# How can I make a result of expand\_derivative() callable

**URL:** <https://discourse.julialang.org/t/how-can-i-make-a-result-of-expand-derivative-callable/114323>\
**Category:** General Usage\
**Tags:** symbolics\
**Created:** [May 15, 2024, 9:11pm UTC](https://discourse.julialang.org/t/how-can-i-make-a-result-of-expand-derivative-callable/114323 "2024-05-15T21:11:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jcbritobr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jcbritobr/32/219275_2.png) [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Post date:** [May 15, 2024, 9:11pm UTC](https://discourse.julialang.org/t/how-can-i-make-a-result-of-expand-derivative-callable/114323/1 "2024-05-15T21:11:02Z")

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Hello, good evening.  
Im solving some differentiation and I dont know how to make a result from expand\_derivative function from Symbolics callable. This will enhance my workflow. Is there a way to do?

```julia
	@variables t
	i = 10-10ℯ^-2t
	Dt = Differential(t)
	current = Dt(i)
	@info current
	dft = expand_derivatives(current)
	@info dft # ******************* make dft callable
	md"""
	The result is $(20ℯ^-2) mA
	"""

```

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<div class="post-metadata">

**Author:** ![younes](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/younes/32/208506_2.png) [@younes](https://discourse.julialang.org/u/younes)\
**Post date:** [May 15, 2024, 9:35pm UTC](https://discourse.julialang.org/t/how-can-i-make-a-result-of-expand-derivative-callable/114323/2 "2024-05-15T21:35:23Z")

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maybe something like

```julia-repl
julia> dft = expand_derivatives(current)
20exp(-2t)

julia> dft_function = eval(build_function(dft, t))
#5 (generic function with 1 method)

julia> result = dft_function(1.0) # t = 1.0
2.706705664732254

julia> println("The result is $(result) mA")
The result is 2.706705664732254 mA

julia> 

```

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<div class="post-metadata">

**Author:** ![jcbritobr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jcbritobr/32/219275_2.png) [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Post date:** [May 15, 2024, 9:51pm UTC](https://discourse.julialang.org/t/how-can-i-make-a-result-of-expand-derivative-callable/114323/3 "2024-05-15T21:51:24Z")

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Hello. Thank you. Its a pretty neat solution.