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GeoGebra Topic Question English

How to find relative maximums and minimums of a sequence of points in list form?

jospercomp shared this question 2 years ago

Answered

l1=Sequence((i,sin(i)),i,0,10,0.01)

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Best Answer

rami ● 2 years ago

maybe this?

Files: ExtremumPntLst1...

Comments (8)

Michael Borcherds ● 2 years ago

Have you tried eg

Max(x(l1))

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jospercomp ● 2 years ago

This is Maximum Absolute. I am looking for Maximum Relative list. Maximum Relative is where there are concavity down. Minimum Relative is where there are concavity up.

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Seror ● 2 years ago

Max(Séquence(y(Elément(l1, i)), i, 1, 100))

Min(Séquence(y(Elément(l1, i)), i, 1, 100))

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jospercomp ● 2 years ago

This are only Maximum and Minimum Absolute. I want Maximum and Minimum Relative.

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rami ● 2 years ago ●

maybe this?

Files: ExtremumPntLst1...

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mathmagic ● 2 years ago

from rami's points other method

Files: foro.ggb

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jospercomp ● 2 years ago

I like their methods because they are very interesting and complicated. I had thought of something like this; but it does not work for cases where there is noise in the data. This only worked with charts with smooth data.

Maximum Local Lists

RemoveUndefined(Sequence(If(y(Element(l1, i - 1)) < y(Element(l1, i)) ∧ y(Element(l1, i + 1)) < y(Element(l1, i)), Element(l1, i)), i, 2, Length(l1) - 1, 1))

Minimum Local Lists

RemoveUndefined(Sequence(If(y(Element(l1, i - 1)) > y(Element(l1, i)) ∧ y(Element(l1, i + 1)) > y(Element(l1, i)), Element(l1, i)), i, 2, Length(l1) - 1, 1))

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Michael Borcherds ● 2 years ago

noise in the data

Then you need to fit a curve with one of the Fit...() commands first

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