?

paper swan
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yes

paper swan
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and what else to determine they're congruent?

teal ledge
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Can you explain ASA congruence?

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Or do you know about ASA congrunence?

paper swan
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yeah when two triangles have a side in common and the two angles on that side are congruent

paper swan
teal ledge
# warm shale

To add more QBP is same as RBP because BP is angle bisector

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So QBP=RBP, BP in common and QPB=RPB

paper swan
teal ledge
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because BP bisects angle QBR

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which means QPB and RPB should both be half of QBR

paper swan
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so because they form alternate internal angles?

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or that doesn't have anything to do with it

teal ledge
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oh sorry typo issue

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QBP and RBP both should be half of QBR

paper swan
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ah okay okay

teal ledge
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Actually you dont have to say QBP=RBP for congruence

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not necessary

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QBP=RPB(alternal angle), QPB=RBP(alternal angle) and BP in common

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so two angles, and side between those two angle is all congruent

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which means ASA congruence for triangle

paper swan
teal ledge
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yes

teal ledge
paper swan
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not of the angle p

teal ledge
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But as question is asking for PBQ and PBR, using bisection is appropriate now I think

paper swan
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what do you mean?

teal ledge
paper swan
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yes

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bp is the bisector of angle QBR

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and it divides it in half forming two congruete angles

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but what about angle QPR

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how do you know that it is also the bisector of that angle

teal ledge
teal ledge
paper swan
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yeah but how do you know that QPB=PBR=QBP=BPR

teal ledge
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QPB=PBR for same alternate angle
PBR=QBP for bisecting QBR with BP
QBP=BPR for same alternate angle

paper swan
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ohh okay yeah now i get it

paper swan
teal ledge
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okay

paper swan
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Given two parallel lines r and t, and a transversal t that meets the line r in P and the line s in Q, draw a line through the midpoint M of PQ that meets r in R and s in S. Prove that PR = SQ

teal ledge
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Also ASA congruence

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MP=MQ

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RPM=SQP

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RMP=SMQ

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so two triangles are congruent

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whicb means PR and QS should be same in length^

paper swan
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no not the triangles

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the lines PR and SQ

paper swan
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OHH

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right

paper swan
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oh because it's the midpoint

teal ledge
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yes

paper swan
teal ledge
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alternal angle

paper swan
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ohh right

teal ledge
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they have same angle because r and s is parallel

paper swan
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you mean r and t?

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or R and S

teal ledge
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"Given two parallel lines r and s,..." in your question

paper swan
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ohh mb it was supposed to be a t

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i thought of something like this

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the angles QMS and RMP are congruent because they're opposite

teal ledge
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you are right. Only angles are not enough though. IMO It's good to look for at least one side congruence

paper swan
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ohh okay

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so if all three angles are congruent it isn't enough

teal ledge
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if all three angles are same, but dont know about sides, then you say those two triangles are similar

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but not enough for congruent

paper swan
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ohh i see

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thank you man

teal ledge
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np

paper swan
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you can close the channel now i'm good

teal ledge
#

you should

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!done

obtuse pebbleBOT
#

If you are done with this channel, please mark your problem as solved by typing .close

paper swan
#

.close

obtuse pebbleBOT
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dark idol
#

BDF r wrong

obtuse pebbleBOT
dark idol
#

Help

undone yoke
#

Yeah they are. You haven't understood what the question was asking.

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It was asking $5^+, 6^-$

warm shaleBOT
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Solomaniac

dark idol
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Ik that

undone yoke
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As for f, both the limits of $6^+, 6^-$ are going to -infinity.

warm shaleBOT
#

Solomaniac

dark idol
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It looks like 6- doesn’t even go to 1

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Same for 5+

undone yoke
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Same for 5+

dark idol
#

.close

obtuse pebbleBOT
#
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random olive
#

"(The old man in the box) A cubic box has a corner at the origin and edges OA, OB
and OC with others in the points A = (2, −2, 1), B = (1, 2, 2) and C =
(−2, −1, 2). A dot-shaped old man is at the point with coordinates
(0.9, −0.9, 4.5). Is the old man in the drawer?
Tip: Transfer to a suitable new base. Rephrase the question 'lie in the drawer' in ¨
algebraic terms. What finesse does the change to a new ON base offer?"

random olive
#

does anyone know how to solve this?

