#graph help

88 messages · Page 1 of 1 (latest)

tawny blaze
sterile bladeBOT
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tawny blaze
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i made a mistake, i picked c and i only have one try left

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im pretty sure the answer is A, but i just want to make sure

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i got everything else correct

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wait

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im wrong it's B i think

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fuck

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i was wrong it was D

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i'm gonna retry the question

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Let me get up to the graph part

spring coral
# tawny blaze

First four are correct, but C won't work. Look at your conditions again.

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Ah, sorry, didn't see your comments.

tawny blaze
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i'm gonna retry that question later

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im on a crunch for time

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@spring coral

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Can u help me for this one?

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I put negative for C f'' but i think it's zero

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i only have one try left ion wanna get it wrong

spring coral
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(well, technically, it can be 0 even in this case, but this isn't what they had in mind, that's for sure)

tawny blaze
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oh

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so it'd be positive?

spring coral
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Are you sure?

tawny blaze
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i mean i put in negative already

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it said it was wrong

tawny blaze
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only answer left would be pos

spring coral
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Note that the second derivative shows the covexity of the function.

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f''(x) > 0 where f(x) is convex down and f''(x) < 0 where f(x) is convex up.

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At C the function is convex up, so f''(x) < 0.

tawny blaze
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yeah, so i thought that'd mean f' is also < 0 (i put negative)

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but it showed up as wreong

spring coral
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The values of derivatives don't explicitly depend on each other, they depend on how the function behaves in general.

tawny blaze
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Wtf

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wait so i was right

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i was so confused 😭

spring coral
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Let me check what you wrote for A and B, one sec.

tawny blaze
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This is another question

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so i know it's e,f, and g

spring coral
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Hm, yeah, they were correct. Oh well.

tawny blaze
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but i put (e,g) and it showed up wrong

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so what's the correct way to put that down

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would it be

spring coral
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f''(x) is positive in (e, g), not negative.

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Again, f''(x) is negative where f(x) is convex up.

tawny blaze
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omg i suck at this

spring coral
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You just need some practice.

tawny blaze
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soit'd be negative from

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a,d and h?

spring coral
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You need intervals, not points.

tawny blaze
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so

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[a,d], [h]

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oh

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wait

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(a,c),(c,d), (g,h)?

spring coral
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No.

tawny blaze
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fuck

spring coral
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(g, h) is correct. Not the two others, though.

tawny blaze
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(d,e), (g,h)
or
(b,c), (c,e), (g,h)

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i'm pretty sure it's (d,e), (g,h)

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is that correct

spring coral
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Yeah, nice!

tawny blaze
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😄

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so im assuming

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this would be what i selected

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the direct opposite of the last one

spring coral
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Yes.

tawny blaze
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f' increasing is just what f is increasing right?

spring coral
tawny blaze
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so everything > 0 as f is increasing f'

spring coral
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We know that if f(x) is increasing, then f'(x) > 0. Then, by differentiating both functions in that, we get that if f'(x) is increasing, then f''(x) > 0.

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So, f'(x) is increasing where f(x) is convex down.

tawny blaze
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so these three intervals

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a,b c,d e,f

spring coral
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No. It will be the same as for the question where f''(x) > 0, so still (a, c)⋃(c, d)⋃(e, g).

tawny blaze
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fuck

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i past the due date

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so it closed

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thank u for the help tho