#help-0

1 messages · Page 779 of 1

vestal hollow
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Sorry Chai T. Rex, still trying to write it in terms of the problem

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Like with the values given

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And trying to abstract it so instead of 2500 it's just "d" as a distance

oak chasm
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Right, you can replace 2500 with d for the distance between Frisco and Kansas City.

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You don't need any other values.

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Well, I guess you can use the times.

vestal hollow
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Let the distance from Frisco and Kansas City be d. Let f(t) be the distance traveled from Frisco to Kansas City on the first trip and g(t) the distance traveled from Frisco to Kansas City on the second trip, where t represents time.

f(8:00 AM) = 0 and f(5:00 PM) = d.
g(8:00 AM) = d and g(5:00 PM) = 0.

Then, f(8:00 AM) - g(8:00 AM) = -d and f(5:00 PM) - g(5:00 PM) = d.

0 is between -d and d

So by the IVT, f(t) - g(t) must equal 0 at some t in = [-t, t]

Then at some point the busses cross (the distance between them becomes zero) at some time t.

I feel like I messed this up a bit thonk

oak chasm
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t from 8 to 17

f(t) - g(t) is continuous

f(8) - g(8) = -d
f(17) - g(17) = d

0 is between -d and d

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Oh, you're fine.

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The only thing is t ∈ [8 AM, 5 PM]

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Since t isn't a distance.

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You'll want to define f(t) and g(t) better.

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They're both the distance to Frisco at time t.

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f(t) is the distance to Frisco at time t on the first trip.

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g(t) is the distance to Frisco at time t on the second trip.

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Sorry, from Frisco, not to Frisco.

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The distance is between two points, so the distance from Frisco to Kansas City, if those are the two points, is constant, so you don't want to use that definition.

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If it's the distance from the bus to Frisco, that isn't constant.

vestal hollow
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The only place I am getting hitched up is physically interpreting f(8:00 AM) - g(8:00 AM) = -d

oak chasm
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Well, what's f(8 AM)?

vestal hollow
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The distance from Frisco at 8 AM on the first trip. So 0.

oak chasm
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What's g(8 AM)?

vestal hollow
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The distance from Frisco at 8 AM on the second trip. So d

oak chasm
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What's f(8 AM) - g(8 AM)?

vestal hollow
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Well yeah, 0 - d = -d. But what does that mean physically? 😅

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It's a negative distance so I guess it's meaningless physically

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Only a quantity that exists within the mathematics necessary to get a solution

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But I can';t help but feel like there should be a way to visualize it

oak chasm
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It's how much closer the second bus is to Frisco than the first bus.

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The second bus starts out as -d closer than the first bus.

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Or d farther.

vestal hollow
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Wow thank you so much

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I think I'll have to rewrite it once or twice more but this makes a lot more sense

oak chasm
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You're welcome.

harsh belfry
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So I have the correct answer

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however, apparently theres an issue.

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I ended up messaging my professor

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and this is what he said

oak chasm
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Right, you took the limit.

harsh belfry
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so essentially would my answer end up being

oak chasm
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What's f(x + Δx)?

harsh belfry
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would my answer here end up being
H^2+3x^2+3xh

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?

harsh belfry
harsh belfry
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Thanks, wanted to make sure since I only have one attempt left.

oak chasm
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Make sure to use Δx.

harsh belfry
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oops!

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everything check out?

oak chasm
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I'd put (Δx)² just in case.

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But other than that, it looks good.

harsh belfry
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I really hope this works out... I hate the awkward notation for change in x

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would be nice if it was represented by h or just delta

shrewd prism
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9x^2+x^2=15^2
why am I not allowed to sqr root both sides of the equation and end up with
9x+x=15
i am dying

harsh belfry
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got it right, thanks chai

oak chasm
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You're welcome.

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@shrewd prism Powers and roots don't distribute over addition.

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First combine like terms.

shrewd prism
oak chasm
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Yes.

shrewd prism
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oo ok

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ty

oak chasm
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You're welcome.

shrewd prism
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10x^2=15^2
x^2=1.5^2
x=1.5
this is wrong right? ^
10x^2=15^2
x^2=(15^2)/10
x^2=22.5
x=sqrroot(22.5)

oak chasm
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Yes, it's incorrect. The second one is correct.

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But there's a catch.

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x² = 22.5 has two solutions.

shrewd prism
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ohhh right the + and - thing right

oak chasm
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Right.

shrewd prism
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ok ty

oak chasm
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The square root of x² is |x|

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|x| = sqrt(22.5), so x = ±sqrt(22.5).

shrewd prism
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ok tysm

oak chasm
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No problem.

shrewd prism
oak chasm
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Right.

shrewd prism
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so if I had 3x^2 * x^2 =...
could I square root it into this?
sqrroot(3)x*x

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wait no I need to square root the 3

oak chasm
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Yes, if you do the square root on the 3.

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Powers and roots distribute over multiplication and division.

shrewd prism
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hmm ok tysm for all ur help

oak chasm
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You're welcome.

shrewd prism
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I didn't know about this until now ;-;

harsh belfry
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Sorry to bother you Chai, but I assume this problem is incorrect due to a similar issue. But I'm not given a deltax to work with which is confusing me.

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What would I do here?

oak chasm
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What's f(x)?

shrewd prism
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o right so if I had 3x^2 +y^2 = ...
can I still sqrroot the whole equation?

oak chasm
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What does and mean?

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Addition? Multiplication?

shrewd prism
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I meant + oops

oak chasm
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Oh, OK.

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You could, but you can't distribute.

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sqrt(3x² + y²)

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Square root of the whole thing.