obtuse pebbleBOT
#

@random olive Has your question been resolved?

random olive
#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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dapper wing
#

why is this wrong?

obtuse pebbleBOT
dapper wing
#

pi/3 - 1 = .047

#

how do i convert that to radians

#

or is it (pi-3) / 3

obtuse pebbleBOT
#

@dapper wing Has your question been resolved?

dapper wing
#

ty

obtuse pebbleBOT
#
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#
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stray timber
obtuse pebbleBOT
stray timber
#

i am confused about this question i found the derivative

#

do i just equal the derivative to 0

brave bramble
#

You'll need to find dy/dx before anything else

#

But yeah, dy/dx = 0 at those points

stray timber
#

but i does not give me any points

brave bramble
#

Correct, you've got to find them

stray timber
#

ah ok

#

thx

obtuse pebbleBOT
#

@stray timber Has your question been resolved?

#
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#
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heavy chasm
#

how to solve this

obtuse pebbleBOT
brazen gorge
#

how many kilometers

heavy chasm
#

uhh

brazen gorge
#

first he was 510 km away

#

now he is 105 km away

heavy chasm
#

he drove

#

405 km

brazen gorge
#

yep

#

how many hours is from 8 am to 1 pm?

heavy chasm
#

5

brazen gorge
#

yep

#

so in 5 hours, he drove 405 km

heavy chasm
#

yes

brazen gorge
#

do you know the speed formula?

heavy chasm
#

distance over time?

brazen gorge
#

yes

heavy chasm
#

ok

brazen gorge
#

you have distance, you have time. result will be your answer

heavy chasm
#

81

brazen gorge
#

yep

#

that's it

heavy chasm
#

can u help with another one

brazen gorge
#

yes

heavy chasm
brazen gorge
#

okay

#

how many marbles in total are there?

heavy chasm
#

24

brazen gorge
#

oh it says 24

#

lol

heavy chasm
#

yea

brazen gorge
#

what's the formula for probability?

#

or like calculate the probability of drawing a red marble

heavy chasm
#

uhh

brazen gorge
heavy chasm
#

8/24

brazen gorge
#

yes

#

let n be the number you need to add

#

so you get $\frac{8+n}{24+n}=\frac{3}{5}$

warm shaleBOT
#

artemetra

brazen gorge
#

solve for n from here

#

hint: cross-multiply

heavy chasm
#

multiply 8+n times 5?

brazen gorge
#

uh

#

that will be the lhs

#

so yeah

heavy chasm
#

what's lhs

brazen gorge
#

left hand side

heavy chasm
#

72n/40n?

brazen gorge
heavy chasm
#

or does the n like

#

stay away

brazen gorge
#

you should do $5(8+n)=3(24+n)$

warm shaleBOT
#

artemetra

brazen gorge
#

that's what i meant by cross-multiply

heavy chasm
#

ight lemme solve

#

wait how does 5 end up on the left side

#

oh nvm

#

u got rid of both denominators

brazen gorge
heavy chasm
#

40+n=72+n

#

oh wait

brazen gorge
#

no

heavy chasm
#

ignore that

#

5n+40=3n+72

brazen gorge
#

yes

#

do you know how to proceed from there?

heavy chasm
#

lemme think

#

subtract 40 to put on right side then divide 3m

#

3n*

#

5n/3n=32

#

i thibk i messed up

#

wait

#

5n=96n

#

n=96n/5

brazen gorge
#

no

heavy chasm
#

dammit

brazen gorge
heavy chasm
#

ohhh

#

u right

#

n=16

#

that was easier

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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tawdry talon
#

If we let $\xi$ be random variable which denotes amount of points on the dice, then $E\xi^2=1^2P(1)+2^2P(4)$?

warm shaleBOT
#

kitten

timid silo
#

is that the q? because that doesnt seem correct. what about the other options:2,3,5,6?

tawdry talon
#

Isn't P(3^2) = 0 and on because we have 6-sides dice? sadcat

timid silo
#

No. We aren't squaring \zeta inside the probability.

