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input for parametric equation for vector
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hi,
I need to input this parametric equation for a rotating vector
r(t)=r [u.cos(wt)+v.sin(wt)]
r(t) vector function
u, v : unit vectors for X and Y axes
w angular speed
the function Curve[.....,t,] traces me a circle but that's not what I need
How can I proceed ?
thanks
I know the product k*u (scalar times vector) works well but not in this case.
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hello
do you mean
a slider (angle or number)
r number
A point
vector[A,A+(r;a)]
saludos
no I don't want to write a polar coordinate vector
i want to write an equation r(t) where r is the vector vs time in an 2dimension reference given by u and v , unit vectors.
this must give me a rotating vector in function of time t
Hi, using Mathmagic's advice is basically the best you can do in your case. Maybe you want to do slight modifications:
t time (slider)
r radius (number)
w angular velocity (number)
r=u*cos(w*t)+v*sin(w*t)
The "t" parameter must come from a slider, you cannot write "r(t)" on LHS of the equation.
Cheers,
Zbynek
thanks both of you for your advices
t as a slider is a good idea to get around it.
but my idea is to to have a function with variable t that I can derivate to obtain the speed and the acceleration vectors.
I see there are derivative functions set in Geogebra I could use but only for classic functions with x but not parametric ones with t.
may be I have to write some program lines with javascript aside to take account of this possibilities.
best regards
jean
You can also define the paramtric curve
a=Curve[sin(p),cos(p),p,1,10]
t ... slider
w = Vector[a(t)]
hide a
and then use Derivative[a]. I remember creating a worksheet using Derivative o parametric curve: http://www.geogebra.org/for...
but I'm sure there are better examples around the forum.
thanks !
seems good !
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