@Carl Love 

it'better than Has if the variables are indexed; in this case I have to search a string

@nm Thanks for help

@dharr 

Thanks for your help, it works fine.

But how can I get the values of sol[2] because sol[2,1] returns x=3 and not 3.

@Rouben Rostamian  

Dear Rouben thanks for reply.

Until now I preferred e.g.

with(Student:-MultivariateCalculus)

T_len := sqrt(simplify(DotProduct(T, T)))

@Rouben Rostamian  

Dear Rouben, thanks for your extensiv help.

What's the meaning of "T^+" in T__len := sqrt(simplify(T^+ . T));

For me, it's new.

@dharr 

Thanks for reply. Yes, the shortest path connecting any two surface points.

@Scot Gould 

Dear Scot, thanks for your help. Now it works. I didn´t know that I can address by using arrowList[1, 1][1];
arrowList[1, 2][1];

Thanks

@Thomas Richard 

Dear Thomas, thanks for your response.

To be honest I don't understand the concept of Maple API Integration. I developed several Java plugins in Eclipse to integrate Visual Paragdigm by using it's API library.

I'm using a MacBook Pro and I have no idea how to call the Maple APIs using Eclipse.

Best regards, Dieter

@Thomas Richard 

@Carl Love Also thanks for help

@acer Thanks for help, it works fine

@Rouben Rostamian  

Tahnks a lot - that's what I'm looking for.

@Rouben Rostamian  

Dear Rouben, thanks for reply. I simply like to plot the vector coordinates of a point.

points := pointplot3d([P, Q, R, M], color = [green, blue, red, black], title = "P", symbol = cross, size = [1, 1], labelfont = [Courier, bold, 40])

And additionally I would like to plot the coordibates of the points.

Thanks for help.   

@dharr much easier