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Not sqrt(3x²) + sqrt(y²).

shrewd prism
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right so sqrt(3)x+y?

oak chasm
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No.

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You can't distribute a root over addition.

shrewd prism
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huh what's the difference

oak chasm
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The difference between what?

shrewd prism
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oh wait

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nvm

harsh belfry
oak chasm
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@harsh belfry What's f(3)?

harsh belfry
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(3)

oak chasm
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No.

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f(x) = x³ - 9x, right?

harsh belfry
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Yessir

oak chasm
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f(3) = (3)³ - 9(3)

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You replace the x with (3).

harsh belfry
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Would it not be written like this?

oak chasm
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No.

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What's f(3)?

harsh belfry
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Ah I think I see

oak chasm
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Not quite.

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f(x) = x³ - 9x

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There's two xs to replace.

shrewd prism
oak chasm
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@shrewd prism If they're multiplied or divided.

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Powers and roots distribute over multiplication and division.

harsh belfry
oak chasm
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No.

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Replace x with (3).

harsh belfry
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Im confused

shrewd prism
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right

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ty

oak chasm
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You're welcome.

harsh belfry
oak chasm
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Right.

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What's that?

harsh belfry
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Ahhhhh I didnt know that was possible

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it should equal zero I think

oak chasm
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Right.

harsh belfry
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Let me check

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ah ok

oak chasm
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What's f(x) - f(3)?

harsh belfry
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x^3-9x

ocean sealBOT
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Chai T. Rex

\[\frac{x^3 - 9x}{x - 3}\]
oak chasm
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Factor the top.

harsh belfry
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If I factor the numerator it should be x^2+3x

oak chasm
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Wait.

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Oh, OK, let's see.

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No.

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What's the common factor of x³ and 9x?

harsh belfry
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x?

ocean sealBOT
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Chai T. Rex

harsh belfry
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ahhhh

oak chasm
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Then you factor x² - 9.

harsh belfry
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then cancel the x's

oak chasm
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No, you can only cancel whole factors.

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There's no factor of x on the bottom.

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There's a factor of x - 3, but that's not x.

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So factor x² - 9 on top.

harsh belfry
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ah I misunderstood the purpose of the setup then maybe

gray kiln
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no

oak chasm
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Right, you can't do that because x - 3 is a whole factor.

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x isn't on the bottom as a factor.

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You can only cancel factors.

gray kiln
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treat x-3 a whole

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thing

oak chasm
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Factors are things you multiply, not add or subtract.

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On the bottom, the only factor you have is x - 3, not x.

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x isn't multiplied by something on the bottom, so x isn't a factor.

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Does that make sense?

harsh belfry
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I see

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I never knew that

oak chasm
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x is multiplied by something on top.

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It's a factor there, but not the bottom.

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So factor x² - 9.

gray kiln
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at fisrt, when i was learning i did the same thing😆

harsh belfry
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x(x+3)(x+3)

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right?

oak chasm
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Almost.

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(x + 3)(x + 3) isn't x² - 9.

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How do you factor a difference of squares?

harsh belfry
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wouldnt we just end up with the same answer when simplifying that?

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x^3-9x?

oak chasm
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No.

harsh belfry
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am I doing something wrong

oak chasm
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Yes.

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How do you factor x² - 9?

harsh belfry
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I'm so confused now

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I don't know

gray kiln
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@harsh belfry do u know to find zero of polynomial?

oak chasm
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With a difference of squares, you have something squared minus something squared.

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It's a difference of two squares.

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Does that make sense?

alpine sable
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You can’t factor out if there is a plus/minus sign @harsh belfry

harsh belfry
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I really really don't understand anything right now.

shrewd prism
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isn't there something about (a+b)(a-b) right

harsh belfry
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I don't know what to say

shrewd prism
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about quadratics or something

gray kiln
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1 method is that u could try to find the values of x for which x^2-9 is 0

oak chasm
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OK, so x² is a square, right?

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Does that make sense?

harsh belfry
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yeah

oak chasm
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9 is a square right?

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It's 3².

harsh belfry
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yes

shrewd prism
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omigosh right ok

oak chasm
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x² - 3² is a difference of squares.

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It's the difference (subtraction) of two squares.

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Does that make sense?

shrewd prism
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(x+3)(x-3)?

harsh belfry
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ok

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so now Im somewhat following

oak chasm
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a² - b² = (a + b)(a - b)

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That's how you factor a difference of squares.

harsh belfry
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yes

shrewd prism
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waw ok ty

oak chasm
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So, we have x² - 3².

harsh belfry
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yes

oak chasm
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x² - 3² = (x + 3)(x - 3).

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Does that make sense?

harsh belfry
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I'll have to look into it more on my own to make sure I understand this

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but I get the premise

oak chasm
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OK, let's practice once.

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5² - 3²

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What does that factor to?

harsh belfry
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16?

oak chasm
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No, factor it.

harsh belfry
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(5)(5) - (3)(3)

oak chasm
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No.

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Factor it.

alpine sable
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@harsh belfry different language, but look at the bottom one

oak chasm
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Do you remember how I showed you to factor a difference of squares?

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a² - b² = (a + b)(a - b)

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We have 5² - 3².

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How do you factor that?

harsh belfry
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(5+3)(5-3) if I'm following the format

oak chasm
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Right.

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(5 + 3)(5 -3)

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8 · 2

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16

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See how you get the right answer this way, too?

harsh belfry
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I do

oak chasm
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OK, so x² - 9 = (x + 3)(x - 3).

ocean sealBOT
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Chai T. Rex

oak chasm
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Now we have three factors on top.

