# Locus precision

alextrocado shared this question 2 years ago

Is there any way to increase locus precision?

Defined some conditions to plot a curve if the bound of conditions are near the curve, the branches of the curve doesn't appear...

1

ggb file

1

I'm not sure that the Product command can be applied to a list of inequalities

https://wiki.geogebra.org/e...

1

even if you use the condition directly the locus does not represent the curve correctly. Only if we increase the distance from the curve to the region does it correctly represent

1

it seems to me that I do not understand the problem. Can you say what object do you need here?

Files: foro.ggb
1

my file is working at your computer?

I want only define that curve inside the region and near the border it fails...The region is a condition to define the curve... Of course in this case the whole curve is within the region

1

negative, but I think Product(e) is wrong. I think you want with conditions.

but, on the other hand, I do not see the condition is necessary.

if you need a part of the curve you can do

Files: foro.ggb
1

Can you see the file you have uploaded now?

The curve doesn't appear near the bounds...

1

For my work i need that a curve have to be defined only inside a plane region...

1

your curve b is tangent to inequality in 6 points and all points in b are in a . you will not be sure if a point near to tangent point is inside or outside because it is rounding to zero and the equations are solved using the tangent method . I think you need more accuracy than PC can give. if the region is tangent to curve you will get parts anomalous

I hope some developer solves your question

1

Thank you for your opinion. My question was that how can i increase locus precision?

1

you can try a locus but I warn you it has some strange bugs

Files: foro.ggb
1

`For my work i need that a curve have to be defined only inside a plane region...`

• do you need it for a particular curve or all curves?
• what plane region (will it change?)
• why you need this (ie for calculation or just display etc)

1

I need this for all curves defined from polynomials of degree at most four bounded by plane regions defined by quadrics.

The curves and quadrics will depend from parameters that can change.

I need to use a more precise locus to my scientic work with GeoGebra not just for display...

1

Intersection points: https://www.geogebra.org/m/kgvtxhdz

You can shade the bit you don't want (in white?) like this:

``` -8x² - 8x y - 20y² + 12 <=0 || -64x² - 4x y - 128x - 67y² - 4y <= -208
```

1

in this case the curve by chance is all within the region. But I may have other cases where a part of the curve goes out of the region. And I'm not just concerned about representation.

It needed to represent a moving point on the part that is within that region to serve as the basis for Locus and if the curve is not well defined, the locus will not be either.

1

I think you need to parameterise the equation eg

https://www3.risc.jku.at/ed...

1

Many curves that i have computed can't be parameterized...

If the condition to define the curve is -8x² - 8x y - 20y² + 12 ≥ -1.5 && -64x² - 4x y - 128x - 67y² - 4y + 208 ≥ -6 (more margin in relation to the curve), the curve is correctly represented.

1

veo que hay veces que no se hace caso a mis sugerencias

1

Using the locus to generate the plane curve it seems to be better but near to the line x = 1 has a strange behavior

1

put the locus in layer 1 so the inequation goes to background

1

solved! Thank you