#

$$E[\zeta^2] = 1^2 P(1) + 2^2 P(2) + 3^2 P(3) + 4^2 P(4)+5^2 P(5) + 6^2 P(6)$$

warm shaleBOT
#

swimmingland

tawdry talon
#

Ohhh, I see, thank you 😊

#

.close

obtuse pebbleBOT
#
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timid silo
#

Sure thing! 🙂

obtuse pebbleBOT
#
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dark idol
obtuse pebbleBOT
dark idol
#

U can move around any of these boxes

obtuse pebbleBOT
#

@dark idol Has your question been resolved?

dark idol
#

<@&286206848099549185>

#

<@&286206848099549185>

wide sequoia
#

Hey

soft grove
#

What

wide sequoia
#

how can i help

dark idol
wide sequoia
soft grove
#

What is 2+1

#

Helpers pls help

wide sequoia
#

IDK

soft grove
#

NOOOO

wide sequoia
#

BrO ThAT tO HArD

soft grove
#

It's the hardest question in the world

wide sequoia
#

WAIR

#

ITS 3

#

IT MUST BE 3

soft grove
#

YEAH UR RIGHT

wide sequoia
#

OMG

#

IM ALBERY ENSITE

soft grove
#

WE ARE GENUISES

wide sequoia
#

IK

dark idol
#

Ok so u guys don’t know it either

wide sequoia
#

Let me check

#

Its ask the teacher for extra credit

#

lol

#

@dark idol

#

What grade are you

dark idol
wide sequoia
#

Joke anwser

dark idol
#

Ok so how I do it

wide sequoia
#

What grade are you, and what math class is this

dark idol
#

It’s calculus college

wide sequoia
#

Okay

#

Yeah

#

This is above my level

dark idol
#

Bruh

wide sequoia
#

Im only grade 11

dark idol
#

No problem

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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sand forum
#

I don't understand the solution. Why are they using inclusion exclusion for 4-sets, but getting so few terms? There should be 15 terms to work out

drifting wraith
#

they have 14 terms

#

4, then 6, then 4

#

they are missing the last one

sand forum
#

so, there is a problem with the solution?

#

I see they have grouped them now, and that there is 4 + 4 choose 2 + 4 choose 3 = 14 terms ...

drifting wraith
#

i'm not sure, i would say yes

sand forum
#

is there another approach than inclusion exclusion to this problem

drifting wraith
#

oh i see

#

the last term is 0

#

7 cards can't fit 4 pairs

sand forum
#

oh yea, there is only 7 cards

#

I missed that some how

drifting wraith
sand forum
#

?

drifting wraith
#

hm

#

no nvm

sand forum
#

probability of an ace and king of the same suit in a 7 card draw from 52 standard card deck

#

can we just compute a conditional probability maybe

#

hmm no maybe that is harder

#

maybe I have a skill issue since I didnt try to group the terms like the solution did which made the work more expensive for me

obtuse pebbleBOT
#

@sand forum Has your question been resolved?

#
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#
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long hedge
#

$81\int :sec^5\theta -sec^3\theta :d\theta$

obtuse pebbleBOT
warm shaleBOT
#

putridplanet

long hedge
#

i know this is a dumb question but you can't just subtract the sec^3 from sec^5 like that to get sec^2 because you are taking the integral of both

#

that would only work if there was no integral

#

right ?

#

ok but that would just make the answer tan +c

#

and my teacher didn't do it that way she took the individual integral of both

#

oh i thought you said you could

#

ok

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
#
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faint cape
#
  1. Question: Complete the table so that sine theta is expressed in terms of the functions given across the top. (Cot theta)
faint cape
#

my work so far

#

I am so confused on what this even wants me to do

#

I know to use trig identities but like idek what to do other that 1/cos

#

these are my options

#

more of what i tried

#

im actually working on the sec one first my bad

#

<@&286206848099549185>

#

do i ping at 15 min intervals?

#

<@&286206848099549185>

obtuse pebbleBOT
#

@faint cape Has your question been resolved?

obtuse pebbleBOT
#

@faint cape Has your question been resolved?

obtuse pebbleBOT
#
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#
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tawdry saddle
#

im wondering if i can cancel out the (x + 3) in the numerator and denominator. Usually it would be obvious but there is a coefficiant of 2 in the denominator and i dont know if that matters or not. Can anyone let me know if its still ok to cancel out the (x + 3)?

