casperyc

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15 years, 8 days
University of Kent
Dr

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These are replies submitted by casperyc

OMG!!!

 

so which means i have typed it wrong for nearly half an hour...

 

So sorry about the carelessness...I was just pay attension to the code( brackets sorts of thing)

 

and

 

Thank you ,acer, for the x-dot thing, but how do  I add that to the following?

 

what have I tried is this

restart:with( DEtools ):  with( plots ): with(Typesetting):

ODE := diff( x(t), t$2 ) + epsilon*diff( x(t),t ) + x(t) = 0;
                  
SYS := [ diff( y(t), t ) + epsilon*diff( x(t),t ) + x(t) = 0,
         diff( x(t), t )                = y(t) ];

animate( DEplot,
           [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
             y=-3..3 ,labels=[x,typeset(`#mover(mi("x"),mrow(mo("⁢"),mo(".")))`)] ],
         epsilon=0..1, frames=20 );

 

it's both "x" on the x and y axises now...i need "x(dot)" on the y axis

 

thanks

 

OMG!!!

 

so which means i have typed it wrong for nearly half an hour...

 

So sorry about the carelessness...I was just pay attension to the code( brackets sorts of thing)

 

and

 

Thank you ,acer, for the x-dot thing, but how do  I add that to the following?

 

what have I tried is this

restart:with( DEtools ):  with( plots ): with(Typesetting):

ODE := diff( x(t), t$2 ) + epsilon*diff( x(t),t ) + x(t) = 0;
                  
SYS := [ diff( y(t), t ) + epsilon*diff( x(t),t ) + x(t) = 0,
         diff( x(t), t )                = y(t) ];

animate( DEplot,
           [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
             y=-3..3 ,labels=[x,typeset(`#mover(mi("x"),mrow(mo("⁢"),mo(".")))`)] ],
         epsilon=0..1, frames=20 );

 

it's both "x" on the x and y axises now...i need "x(dot)" on the y axis

 

thanks

 

Cool! I seem to have put it in the wrong place.

=================================

 

something strange  is going on here

 

 

typed by myself

>animate( DEplot,
>          [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
>             y=-3..3, scene=[x(t),y(t)] ,
>            
>             dirgird=[40,40]        ],
>          epsilon=0..1, frames=11 );

 

not working at all

Error, (in plots/animate) Option keyword (dirgird) was not in the allowed set of options, consisting of:  iterations, arrows, dirgrid, obsrange, scene, colour, linecolour, stepsize, a dependent variable range, a list of initial conditions or one of the allowed plot options: {animatefield, animate, axesfont, labelfont, linestyle, thickness, tickmarks, titlefont, resolution, xtickmarks, ytickmarks, dirfield, axes, color, colour, coords, font, scaling, style, title, view, numframes, animatecurves, symbol}, or one of the allowed dsolve/numeric options: {method, initial, value, abserr, control, ctrl, itask, maxder, maxfun, maxkop, maxord, maxpts, maxstep, minrel, minstep, relerr, start, stiff, corrections, errorper, startinit, stepsize, tolerance, maxfevals}

 

 

 copied from your post

>animate( DEplot,
>            [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
>              y=-3..3, scene=[x(t),y(t)],
>             
>              dirgrid=[40,40]      ],
>          epsilon=0..1, frames=11 );

 

working....

 

 

===========================================

One more question:

now the lable of y-axis is y(t)

is there actually a way to lable it "x (dot)" .

i mean the "dot on the x"

Thanks again.

Cool! I seem to have put it in the wrong place.

=================================

 

something strange  is going on here

 

 

typed by myself

>animate( DEplot,
>          [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
>             y=-3..3, scene=[x(t),y(t)] ,
>            
>             dirgird=[40,40]        ],
>          epsilon=0..1, frames=11 );

 

not working at all

Error, (in plots/animate) Option keyword (dirgird) was not in the allowed set of options, consisting of:  iterations, arrows, dirgrid, obsrange, scene, colour, linecolour, stepsize, a dependent variable range, a list of initial conditions or one of the allowed plot options: {animatefield, animate, axesfont, labelfont, linestyle, thickness, tickmarks, titlefont, resolution, xtickmarks, ytickmarks, dirfield, axes, color, colour, coords, font, scaling, style, title, view, numframes, animatecurves, symbol}, or one of the allowed dsolve/numeric options: {method, initial, value, abserr, control, ctrl, itask, maxder, maxfun, maxkop, maxord, maxpts, maxstep, minrel, minstep, relerr, start, stiff, corrections, errorper, startinit, stepsize, tolerance, maxfevals}

 

 

 copied from your post

>animate( DEplot,
>            [ SYS, [x(t),y(t)], t=0..10, x=-3..3,
>              y=-3..3, scene=[x(t),y(t)],
>             
>              dirgrid=[40,40]      ],
>          epsilon=0..1, frames=11 );

 

working....