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We have one factor on bottom.

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Can we cancel one of the factors on top with the one on bottom?

harsh belfry
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would x-3 on the top and bottom cancel out

oak chasm
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Yes.

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They're the same factor.

harsh belfry
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x^2+3x would be our answer

oak chasm
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Right.

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So, that's the basics of how to do it.

harsh belfry
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I never would have been able to do this holy shit

gray kiln
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u will be

oak chasm
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Well, if you practice on some more problems with maybe some help when you get stuck, you'll be able to do it.

thorn kindle
alpine sable
silver current
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Can somebody check please

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The solutions shows answer as 6, mine is coming 9

lusty pewter
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The length of a rectangular magazine is 8 cm more than its width and the area of the magazine is
240 cm2. Find the dimensions of the magazine.

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How is this question quadratic?

split oriole
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Like what is e^ln(2)?

silver current
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umm

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what are you trying to suggest?

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i'm unable to comprehend

jagged imp
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you wrote $5^{\ln_5(2)}=5$. this is incorrect

ocean sealBOT
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Sneaky

silver current
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oh right

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it should be 2

jagged imp
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yes

silver current
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thank you

alpine sable
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hello is this used?

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if not ples help me

split oriole
alpine sable
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no because i dont know what to do

split oriole
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Okk do you have any idea about derivative?

alpine sable
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i ever study it but i forgot

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how can i find the derivative?

split oriole
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Take the derivative of given equation then find dy/dx , at value (7,1) find the values of dy/dx ( that will be slope of tnagent) now use point slope form find equation of that tangent ,same for (-1,5) ,

When you get two tangents just find the point of intersection by elimination,or other mehtod you line

alpine sable
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is finding derivative the only way to solve this?

split oriole
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I know this method ,but wait for someone ,they will help

alpine sable
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bcz my teacher teaching circle without derivative

fervent anchor
split oriole
oak chasm
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You can get the angle to the point.

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From the center of the circle.

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Then the tangent of the angle is the slope to from the center to that point.

alpine sable
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center (2,1)?

oak chasm
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And then the tangent line is perpendicular to the radius line.

fervent anchor
oak chasm
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So, the slope you got for the radius line, you take the negative reciprocal of it.

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@alpine sable Yes.

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So, let's find the radius slope from center (2, 1) to point (7, 11).

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Rise is 10, run is 5.

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Slope is 2.

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Tangent line is perpendicular to radius line.

alpine sable
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what is rise and run

oak chasm
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Do you know how to find a slope?

alpine sable
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no

oak chasm
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Do you know how to find a gradient?

alpine sable
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no also

oak chasm
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OK, so the slope is how far it goes up over how far it goes right.

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The rise over the run.

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So, from (2, 1) to (7, 11), it goes up 10.

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It goes right 5.

alpine sable
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ohh

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yes

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how to find slope

oak chasm
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10/5

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2

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Does that make sense?

alpine sable
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yes

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then what to do?

oak chasm
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OK, so that's the radius line slope.

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The slope of the radius from the center to that point.

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Now a tangent line is perpendicular to a radius line.

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A perpendicular slope is the negative reciprocal.

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2

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-2

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-1/2

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See how I took the negative, then the reciprocal?

alpine sable
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im confused

oak chasm
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@alpine sable Where are you stuck?

alpine sable
#

all

fervent anchor
dense blaze
#

can i check that the limit for 1/x^2 as x tends to 0 doesnt exist? or is it + infinity

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even though the both the left and right side tends to (same value) infinity

raven swallow
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When do we say that the limit exists?

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Go look up "when the limit exists" real quick

gray isle
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the limit can be represented as +inf but technically the limit doesn't exist as +inf isn't a number

split oriole
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I think we can if we work on extended real line.

dense blaze
raven swallow
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Example when it doesn't: 1/x

dense blaze
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but.i think ramonov said it isnt a number

raven swallow
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as far as I'm concerned

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Infty is not a number, of course, but at least it's the same for right- and left-sided limit

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We say DNE for cases like 1/x, x to 0, and +INF for cases like 1/x^2, x to 0

thin berry
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Can anyone help what is the idea for it

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Like what should i do to know

split oriole
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For infinite solution a1/a2=1/b2=c1/c2

thin berry
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a1/a2 is 1z/6z ? Orr

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Same idea with b and c then

dull oak
#

the answer is

thin berry
split oriole
dull oak
split oriole
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That is variable

dull oak
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so the answer is 4<distance<5

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but why

thin berry
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Thank you so much

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Hmm so it is a no solution right ? @split oriole

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Oooh got it

narrow carbon
#

anyone knows what I'm supposed to do here? I kind of don't get it

raven swallow
#

Is this a test?

narrow carbon
#

nopee, my test is next week

raven swallow
#

Well the first problem, what does P stand for?

narrow carbon
#

that's what I don't know. They were written like that without any further explanation

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I don't even know where the numbers came from

raven swallow
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Wdym you don't know

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The problem says

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P for Population

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V for Vendetta

narrow carbon
#

huh

raven swallow
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P is population

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t is time in years, since time is the only thing that the population depends on

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In this problem

narrow carbon
#

how about the numbers?

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60,1 and 6

raven swallow
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It doesn't matter, they ask you to find years, years is time "t"

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You wanna find such t that P =....

