# SymbolicIntegration: can I do definite integrals?

**URL:** <https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951>\
**Category:** Modelling & Simulations\
**Created:** [January 8, 2026, 9:23am UTC](https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951 "2026-01-08T09:23:26Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![BLI](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bli/32/37206_2.png) [@BLI](https://discourse.julialang.org/u/BLI)\
**Post date:** [January 8, 2026, 9:23am UTC](https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951/1 "2026-01-08T09:23:26Z")

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Does SymbolicIntegration.jl support definite integrals? Including to +/- infinity? If so, what is the syntax for specifying integration bounds?

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**Author:** ![NoFishLikeIan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nofishlikeian/32/20917_2.png) [@NoFishLikeIan](https://discourse.julialang.org/u/NoFishLikeIan)\
**Post date:** [January 8, 2026, 10:04am UTC](https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951/2 "2026-01-08T10:04:15Z")

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`SymbolicIntegration.integrate` returns a `Symbolics.Num` which you can just evaluate with `Symbolics.evaluate`. The fundamental theorem of calculus should do the rest. For example

```julia
using SymbolicIntegration, Symbolics

@variables x
f = integrate(exp(-0.01 * x), x)

Symbolics.evaluate(f, Dict(x => Inf)) - Symbolics.evaluate(f, Dict(x => 0.))

```

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<div class="post-metadata">

**Author:** ![BLI](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bli/32/37206_2.png) [@BLI](https://discourse.julialang.org/u/BLI)\
**Post date:** [January 8, 2026, 1:15pm UTC](https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951/3 "2026-01-08T13:15:36Z")

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Ah. So it would be trivial to make a dispatch of `integrate` or add keywords `lower` and `upper`? I can live with `evaluate`, though.

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<div class="post-metadata">

**Author:** ![NoFishLikeIan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nofishlikeian/32/20917_2.png) [@NoFishLikeIan](https://discourse.julialang.org/u/NoFishLikeIan)\
**Post date:** [January 8, 2026, 1:29pm UTC](https://discourse.julialang.org/t/symbolicintegration-can-i-do-definite-integrals/134951/4 "2026-01-08T13:29:13Z")

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If you need a helper function, something like

```julia
function integratedefinite(f, x, a, b, method)
    F = integrate(f, x, method)
    return Symbolics.evaluate(F, Dict(x => b)) - Symbolics.evaluate(F, Dict(x => a))
end

```

works.