 

 

===========================================

One more question:

now the lable of y-axis is y(t)

is there actually a way to lable it "x (dot)" .

i mean the "dot on the x"

Thanks again.

dose that mean it would be free?

 

if that;s the case , i dont think it's a good idea

usually i use Classical worksheet

it starts faster and mainly because the "font" is pretty

 

in standard mode

first of all ,starts too slow ( maybe not so important)

2nd, even i press ">" to get the command line , the "font"of the code is not very pretty

3rd, is it possible that to give more examples

 

is there something like a list of all small but useful commands

 

such as

" addmap ormap  map      is    coulditbe    "

 

 

my point is that sometimes , i want to do something,

just say   , check whether all members of a list is great than 0

i searched for nearly 1 hour , but dont really know what to type to search for in the help

 

than i posted for help, given "addmap" command, it's really easy to use, but hard to find.

 

 

I would try that when I get to the computer lab.

 

Just curious, usually I work in Classical Worksheet (which starts faster),

whenever I need help , use ?assume (for example)

 

this "help" and the help file in normal Maple, are they the same?

is that the "see the online help." refering to ?

 

which is better for an undergratudate to work in normally, the Classical Worksheet or the normal Maple progamme?

 

Thanks

 

 

PS:  Many of you may know that there are "some problems" with the "font" when work in normal Maple program mode. the codes are not as "pretty" as in Classical Worksheet

 

 

I would try that when I get to the computer lab.

 

Just curious, usually I work in Classical Worksheet (which starts faster),

whenever I need help , use ?assume (for example)

 

this "help" and the help file in normal Maple, are they the same?

is that the "see the online help." refering to ?

 

which is better for an undergratudate to work in normally, the Classical Worksheet or the normal Maple progamme?

 

Thanks

 

 

PS:  Many of you may know that there are "some problems" with the "font" when work in normal Maple program mode. the codes are not as "pretty" as in Classical Worksheet

 

 

Hi,

Just by accident, one hour before the deadline of my tutorial sheet. I saw a new reply of this post, which is REALLY fortunate!

 

I want to ask something which has confused many of us (classmates).

 

when I differentiate this equation

 

y^2+(x-c)^2=c^2   to get

 

2y*dy/dx +2x-2c=0  rearrange to get

 

dy/dx= (c-x)/y

 

then we take the the negative reciprocal

 

y/(x-c)

 

so the orthogoanl tracjetorise are solutions to

 

dy/dx=y/(x-c)

 

then i use DEplot to see that they are the straght lines with different slops all go through (C,0)

 

y this is wrong?

 

================

 

same problem here

 

for xy=c

 

at first , i rewrite it to

 

y=c/x   then

 

 

dy/dx=-c/x^2

 

so the orthogonal trajectories are solutions to

 

dy/dx=x^2/c  ( c is nonzero)

 

then I did it with another method

 

 

xy=c

 

y+x*dy/dx=0

 

dy/dx=-y/x

 

then take the ngative reciprocal and continue and plot ,

which seems to be the correct answer

 

y did the first method wrong?

 

 

Thanks so much!!

Hi,

Just by accident, one hour before the deadline of my tutorial sheet. I saw a new reply of this post, which is REALLY fortunate!

 

I want to ask something which has confused many of us (classmates).

 

when I differentiate this equation

 

y^2+(x-c)^2=c^2   to get

 

2y*dy/dx +2x-2c=0  rearrange to get

 

dy/dx= (c-x)/y

 

then we take the the negative reciprocal

 

y/(x-c)

 

so the orthogoanl tracjetorise are solutions to

 

dy/dx=y/(x-c)

 

then i use DEplot to see that they are the straght lines with different slops all go through (C,0)

 

y this is wrong?

 

================

 

same problem here

 

for xy=c

 

at first , i rewrite it to

 

y=c/x   then

 

 

dy/dx=-c/x^2

 

so the orthogonal trajectories are solutions to

 

dy/dx=x^2/c  ( c is nonzero)

 

then I did it with another method

 

 

xy=c

 

y+x*dy/dx=0

 

dy/dx=-y/x

 

then take the ngative reciprocal and continue and plot ,

which seems to be the correct answer

 

y did the first method wrong?

 

 

Thanks so much!!

i will think it through

thank you all

i will think it through

thank you all

however, is there a way to join the "arrows" together (just like plotting "all" the solutions in the range)?

 

thank you

however, is there a way to join the "arrows" together (just like plotting "all" the solutions in the range)?

 

thank you

i will try that

 

cheers

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