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That P=48

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Which leads to the equation

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P(t)=48
Solve for t
Get years needed

raven swallow
narrow carbon
#

ayt ayt thank youu so much

rough python
#

I have figured upto that number of sylow 2-subgroups will be 1 or 3 and the number of sylow 3-subgroups will be 1 or 4. But I don't know how to determine the exact number of those two sylow p-subgroups.

vale wigeon
#

well

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for p=2 why not look for a subgroup of order 8?

split oriole
#

Now use this fact

round hawk
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can someone help me with problem please

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I haven’t figured out which test to use

placid zinc
#

For any general series tests
First question to ask yourself:
"Is it alternating?"

Second question:
"Is the limit to 0?"

Third question:
"Can I integrate it?"

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It isn't alternating.
Limit is obv 0.
It looks integrable

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Integral test is a winner here

strange fossil
#

<@&286206848099549185>

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Part 2 and 3

round hawk
#

@placid zinc That’s a very useful suggestion. Got it! Thanks~

strange fossil
dense carbon
#

if I have how does it go from that to that

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√3 + 2√3 - 4 / √3 + 2√3 + 4

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3√3 - 4/3√3 + 4

rough python
fresh bolt
dense carbon
fresh bolt
#

how does this √3 + 2√3 - 4 / √3 + 2√3 + 4 become 3√3 - 4/3√3 + 4?

dense carbon
#

yes

fresh bolt
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okay

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do you know how to simplify √3 + 2√3 - 4 ?

dense carbon
#

(x+a) (x+b) formula?

fresh bolt
#

no

dense carbon
#

no :/

fresh bolt
#

√3 is simply equivalent to 1 * √3 which is 1√3

dense carbon
#

ohh

fresh bolt
#

1 * any value will return the value itself right? eg. 1 * 10 = 10, 1 * 100 = 100 etc.

dense carbon
#

okay but then

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there are 2 root3

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how do they become only 1?

fresh bolt
#

yea so √3 + 2√3 - 4 is basically = 1√3 + 2√3 - 4 = 3√3 - 4

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of course you dont have to show the 1√3 part if you know how it works

dense carbon
#

oh ok

fresh bolt
dense carbon
#

i meant

fresh bolt
#

after adding 2

dense carbon
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we have 1√3 + 2√3

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so 1+2 = 3

fresh bolt
#

yea

dense carbon
#

but what abou √3 + √3?

fresh bolt
#

√3 + √3 is 2√3

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but now the qn is asking 1√3 + 2√3 so its 3√3

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okay how about this

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you know factorization?

dense carbon
#

oh okay wait

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i got it

fresh bolt
#

1√3 + 2√3 = √3 (1 + 2) = 3√3 * factor out √3

alpine sable
#

Hey there! The path to fail is dead. @dense carbon

rough python
dense blaze
#

how do i use the second statement to get the qn in the first sentence

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i initially tried to change it to sin5x/5x * 5x/sin4x but it doesnt work

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i could use the double angle formula but i think the qn wants us to use the second equation

fringe robin
# dense blaze

divide and mulitply num by 5x and divide and multiply denominator by 4x

dense blaze
#

i get (1)(5/4)

fringe robin
arctic wren
#

If my rate is 20kPa/min do i have to convert to seconds? If so, how? Cause Pa = kg/m.s²

arctic wren
gray isle
#

multiply by 1 for unit conversion. eg multiply by min/(60 sec)

fervent anchor
#

See that what you want?

fervent anchor
#

@arctic wren

arctic wren
#

Tyy

fervent anchor
#

Yea np👍

midnight sapphire
#

im new to the course im doing i know its low level for u guys

#

dont rinse me lmao

vale wigeon
#

have you ever done things with composition of functions before?

midnight sapphire
#

very little

#

learning hahah

chilly tide
#

how does this simplify to n+2/(n+1)! as i am getting the answer of n+2/(n+1)n!

vale wigeon
#

have you plugged numbers into functions before?

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@chilly tide channel busy please move

midnight sapphire
#

yes

chilly tide
midnight sapphire
#

iv plugged into function before

vale wigeon
#

okay, so you know that, for example, f(42069) would be just 10 + 42069

midnight sapphire
#

but not this level

vale wigeon
#

@chilly tide any one that's free right now

vale wigeon
#

okay well f(g(x)) is no different

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f(g(x)) = 10 + g(x)

midnight sapphire
#

oh HAHAHAH

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i though it was alot harder

vale wigeon
#

we all overthink things from time to time

midnight sapphire
#

well thanks hahah

chilly tide
#

ye i kinda figured out indirectly when i substituted n=4

#

i dont understand how you know just by looking at the statement but it is true

rocky atlas
#

Because 5!=5 x 4 x 3 x 2 x 1, which is 5 x 4!

#

if n is 4 you would multiply 5 to 4 factorial that is n +1 to n!

fervent anchor
rocky atlas
#

It's the concept of instant conversion of higher factorial into lower factorial

#

Practise questions to get mastery of this concept!

#

By shortcut method I know answer is 3/2

#

But I want to know if this question of mine when asked in exam, how am I supposed to solve it with proper method which doesn't require me to use binomial expansion

vale wigeon
#

divide numerator and denominator by x^10

stuck jolt
#

^

vale wigeon
#

they're clearly both tenth-degree polynomials, which hopefully is obvious without any expansion

rocky atlas
#

Still infinity by infinity form

vale wigeon
#

???

rocky atlas
#

X to the power 10 will be cut in denominator but what about those binomials..

