Items tagged with dot


Hi guys,

I run my code and after a point all the numerical values are followed by a dot. Why is that? Also the symbolic variables have a 1. before them.

Thanks a lot!

I am trying to simplify noncommutative expressions that use the 'dot' operator: `.`. The following is a minimal example:

a2 . (1/(a2 . (1/a1) . a2)) . a2, which evaluates to:   a2 . (1/(a2 . (1/a1) . a2)) . a2

This should simplify to 'a1', as I am expecting `.` to work like noncommutative multiplication. If there is any way to define this behavior I would appreciate some help. Alternatively, I would also be happy with reworking 'simplify' to work in this scenario. If it helps, I am working with finitely presented groups. If you see the Maple package 'GroupTheory', you'll see that the 'Group' function has this built in. If we input generators and relators it will simplify expressions of the above type, so I know it can be done!

Lastly, I would prefer displaying '1/a1' as 'a1^-1', but that is just for aesthetics.

Here is a minimal document:

I want to make a dot product like

Eq6 := (sum(delta[i].v[i], i = 1 .. 3)).(sum(delta[j].w[j], j = 1 .. 3))

and get the complete result like

Eq7 := v[1].w[1]+v[2].w[2]+v[3].w[3]

but instead I get

Eq6 := ((Vector(3, {(1) = 1, (2) = 0, (3) = 0})).v[1]+(Vector(3, {(1) = 0, (2) = 1, (3) = 0})).v[2]+(Vector(3, {(1) = 0, (2) = 0, (3) = 1})).v[3]).((Vector(3, {(1) = 1, (2) = 0, (3) = 0})).w[1]+(Vector(3, {(1) = 0, (2) = 1, (3) = 0})).w[2]+(Vector(3, {(1) = 0, (2) = 0, (3) = 1})).w[3])

Is there a way to force the dot product operation all the way?

I define unit vectors as

delta[1] := Vector(3, {(1) = 1, (2) = 0, (3) = 0})

delta[2] := Vector(3, {(1) = 0, (2) = 1, (3) = 0})

delta[3] := Vector(3, {(1) = 0, (2) = 0, (3) = 1})

Then I manually take the dot product as

Eq3 := delta[1].delta[1]+delta[1].delta[2]+delta[1].delta[3]+delta[2].delta[1]+delta[2].delta[2]+delta[2].delta[3]+delta[3].delta[1]+delta[3].delta[2]+delta[3].delta[3]

and get

Eq3 := 3

But when I do this

Eq4 := sum(sum(delta[i].delta[j], j = 1 .. 3), i = 1 .. 3)

I get

Eq4 := Vector(3, {(1) = Vector(3, {(1) = 1, (2) = 1, (3) = 1}), (2) = Vector(3, {(1) = 1, (2) = 1, (3) = 1}), (3) = Vector(3, {(1) = 1, (2) = 1, (3) = 1})})

How can I make Maple give me the first result using the sum command?


I'm trying to add a label to a plot and need the derivative to be represented as a dot. My typesetting rules are set to extended, and it works in a worksheet but not in the plot. See attached image. The code to generate it is:

#the output is shown with a dot over phi

#derivative in label not shown as a dot
plot(sin( t), t=0..10, labels=["t", typeset(diff(phi(t),t))], labeldirections=[horizontal, vertical]);

any ideas?



this seems to work... ( i will leave this question here as it might come in handy to someone else).

plot(sin( t), t=0..10, labels=["t", Typesetting:-Typeset(diff(phi(t),t))], labeldirections=[horizontal, vertical]);

Is it a bug that using the first variant does not work? any ideas from the experts?

Dear all,

I woul line integrate e gradient moltiply to a vector. I will try to explain better.

I have define this function:


and I have a vector a


I would like to applu a dot product between the gradient of phi an the vector and integrate the results. 

I have already try in many way but without succeed. Someone could please help me?





the final result I want to get should be b*x

Thank you.


I was wondering how I could assign small angel assumptions so that I could simplify an equation of motion to solve for theta double dot. Thank you for your help.


Equation Manipulation

-assumptions- small angel







diff(`ϑ`(t), t) := 0


diff(x(t), t, t) := (H+u)/M

I*(diff(`ϑ`(t), t, t)) = [m*(-l*(diff(`ϑ`(t), t))^2*cos(`ϑ`)-l*(diff(`ϑ`(t), t, t))*sin(diff(`ϑ`(t), t)))-m*g]*l*sin(`ϑ`)+[m*(l*(diff(`ϑ`(t), t))^2*sin(`ϑ`)-l*(diff(`ϑ`(t), t, t))*cos(diff(`ϑ`(t), t))+diff(x(t), t, t))]*l*cos(`ϑ`)


Error, (in isolate) unable to isolate diff(diff(`ϑ`(t), t), t)






While substituting expressions for θ(t),θ'(t),θ''(t) with some rather simple polynoms (see attached demonstration), the result icludes terms such as "·2" or "θ1·" (see terms multiplying ε8 and ε7in result for C1). It seems MAPLE treates the "·" sign as a variable/constant instead of as an operator. What am I doing wrong?


I wish to use the 'Numeric Formatting' feature on some results in Maple, to show the correct significant figures in the results. But when I apply Numeric Formatting to any result, the decimal seperator changes from the usual dot (.) to a comma (,). How can I keep the dot as decimal seperator while applying the correct significant figures?



The "." notation for the dot product of Vectors is very convenient and intuitive.  For example:

> <1,2,3> . <1,1,1>;


One sometimes annoying feature of it, however, is that by default Maple is using a dot product (suitable for Vectors with complex scalars) that is conjugate-linear in the first argument.  But let's say you will only be working with real scalars.  There's no problem if your Vectors have numeric entries, but...

A short remark. This would be a blog entry if those still existed.

I am comparing plot,options.

The style=point option has versatile options for symbols, their sizes, the number of points:

  , 'style' = point
  , 'numpoints' = 50
  , 'symbol' = solidcircle
  , 'symbolsize' = 8


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