Question: Maple not evaluating an integral

Hi im using maple 16 and defined a vector field that is lengthy below,

(and yes i defined with(VectorCalculus), and SetCoordinates(cartesian(x,y,z)) (x,y,z is subscripted)


Full view of my screen with maple not integrating

And i am using a type of line integral for the work of a particle's path through a force field which i defined here as Z.

the integral has t limits of zero to 2 Pi and the inside the integral is the vector field multiplied by the derivative of the particle's path.

then r is the path of the particle and a is the derivative of the path with respect to t. Now i have tried setting Z.a result into another variable like L and using just that in the integral but that also does not give me a number result.  It seems that no matter what i do the only thing maple does is the dot product, and when i try the approximate command maple only approximates the value of 2Pi on my upper limit of integration.  If anyone can point me to what i may be doing wrong it would be much appreciated.


Thanks ahead of time

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