vale wigeon
#

(x+1)^10/x^10 = ( (x+1)/x )^10 lol

stuck jolt
vale wigeon
#

you will have $\frac{(1 + \frac1x)^{10} + (1 + \frac2x)^{10} + (1 + \frac3x)^{10}}{1 + (1 + \frac3x)^{10}}$

ocean sealBOT
stuck jolt
#

That is clean latex

rocky atlas
#

Oh

#

Power is same so they come within bracket

#

And then it becomes 0

#

Wow it was easy thanks

clear vessel
#

a committee of four is to be selected from 10 candidates, 5 men and 5 women. Assuming each candidate is equally likely to be selected, determine the probabilities that the chosen committee contains: i) no women ii) two men and two women

stuck jolt
#

10C4?

clear vessel
#

no it asks for the probability

#

which I am incredibly confused on

stuck jolt
vale wigeon
#

no it isn't captain_mat01

clear vessel
#

I just dont understand how they get it

stuck jolt
#

Oh wait

#

I am bad

vale wigeon
#

10C4 is the total number of committees possible

clear vessel
#

Ive never seen probability in permutations and combinations question

stuck jolt
#

Probability gets me everytime

vale wigeon
#

qweb, what you have here amounts to choosing a committee at random from the 10C4 possible committees that could be formed

#

so the (favorable outcomes)/(total outcomes) formula can and should be used

clear vessel
#

ooh

#

so I find the number of outcoms for no women (all men) and I divide it by 10C4

vale wigeon
#

yes

#

and likewise for part ii

clear vessel
#

alr thank u so much

icy trail
#

any idea why this dosent work?

#

x=1/9 gives different values for each side of the equation

tropic sail
#

If I wanted to find the speed at any point in time of a car ride. I would take the derivative of a function of distance and time. How would I plot that function of distance and time?? Would I plot the point at each second and connect it like a peicewise function? Or would I use splines to approximate it? How would this be done?

merry iris
icy trail
#

34/3 =/= 40/3

sage bronze
#

,w 7(-1/3) + 9 = 10(-1/3) +10

sage bronze
icy trail
#

hmm okay, thanks for the help !

sage bronze
#

np

alpine sable
#

i got a question on an assignment and i forgot like everything about radical functions over the summer, heres the question

#

60ft/sec = sqrt( 2(?)(32.2ft/sec^2) ) | solve for the (?)

#

im not sure how to handle the 32.3ft/sec^2

#

inside the radical

sage bronze
#

solve for h

alpine sable
#

oh yeah thanks a lot, i forgot like all the simplifying stuff for math

zenith spruce
#

@ebon umbra

#

we're in same server O_O

ebon umbra
#

Oh

slow haven
#

9^(3 + 9^333)

#

what is the last 2 digits of this

#

some nerd got this

#

however I got 29, simply because it seems all powers all 9, 9^x where x is 3 more than a multiple of 9, seem to end in 29

#

I now realise 81 is the correct answer

midnight sapphire
#

10+g(x)

#

1 fuck off

#

2 no

#

i need help with m e math not ur discord nitro shite

slow haven
#

(1 + x)(3 - x) + 12 i think

#

since it's just g of x but with 10 added after

#

you could expand it to make it simpler

humble tinsel
#

just need to make sure of something

#

this equals 0 right

glass lichen
#

Yes

vernal cosmos
#

Yes

glass lichen
#

Since the 0 vector is parallel to all other vectors

#

And just compute the cross lol

humble tinsel
#

thank you

serene linden
#

Hi everyone, I was studying a maths course when I came across this section which detailed Addition and Multiplication on the vector space R2.

#

The first operation, addition, looks like vector addition

#

However, the second, I have never seen before.

#

I was wondering if anyone could help enlighten me.

ionic jewel
#

idk if there's a name but they are just defining an operator

#

their "multiplication" operator does what it says it does

#

it's probably gonna ask to prove that's a vector space or something

serene linden
#

Right,if I am not mistaken, the second one looks like it's asking to multiply 2 vectors . From recent memory, multiplying two vectors are usually either vector or dot product . So when this turned up, I was super confused.

reef urchin
#

it's called a binary operation if it doesn't define what the operator is

ionic jewel
#

it's a newly defined operator, yeah binary operation

#

they are arbitrarily telling you what to do if you see v_1 • v_2

reef urchin
#

what topic is this? looks like advanced algebra

serene linden
#

Undergraduate Maths

#

I think it could be classified under abstract algebra?

#

Has to do with fields and groups. This photo came from a section called complex numbers, specifically where they are building the complex numbers from group and field axioms.

reef urchin
#

ah yes, it's algebra then, and R2 is a set where the elements in your case, are (x1, y1), (x2, y2), and the elements x1,x2,y1,y2 are elements in R. hope this makes sense!

tropic sail
#

how would I calculate the length of the function cosh(x) from a different x points?

#

specificly these 2 marked points

jolly stone
#

so your function will be integral sqrt(1+sinh^2(x)) dx from x=-10 to x=10

#

,w integral sqrt(1+sinh^2(x)) dx

ocean sealBOT
serene linden
#

To the best of my knowledge, R2 is a vector space. It's home to all the coordinates on the normal x and y axis.

#

These coordinates can be treated as vectors.

#

The vectors can be added in this fashion which is similar to the first
statement in the first picture I posted.

