I have several functions (let a[x]
and b[x]
), defined as expressions with integrals and differentiations. I want to perform some manipulations with these expressions - for example, ask Mathematica to simplify a[x] + b[x]
without evaluations of integrals. Hold
doesn't works (as I tried) as I used to expand functions a[x]
and b[x]
first. I think, that I could replace Integrate
and D
with some meaningless heads integrate
and d
, and then expand functions with another meaningless symbol x
, but I can't achieve this, because Mathematica tries first to perform integrations and fails.
Example:
a[t_] := Integrate[t, {x, -∞, ∞}]
b[t_] := Integrate[t^2, {x, -∞, ∞}]
a[t]+b[t] (* this doesn't works, as it "evaluates" integrals;
I want to see simple sum *)
ADDED:
I want to see something like myIntegrate[t, {x, -∞, ∞}]+myIntegrate[t^2, {x, -∞, ∞}]
. Really, a and b are more complicated, and they contain more than one integrals. I want Mathematica to perform expression simplification keeping integrals unevaluated. I could manually modify definition for a and b, but they are rather complicated, and don't want to keep two copies (one with Integrate, and one with some myIntegrate).