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piecewise integration

  • To: mathgroup at smc.vnet.net
  • Subject: [mg66944] piecewise integration
  • From: "Chris Chiasson" <chris at chiasson.name>
  • Date: Sun, 4 Jun 2006 02:01:25 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

The Integrate result seems pretty weak. Is there any way to obtain a
more explicit exact answer besides manually converting the Piecewise
function to two UnitStep functions? Can the same be done if the final
limit of integration is a variable?

in

load[x_]=-9*10^3*DiracDelta[x]+Piecewise[{{x*10*(10^3/3),0<=x<=3}}]-6*10^3*DiracDelta[x-5]//InputForm

out

-6000*DiracDelta[-5 + x] - 9000*DiracDelta[x] +
Piecewise[{{(10000*x)/3, 0 <= x <= 3}}, 0]

in

Integrate[load[x],{x,0,5}]//InputForm

out

Integrate[InputForm[-6000*DiracDelta[-5 + x] - 9000*DiracDelta[x] +
Piecewise[{{(10000*x)/3, 0 <= x <= 3}}, 0]], {x, 0, 5}]

-- 
http://chris.chiasson.name/


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