#

However, I have never seen two vectors which can be multiplied together give another vector, besides vector product, but those usually use 3D vectors and return 1x3 vectors (3D coordinates).

prisma dove
tropic sail
#

I didn't expect it to be so big...

jolly stone
#

wait i meant sinh(x)

#

i didnt mean to type ^2, soz

#

,w integral sqrt(1+sinh(x)) dx

ocean sealBOT
tropic sail
#

Like this @jolly stone ?

ionic jewel
jolly stone
#

hmm why does it look like that

prisma dove
jolly stone
#

oh it has to be sqrt(1+(f'(x))^2)

prisma dove
# prisma dove

@serene linden that's from John Conway's functions of one complex variable

jolly stone
prisma dove
#

That's one of the many ways to define the field of complex numbers

tropic sail
#

cause it says undefined...

jolly stone
#

,w tanh(10)|cosh(-10)|-tanh(-10)|cosh(-10)|

ocean sealBOT
serene linden
jolly stone
#

oh i see, you have a

prisma dove
#

Yeah so

#

R^2 endowed with this product + vector addition of R^2 makes it a field

#

and in fact

tropic sail
prisma dove
#

if you mean ''specify'' in the sense that this field is now isomorphic to the algebraic closure of R

#

Then yeah

serene linden
#

I have just never seen two R2 coordinates get multiplied to give another coordinate in R2 in this way before so it was kind of confusing

prisma dove
#

yeah so, this multiplication really defines C

prisma dove
#

This comes out intuitively

#

So

#

You already know that the field of complex numbers

#

Is really just adjoing to the real numbers

#

an element called i

#

such that i^2 = -1, right?

#

And with this

#

We can usual algebraic manipulations such that this forms a field

#

Now

#

Let's do the following

serene linden
# prisma dove This comes out intuitively

Sorry to interrupt, but this photo taken from further down the notes, is more familiar to me, especially the multiplication bit. Perhaps this has something to do with the previous photo, just that I can't see the connection?

prisma dove
#

Given $x_{1}+y_{1}i$ and $x_{2} + y_{2}i$ both in $\mathbb{C}$, we know that $(x_{1}+y_{1}i)(x_{2}+y_{2}i) = x_{1}x_{2} + x_{1}y_{2}i + y_{2}x_{1}i + y_{2}y_{1}i^{2} = (x_{1}x_{2}-y_{1}y_{2}) + (x_{1}y_{2}+y_{1}x_{2}) i $
\
\
If we interpret the imaginary part as the second coordinate, we get that
$$(x_{1},x_{2}) \cdot (y_{1}, y_{2}) = (x_{1}x_{2}-y_{1}y_{2}, x_{1}y_{2}+y_{1}x_{2})
$$

ocean sealBOT
#

MisterSystem

prisma dove
#

Can you see it now?

serene linden
#

Ohhh, yup.

#

Definitely

prisma dove
#

You have seen

#

when you learned about complex numbers

#

Did your teacher talked about polar form?

#

And how complex numbers can be identified with points in the plane?

serene linden
serene linden
prisma dove
serene linden
#

I see the connection between your explanation and the imaginary axis, and I am guessing that this image is a more formal way to define the imaginary axis. However, how does it connect to polar coordinates?

prisma dove
#

I just mentioned polar form

#

Because I think people recognize this geometrical interpretation of the complex numbers

#

More easily

#

When talking about polar form

#

But ofc, this is connected to the polar form.

#

This video is really good

#

It introduces C at the beginning

#

Using this construction

#

give it a check if you get interested

serene linden
#

Got it. Thank you for helping me clear up the confusion and for the references/resources. 🙂

prisma dove
#

Np 😄

alpine sable
#

question

#

whats 3x + 1?

remote heron
#

try drawing a picture maybe?

#

lmc

#

so just from the picture and idk if this helps

#

but you can get uhh

#

oh im not gonna type that

#

nah theyre not trivial usually

#

well they are and they arent

#

but you do have to keep trying stuff

#

lemme try scribblin

#

oh, nice

wary stream
#

By guessing?

#

Not what I got

#

That's what I got, using proper equations

prisma dove
#

$P(A \cup B) = P(A) + P(B) - P(A \cap B)$. But $P(A \cap B) = P(A) \cdot P(B)$ since they are independent events.
\
\
Now use the fact that $P(A) = 1 - P(A^{c})$ to conclude that $P(A) = \dfrac{2}{3}$

ocean sealBOT
#

MisterSystem

prisma dove
#

Can you continue from here?

wary stream
#

There is a mathematical approach that mistersystem stated and that was exactly what I did

prisma dove
#

Which you should be able to do since you know P(A \cap B) = P(A) P(B)

#

nice

unkempt hatch
#

is there a mistake in this?

#

the answer integrates 2 and the -8/sqrt(3x+4) terms independently. so the du occurs only on the -8 term

#

but why do i get a different answer if i consider both the terms together

mild tartan
#

oh..

wary stream
unkempt hatch
#

the answer kinda does this way. splitting the integral for both terms

unkempt hatch
robust phoenix
#

well hello there

unkempt hatch
#

hi

robust phoenix
#

is that true ?

#

do the 2 x's cancel each other out ?

maiden holly
#

What if x=0 opencry

unkempt hatch
shrewd prism
robust phoenix
shrewd prism
#

just replace x with a number and find out

robust phoenix
#

It actually is true

unkempt hatch
robust phoenix
#

alright

#

i will move

unkempt hatch
#

thanks

robust phoenix
#

I'm going to #help-9 have a good day

unkempt hatch
#

have a good day too!

unkempt hatch
distant horizon
#

so it would be 2/3 (3x+4) - 16sqrt(3x+4)/3

unkempt hatch
#

but the answer is 2x - 16sqrt(3x+4)/3 + c

distant horizon
#

and first part is 2x and you can use u sub for the rest

unkempt hatch
#

but why does not splitting the integral result in a completely different answer?

distant horizon
#

hmm

#

i couldnt figure that out

#

lemme check on my phone

#

nah i coudlnt get it

unkempt hatch
simple hamlet
simple hamlet
unkempt hatch
#

can you please take another channel

#

it's occupied

unkempt hatch
alpine sable
unkempt hatch
#

how does that apply here?