latent walrus
#

depends what youre doing

#

but the 2 isnt an issue to whether you can cancel

tawdry saddle
#

ok

#

Im simplifying a fraction

latent walrus
#

i suppose you can then

tawdry saddle
#

This is the full question

timid silo
#

you can cancel them

tawdry saddle
#

ok

latent walrus
#

if youre doing graph stuff, just keep in mind that if x is -3 you have a hole and its undefined there

tawdry saddle
latent walrus
#

since its a removable discontinuity

tawdry saddle
#

yeah Im very confused on the hole thing

latent walrus
#

a hole happens when the function is undefined at a point but its limit has a value there

tawdry saddle
#

if it cancels out its a hole?

latent walrus
#

in a limit the x-3 will cancel

#

so the limit is defined at -3, but the function isnt

#

hence a hole

#

thats why i meant be careful in cancelling

#

context is important

tawdry saddle
#

now when i find the verticle asymptotes

#

do i keep the x + 3

#

or would it only be 1 asymptote then

#

Right now this is all I have

latent walrus
#

would just be the x-3
we know that (x+3) gives us a hole rather than an asymptote, so just the x-2

#

you want the limit to be undefined

#

the x+3 disappears in limits

tawdry saddle
#

so what do i put for holes

latent walrus
#

function undefined and limit defined

tawdry saddle
#

Do I just write the x + 3?

latent walrus
#

see where the function is undefined, check if the limit is or not

tawdry saddle
#

I remember my teacher showed us some equation but I don’t remember it

latent walrus
#

if it is then its a hole, if its not then its an asymptote

tawdry saddle
#

so if im cancelling out x + 3

#

is the hole x - 3 or x + 3

#

i mean x = 3

#

or x = -3

#

thats how my teacher wants us to write it

latent walrus
#

see where the function is undefined:+3 and -3
look at the limits, x+3 cancels out, and so the limit at -3 is defined, this must then be a hole
look at +3, the limit is also undefined since x-3 doesnt cancel, this is an asymptote

#

hole: f undefined, lim defined
asymp: f undefined, lim undefined

tawdry saddle
#

when i put the equation in my calculator both -3 and 3 are undefined

#

does that mean they are both holes?

latent walrus
#

... no, what are you talking about

#

have you read what ive actually said?

tawdry saddle
#

Im trying but i have no idea what it means

#

my teacher didnt teach us like this

latent walrus
#

yes f is undefined at +3 and -3, but the limits arent necessarily

tawdry saddle
#

ok

#

my teacher never told us what a limit is

#

or at least she must havbe explained it differently

#

So i dont reallyt know what you mean when you are talking about limits

latent walrus
#

oh, you dont know limits

#

okay, if the part that makes the function undefined at a point can cancel out, then that is a hole, if it cant then its an asymptote

tawdry saddle
#

okay so x+3 is a hole then right?

#

because i canceled it out

latent walrus
#

-3 is a hole yes

tawdry saddle
#

yes x = -3

#

thats what i wanted to know

#

if (X + 3) chances to x = -3

#

changes*

latent walrus
#

you lost me there

tawdry saddle
#

i canceled out the (x + 3)

latent walrus
#

x+3 doesnt change to x=-3

tawdry saddle
#

but i canceled the x + 3 and you said x -3 is a hole

latent walrus
#

you need to stop writing things like this, its confusing

#

x=-3 is a hole yes because solving (x+3)=0 gives x=-3 and the (x+3) cancels in the function

#

you lost me at the word 'changes' because it makes no sense

tawdry saddle
#

ok sorry

latent walrus
#

if you mean x=-3 then write that, if youre referring to the x-3 in the function then write x-3

#

there has to be distinction

tawdry saddle
#

this is how my teacher taught us to solve holes

latent walrus
#

um, what was the original function

tawdry saddle
latent walrus
#

okay, that makes sense, i very much dont like how its written though

#

that last part is not f(x)

#

its a different function

#

but yeah, theres a hole at 0, because the function is undefined but the part making it so can cancel

tawdry saddle
#

here is my work and the original function

#

sorry its on its side

latent walrus
#

it would be fine if using limits but this isnt being done

#

the point (0,2) is not even part of f

#

sure theres a hole at 0 but saying f=-2 there?? Why are they doing that

tawdry saddle
#

Dude I have no idea this is for a grade though honestly I just want to get a good grade

