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#1 2024-03-23 05:05:20

mathxyz
Member
From: Brooklyn, NY
Registered: 2024-02-24
Posts: 1,053

Determine Local Minimum Value

Given f(x) = -x^3 + 12x, a local maximum value of 16 is said to be at 2.
Determine the local minimum value.


Note:

Does the local maximum value of 16 at 2 mean point (2, 16)?

If so, how does the point (2, 16) help me find the local minimum?

DO NOT USE CALCULUS.

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#2 2024-03-23 05:42:19

Bob
Administrator
Registered: 2010-06-20
Posts: 10,626

Re: Determine Local Minimum Value

Because it's a odd function so you can use the rotational symmetry.

B


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#3 2024-03-24 10:01:16

mathxyz
Member
From: Brooklyn, NY
Registered: 2024-02-24
Posts: 1,053

Re: Determine Local Minimum Value

Bob wrote:

Because it's a odd function so you can use the rotational symmetry.

B

Can you further explain rotational symmetry?

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#4 2024-03-24 14:03:01

amnkb
Member
Registered: 2023-09-19
Posts: 253

Re: Determine Local Minimum Value

FelizNYC wrote:

Given f(x) = -x^3 + 12x, a local maximum value of 16 is said to be at 2.
Determine the local minimum value.

since you can't use calculus then they probably wnat you to look at the picture
install the TI-84 emulator on your phone
plug -x^3+12x into [Y1=]
hit 'graph'
select 'calc'
choose 'minimum'

FelizNYC wrote:

Does the local maximum value of 16 at 2 mean point (2, 16)?

Yeh

FelizNYC wrote:

If so, how does the point (2, 16) help me find the local minimum?

I think youre supposed to assume mirrored symmetry
max at (2,16)
min at (-2,-16)?
this *is* the min but I don't know how you were supposed to know
THis mirroring doesn't always happen so you can't assume

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#5 2024-03-28 09:53:22

mathxyz
Member
From: Brooklyn, NY
Registered: 2024-02-24
Posts: 1,053

Re: Determine Local Minimum Value

amnkb wrote:
FelizNYC wrote:

Given f(x) = -x^3 + 12x, a local maximum value of 16 is said to be at 2.
Determine the local minimum value.

since you can't use calculus then they probably wnat you to look at the picture
install the TI-84 emulator on your phone
plug -x^3+12x into [Y1=]
hit 'graph'
select 'calc'
choose 'minimum'

FelizNYC wrote:

Does the local maximum value of 16 at 2 mean point (2, 16)?

Yeh

FelizNYC wrote:

If so, how does the point (2, 16) help me find the local minimum?

I think youre supposed to assume mirrored symmetry
max at (2,16)
min at (-2,-16)?
this *is* the min but I don't know how you were supposed to know
THis mirroring doesn't always happen so you can't assume

Where are we going with this situation?

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