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Question: Eval Physics[diff]

Question:Eval Physics[diff]

Honigmelone 102 Maple
eval physics diff
April 11 2016
1

Hey all,

I want to symbolically differentiate a function and recalculate the result later. Here is what I have tried so far:


> 

restart;
> 

myexp:=dfdb+sthlong

dfdb+sthlong

 (1)
> 

b:=<b1(t),b2(t)>;

b := Vector(2, {(1) = b1(t), (2) = b2(t)})

 (2)
> 

dfdb:=Physics[diff]~(f(b),b)

dfdb := Vector(2, {(1) = (D(f))(Vector(2, {(1) = b1(t), (2) = b2(t)})), (2) = (D(f))(Vector(2, {(1) = b1(t), (2) = b2(t)}))})

 (3)
> 

f:=b->b(1)^2+b(2)

proc (b) options operator, arrow; b(1)^2+b(2) end proc

 (4)
> 

eval(myexp);  #actual result
> 

 

> 

 

sthlong+(Vector(2, {(1) = (D(f))(Vector(2, {(1) = b1(t), (2) = b2(t)})), (2) = (D(f))(Vector(2, {(1) = b1(t), (2) = b2(t)}))}))

 (5)
> 

dfdb:=Physics[diff]~(f(b),b):

> 

eval(myexp); #expected result

sthlong+(Vector(2, {(1) = 2*b1(t), (2) = 1}))

 (6)
> 

 


Download physics_diff.mw

I wonder if this is even possible, or if I missunderstand something. Can you please help me?

 

Thanks

 

Honigmelone
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