#

I barely even understand the mechanics of this

latent walrus
#

the limit at 0 is 2, not f itself

#

f is undefined at 0

#

teacher cutting corners

tawdry saddle
#

ok

#

i dont really understand

latent walrus
#

its fine to say the hole is at that point you found, but dont say that its the value of f there

tawdry saddle
#

so what do i put

latent walrus
#

its a notation issue, it doesnt make sense without using limits
you can say the hole is located at (-3,-16/(-12)) ie (-3,4/3)

#

just dont say f(-3)=4/3
if you want to be classy, say
$$\lim_{x\to{-3}} f(x) =\lim_{x\to{-3}} \frac{3x-4}{2(x-3)}= \frac{4}{3}$$

warm shaleBOT
#

AℤØ

latent walrus
#

that would be the most correct

tawdry saddle
#

Is there supposed to be 2 separate or did I graph it wrong

latent walrus
#

though i get that may be beyond your course

#

you cant see a hole on a graph

tawdry saddle
tawdry saddle
latent walrus
#

yeah of course

#

where there is a hole we often draw a hollow circle at that point

tawdry saddle
#

Ok

#

I’m confused on how to graph this

#

Like on paper

#

I need to use that x and y chart

#

And idk which values to pick

latent walrus
#

but id label your axes first

#

might help in choosing

tawdry saddle
#

3 is also an error

#

What is that about

latent walrus
#

3 is the asymptote

tawdry saddle
#

Ok does that matter when I graph

latent walrus
#

yeah, you have to draw it

#

check which way its going from each side

latent walrus
tawdry saddle
#

Are these values ok

latent walrus
#

instead of error, write undefined

#

put those can work

#

you dont have space on your graph to get to 5 though

tawdry saddle
#

What do you mean

#

I have plenty of space

latent walrus
#

you really want some closer points the the undefined bits to see the behavior there

latent walrus
tawdry saddle
latent walrus
#

you havent labeled your axes with any numbers

#

no one can tell the scale

#

but its definitely wrong anyway, your asymptote isnt vertical

#

thats important, itll help to actually mark where x=3 accurately is

tawdry saddle
#

Well idk how to fix it I checked every step

#

It’s getting late where I am

#

Honestly I’m trying to finish this

latent walrus
#

you need to label your axes, i told you

#

you cant make an accurate graph if you dont know where your values are

tawdry saddle
#

Oh the bottom one can’t pass the 3

#

Because that’s the asymptote

latent walrus
#

the function cant cross the line x=3 at any point

tawdry saddle
#

Got it

#

I fixed and laboed

#

Ok next question

latent walrus
tawdry saddle
#

i was very confused when the teacher explained this

latent walrus
#

i presume youve seen the rational root theorem if this came up

tawdry saddle
#

probably

#

i honestly had no idea what was going on during this

#

i know the rest pretty well but this possible rational roots thing

#

i dont get it

latent walrus
#

this is an overview and example

#

actually ignore that its wrong oops

#

this one is fine

tawdry saddle
#

so you divide the factors of the first coefficient with the factors of the last one?

#

and thats all the possible ones

latent walrus
#

factors of the constant by the factors of the coefficient of highest order x yeah

#

part b will probably involve some polynomial division of some form

tawdry saddle
#

so what do i do with all those possible ones

#

i think i remember my teacher talking about substituting but i may be wrong

latent walrus
#

you sub them all into the polynomial to see which ones are actually roots

tawdry saddle
#

how do i know if its a root

#

if it equals 0?

latent walrus
#

yeah

tawdry saddle
#

damn i gotta substitute all of those

latent walrus
#

heh

tawdry saddle
#

do i need to do the +- seperately

latent walrus
#

yup

latent walrus
#

oh well, at least its relevant

tawdry saddle
#

for my roots

#

i got 1, -1/2, 1/3, 3

#

well at least its 4 roots

#

no idea if its right or not

#

next question

#

😭

latent walrus
#

looks worse than it is, just factorise everything you possibly can

tawdry saddle
#

first i need to swap the numerator and denomerator of the 2nd part right

#

and change it to multiply

latent walrus
#

sure

tawdry saddle
#

problem is so long even photomath couldnt recognize it

#

i know how to do this its just going to take me so long and i want to go sleep

#

im just going to skip for now

#

@latent walrus isnt this just horizontal asymptote?

#

or is there something more

#

Here’s my work

obtuse pebbleBOT
#

@tawdry saddle Has your question been resolved?

