equazione curva parametrica e punto sulla curva

luigi marino shared this question 3 years ago
Answered

Simona

ho riscontrato un problema su una curva parametrica:

(2cot(t),2sin(t)^2) Versiera

la curva viene tracciata correttamente, ma è impossibile inserirvi un punto.

Se si prova, le coordinate del punto sono al di fuori del reticolo (vicino al punto x=3 si

ottiene (31.79,0.01). Versione GeoGebra 5.0.451

Grazie per le tue risposte.

Ciao, Luigi

Comments (6)

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Visto.

Ho provato sia con il comando Punto( ) che con lo strumento.

Sento i capi e ti faccio sapere, grazie.

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For the devs - sorry, but I'm in a bit of a rush and can't talk directly:

Placing a point on the graph of (2cot(t),2sin(t)^2) by using the Point tool or command creates a point in (31.79,0.01) that can be moved along the witch (yes, it's an Agnesi witch curve) only to the right of that position.

Try placing a point with the Point tool in x=3: you keep getting (31.79,0.01)

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but if you write a = Curve((2cos(t) / sin(t), 2sin(t)²), t, 0, 2π) there is not problem

with a = Curve((2 / tan(t), 2sin(t)²), t, 0, 2π) it works nice also

siempre he pensado que usar cot() es un poco forzado

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Hi Juan

thank you

It is right, cot() is a bug for GeoGebra.

Curve have pole to infinity.

Best wishes, Luigi

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Thanks, fixed for next release (v452)

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Michael

thank you, I wait for the release 452.

Luigi

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