#

however, by this logic, collectively doing it must lead to the correct answer (which is not the case here)

#

oh ok. but my q is why does collectively doing it lead to the wrong answer?

#

however i think i have definitely seen cases where my approach works correctly (just not in this case)

#

take another channel

#

there is ongoing discussion

#

hmm ig

#

yeah

#

just remembered i had called helpers earlier. helpers, forgive me lol

vestal hollow
#

Can removable discontinuities still form vertical asymptotes?

#

Let h(x) = f(x)/g(x), where f and g are polynomials. There are three zeros of g, one of which is a zero of f, but if we factor f and g, we can cancel this common zero. So if we remove the common zero then our number of vertical asymptotes should just be 2 right?

#

Let me try it in Desmos

#

Ah yeah it seems you're right

gray isle
#

@unkempt hatch can you repost your question and issue you're having

unkempt hatch
#

sure

gray isle
#

It doesn't really matter if you split the integral here

unkempt hatch
#

basically, my q is what's the mistake here?

unkempt hatch
gray isle
#

you forgot the +C and where's the rest of your work

unkempt hatch
#

wdym by the rest of my work

gray isle
#

well the original integral is in x
your current result is in u

#

your final result should be in x

unkempt hatch
#

u just substitute u as 3x+4 right?

unkempt hatch
gray isle
#

don't forget about the constant of integration

alpine sable
#

hello

unkempt hatch
#

ohk, even with adding c my answer is not correct

gray isle
#

note that 2/3 (3x+4) can be expanded

#

and the sum of constants is just another constant

unkempt hatch
#

ahhhh ok. so when i expand and get +8, it just morphs into +c (in the case of the correct answer: 2x - 16sqrt(3x+4)/3 + c)?

alpine sable
#

How do you go from radians to degrees?

#

and vice versa

unkempt hatch
#

please take another channel. this is occupied

alpine sable
#

what's theta?

#

okay

gray isle
#

yeh pretty much. you should reach the same result.

unkempt hatch
#

oh ok. got it. thank you so much!

#

lol... smh

alpine sable
#

yeah just talk here

#

but i'll be back just write the answer and i'll look later

alpine sable
#

Is this channel occupied?

#

Cool

#

What is unique factorization Theorem and product notation

#

M2.3

#

I know all of it but that just sound weird

#

Is that the factor^2 (or the number the factor repeated)

#

What is that

#

I have never seen this sign before

#

And How exactly can i use this without a calculator

#

Yeah

#

This is a specification for exam without a calculator

#

Can you please tell me what 2n say and why n=1 and why 10

#

And what to do if there is somthing on the left

#

Like 4-

#

Or -2

placid zinc
#

You're multiplying 10 different numbers, and they follow the pattern of 2n, when you plug n = 1,2,3...9,10

alpine sable
#

So the 10 is 10 numbers, 2n is how I progress which is multiply the previous number plus 2 and n=1 is the start point ?

#

Alright

#

So what's the upper bound ?omg I feel so stupid

#

Is it upper and lower bound

reef urchin
# alpine sable

so for this question, u start from n=1 and u stop at when n=10

alpine sable
alpine sable
#

So what are you trying to say

#

What's upper bounds

#

No

#

It is the sum of numbers

#

It is the sum of numbers you multiply

gray isle
#

why are you using the word sum here

alpine sable
#

Yeah that's wrong

#

Sorry guys

#

10 is telling us how much we are going to go

gray isle
#

The word is product

alpine sable
#

N=2 then we will probably start like this

#

Wait a minute

reef urchin
#

if the lower bound n=5, and the upper bound is 10, you’d start at n=5 to n=10

alpine sable
#

How about this one

#

There is a -2 at the left

#

What is that

#

No

gray isle
#

-2 is being multiplied to the whole thing

alpine sable
#

But how can I get the pattern here

#

The next one will be 3×what ?

#

9?

#

Guys?

#

Sorry

#

Why we added 1

#

The first one would be 3×3-1 you made the second one 3×4-1

reef urchin
#

so we’d go from x=3 to x=4 to x=5 ... until u get to x=7

alpine sable
#

He didn't say n+1

gray isle
#

by definition of the notation

alpine sable
#

Who said x should increase by 1 every time why not two

alpine sable
#

What property why you assume I know that

gray isle
#

have you done stuff with summation or sigma notation before?

alpine sable
#

I don't remember

#

Where can I get the basics I need

gray isle
#

look up summation notation for the bare basics of this type of notation

alpine sable
#

Wait a minute I only saw the sum sign in A level biology

#

Nah I finished it with A*

#

No just the biology

#

You can take it as one year

#

No you can choose

#

It's A level as and a2

#

A2

#

Yeah

#

You can do it in one year

red phoenix
#

A level maths doesn’t do the sun sign

#

Only further maths

#

Apart from statistics tho

#

For maths statistics is part of it

#

Which kinda sucks

#

I suppose, but the a level module makes you memorise the damn sampling techniques

desert moon
#

how do you choose which one will be -lambda and which one will be +lambda?

#

in the 2 ode that you make, one will have positive coeff, the other will have -ve coeff

#

so one sol will have sine cos, and the other sinh cosh

alpine sable
gray isle
#

Khan for basics
Prof Leonard for more depth

fervent anchor
#

Partial DE

dark talon
alpine sable
#

Ummm youtube is so confusing

alpine sable
gray isle
#

the explaination/notation should be pretty simple

#

still not sure what your issue is with understanding it

alpine sable
#

I just want to be academically aware of details

#

Videos on YouTube don't even mention the terminology

gray isle
#

what videos are you watching

alpine sable
#

I finished the khan academy 3 min video and now watching the organic chemistry tutor

#

They look like explaining it just for fun not for exams

gray isle
#

How would expect the explaination for exams to be different?