#
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gritty grotto
#

i dont where to go after i put it into the matrix format

gritty grotto
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ik im supposed to get 3 0s and lke check but like what is the question asking

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im just confused in general

mystic dagger
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you must determine range of k

gritty grotto
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so will it be like k>n?

mystic dagger
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i think maybe

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you can get a, b, c by k using taken assumptions

gritty grotto
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where do i go from here

mystic dagger
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solve them using [-4, 2, 2k]

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do you solve

gritty grotto
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wdym

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oh

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using the answers

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how do i solve

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i dont get

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how do get rid of the k^2

mystic dagger
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A[a; b; c] = [-4, 2, 2k]

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[a;b;c] = A^(-1)*[-4, 2, 2k]

gritty grotto
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wait hold up

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how d u get abc

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and what are you using

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im not too sure

mystic dagger
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using formula

gritty grotto
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which?

mystic dagger
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Matrix

gritty grotto
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?? trheres formual

mystic dagger
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are you university student?

gritty grotto
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no

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i am

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in year 12

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15 years old

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what does it have to do?

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with that

mystic dagger
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oh, it is formula which can learn in university

gritty grotto
mystic dagger
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i will think some other ways

gritty grotto
gritty grotto
mystic dagger
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oh, i think it is not difficult problem.

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this problem is which type in your textbook

gritty grotto
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i thnk we use gausean

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method

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gaussian

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elimination

mystic dagger
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oh

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so this problem means that get appropriate k to not exist proper a, b, c

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right?

gritty grotto
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i think

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im lost

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i learnt system of eqn today

mystic dagger
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i think determinant value of matrix should be 0

gritty grotto
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what is determinant

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idek at this point

mystic dagger
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oh, no

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this is also unversity's

gritty grotto
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ok... so this is

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the system

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of eqn

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what should i do with it?

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substitute kc?

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solve for kc?

mystic dagger
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substitute

gritty grotto
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ok

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but then what?

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use discriminant?

mystic dagger
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and also substitue ak^2

gritty grotto
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and then sub it into q1 or 2

mystic dagger
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use eq1, eq2 bk = 3

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right?

gritty grotto
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yup

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hi?

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<@&286206848099549185>

fierce elbow
mystic dagger
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k must be -2 or 2

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what is correct answer?

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@gritty grotto

gritty grotto
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yes

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thats correct

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but how do u do it

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@mystic dagger

mystic dagger
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-2 and 2 is all ok?

gritty grotto
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yup thats right

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but how do i get the answer

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without using uni stuff

mystic dagger
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what is uni stuff?

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i think there might be more solutions, i guess 4 solutions, but it is too difficult to calculate them

gritty grotto
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is there a way to do it just through pure substitution

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basics?

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what did u use?

mystic dagger
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you only use gaussian elimination

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and finally you can get:

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k^3-4k | 2k^3- 6k+4

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so solution will be +2 or -2

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got it?

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hey @gritty grotto

gritty grotto
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do u have working i can follow?

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sorry im not that good at visualising it

gritty grotto
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|

mystic dagger
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gaussian elimination

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wait a minute

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i will send answer

gritty grotto
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okk

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i learnt this method today

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im not even sure myself

mystic dagger
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first is your image

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ok?

gritty grotto
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yuh

mystic dagger
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second is

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ok?

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simply substitute eq1 from eq2

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hi?

gritty grotto
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wait

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im tryna understand

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oh is

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oh ic

mystic dagger
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third you multiply 4/k^2 to eq1 and substitude from eq3

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let 4 goes 0

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ok?

gritty grotto
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wait lemme try

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wdym by substitute from eq 3

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so eq3-eq1?

mystic dagger
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eq1 remains unchanged

gritty grotto
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yeah i just write it out

mystic dagger
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you must do eq3 - eq1*(4/k^2)

gritty grotto
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yup

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ok

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like th

mystic dagger
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yeah

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and like this eq2. and eq.3

gritty grotto
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wdym?

mystic dagger
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eq3's second term goes 0

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ok?

gritty grotto
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eq2-eq3?

mystic dagger
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... ... ...
0 ... ...
0 0 ...

gritty grotto
#

eq3-eq2?

gritty grotto
mystic dagger
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eq3 - eq2*(2+4/k)/2k

gritty grotto
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wait