## 962 Reputation

16 years, 119 days
University of Kent
Dr

## something about isoclines on direction f...

Maple
hello i was asked to draw direction field and some isoclines for some ODEs Now i have some problems: the equation is t*diff(x(t),t)-x(t)=0 and i use contourplot(x(t)/t,t=-10..10,x=-10..10); to draw the isoclines... however, the output is not quite as i expected, it looks like some curve because if i draw it by hand, i put dx/dt=x/t and set x/t=c ( c is some constants) then the graph should be some straight line what am i doing wrong??

Maple
Hey, I want to look into something about n! I wrote a procedure like: > myfactorial:=proc(N) > local ptlist,k: > uses plots: > ptlist:=NULL: > for k to N do > ptlist:=ptlist,(k,k!): > od: > pointplot([ptlist],color=red); > end: myfactorial(20); works fine myfactorial(50); and more than 50 it says floating point overflow.please shorten axes.. is there a way to make it work? and n! is defined as int(x^n*exp(1)^(-x),x=0..infinity); why the output is Gamma (n+1) insteas of 1? simplify(%/n!); # can give me "1" and how do i get maple to plot

## can i delay the output?...

Maple
Hi, I am just courious and I want to delay the output like: If I ask maple to do an integration, first it displays the question: Int(x,x); then after some time it displays the answer int(x,x); is there a way to do that?

## how do i evaluate in degrees ?...

Maple

Hi,

I want to evalute in degrees.

restart:with(Units[Natural]):

sin(45 * deg);  # it works

>alpha[1]:=4.25 * deg;
> theta[1]:=11.31 *deg;
> theta[2]:=78.69 *deg;
> alpha[2]:=-9.25 *deg;
> a:=1400.00;  #  a and b should be real values
> b:=509.90;

>-b*sin(alpha[2]+alpha[1]-beta[1]-theta[2])+b*sin(beta[1]-theta[2]):

Error, (in Units:-Standard:-+) the units `arcdeg` and `1` have incompatible dimensions

not working...

## can someone do this for me ,please?...

Maple
Hi, I really have no idea how to do that.. http://img228.imageshack.us/img228/2839/euleric0.jpg can someone give me some hint or example,please ? thanks so much. Chen
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