#

Org Chem is pretty good too

alpine sable
#

Like in text books contain the slightest details and the people who wrote are expert in exams so they know hoe to portray it from the beginning with suitable terminology to the academical level needed for exams

#

We all know youtube is just an extra thing it can't be the main

solar pebble
alpine sable
#

Signa

#

Hehehe

solar pebble
#

@alpine sable British Mathematics Syllabus is an absolute pisstake

red phoenix
#

🌞

solar pebble
#

Sigma does not look like the sun thinkies

red phoenix
#

I’m on phone

#

Auto correct

alpine sable
gray isle
#

if you're not satisfied with what YouTube provides, do you have a textbook with such explainations?

alpine sable
#

No I am asking you if you know any

gray isle
#

but it really feels like you're trying to overcomplicate things

alpine sable
#

I need to know concepts and vocabulary of product notation and unique prime factorisation

gray isle
#

and like I mentioned, product notation shouldnt be that hard to grasp

#

$\prod_{n=1}^{4} n$

ocean sealBOT
#

ℝamonov

gray isle
#

e.g the above would represent
1 * 2 * 3 * 4

alpine sable
#

So product notation is like sigma notation but *

gray isle
#

yes

alpine sable
#

How can you solve this

red phoenix
#

Same way as before

#

It wants you to multiply

alpine sable
#

8^7 ?

red phoenix
#

Yes

alpine sable
#

My calculator has no product notation

#

WHy did he add 0x?

#

This channel is occupied

#

As you see

#

SO i dont udrestand from where this 0x are gotten

gray isle
#

simplify by hand

alpine sable
#

So what about unique prime factorisation

gray isle
#

and use the calculator to evaluate when needed

#

what about it?

alpine sable
#

What does it mean

gray isle
#

expressing integers as a product of primes

alpine sable
#

Yeah we need the unique way of it

gray isle
#

e.g 6 is the product of the primes 2 and 3
hence its unique prime factorisation is 2 * 3

alpine sable
#

That's just the prime factorisation and I know I

#

It

#

What is the unique prime factorisation

gray isle
#

The prime factorisation is inherently unique

#

unique is an unnecessary word being added on

alpine sable
#

But in M2.3 it said prime factorisation once and another time unique prime factorisation Theorem

#

Use the concepts and vocabulary of prime numbers, factors (divisors), multiples, common
factors, common multiples, highest common factor, lowest common multiple, and prime
factorisation (including use of product notation and the unique factorisation theorem)

gray isle
#

well the unique prime factorisation theorem just states that the prime factotisation is unique

alpine sable
#

Why is it in unique please involve concepts and vocabulary

gray isle
#

unique as in there is only one

#

there is only one prime factotisation for each integer greater than 1

alpine sable
#

I looked it up and that's really disappointing

#

It's not unique

#

What next?

#

-x/xˇ3 = xˇ-2

#

correct?

#

It is not root))

gray isle
#

not sure what you mean

#

they introduced all those terms with 0 to keep terms aligned and so that you don't make mistakes like what you just did

#

in fact I don't even know what you did

#

$ax^m - bx^n \neq (a-b)x^{(m-n)}$

ocean sealBOT
#

ℝamonov

alpine sable
#

These terms ?

gray isle
#

yes

alpine sable
#

Why he keeps those

gray isle
#

note how in their work all their terms align nicely

#

so when they're doing subtraction, they're actually subtracting like terms

alpine sable
#

Yes, but i still do not understand why he keeps those?))

#

THis is out of my mind

gray isle
#

well depending on your divisor, you may not know if they're needed.
but in general you should do it anyway

alpine sable
#

So, when he subtracted first 0x with power term, the others delete after that?

gray isle
#

or leave a decent gap

#

wdym

alpine sable
#

?

#

So , this example looks like that

#

0x he added

gray isle
#

uh huh...and?

alpine sable
#

So, when he subtracted first 0x with power term, the others delete after that?

gray isle
#

not sure what you mean

#

wdym subtracted the first 0x with power term

alpine sable
#

So when he did this move

#

after this others 0x i need to forget?

#

yes?

gray isle
#

wdym by others 0x

alpine sable
#

what is wdym?

gray isle
#

wdym means what do you mean

alpine sable
#

0x are the terms he added to ease this problem

#

so i asked

#

Whe he did 0xˇ3 -3xˇ3

#

Others are romved after that_

#

?

gray isle
#

you were being unclear by not writing the power

#

gaps are implied to be 0

#

the terms are already in the first row to indicate the powers of each column so it is unnecessary to write them out every single time

#

the main purpose of writing them at the start was to keep everything aligned

alpine sable
#

So, It is important to know this?

#

Where Is it neded?

#

))

gray isle
#

where is what needed?

alpine sable
#

Dividing by a Binomia

#

How often do you use it_

gray isle
#

It's quite common in math courses

alpine sable
#

So, ok , thanks

#

how do you convert from decimals to radians?

#

degrees*

gray isle
#

multiply by pi/180°

alpine sable
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yeah but can u tell me why it's like that

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because of the unit circle?

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and I also need the formula for vice versa

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2pi because of the circumference of the unit circle and there is also 360 degrees there

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pi means half the circle, which is also 180 degrees. 1 degree is therefore pi/180

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180 pieces of pi makes a pi

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180 degrees make a pi u mean?

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but i don't understand the formula tho