unfortunately I spent an hour explaining my problem but lost all this work because the forum became unavailable. so now of the much shorten explanation. my problem is I have a beam with a couple, two loads, two supports and has the following moment equation:
c2 + 3 (-9 + x)^3 + 1/4 (-9 + x)^4 + 7/2 (-3 + x)^3 - 1/4 (-3 + x)^4 + c1 x - 12 x^2
to solve for c1 and c2 requires that I use 'singular functions' that is, the term drops out if it evaluates less than zero. In mathematica it looks like this
ycc[x_] :=
3 Max[0, (-9 + x)]^3 + 1/4 Max[0, (-9 + x)]^4 + 7/2 Max[0, (-3 + x)]^3 - 1/4 Max[0, (-3 + x)]^4 - 12 x^2 + c1 x + c2
NSolve[{0 == ycc[x] /. x -> 3, 0 == ycc[x] /. x -> 9}, {c1, c2}]
the results are: {{c1 -> 72., c2 -> -108.}}
my first expression above has been integrated twice generating the c1 and c2 terms, then I have to solve for them to have a complete equation that represents the deflection on the loaded beam.
so if I "just simplify" my first equation I will get the wrong values for c1 and c2 as they evaluate at different location differently along the beam and different terms will drop out at different locations on the beam. This is reason why I can't integrate a simplified form of the equation, as terms will be combined losing the ability to drop those terms (representing different loads) that come after the location I am determining the deflection in the beam.