Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

automatic integral output simplification

  • To: mathgroup at smc.vnet.net
  • Subject: [mg115169] automatic integral output simplification
  • From: sean k <seaninsocal at gmail.com>
  • Date: Mon, 3 Jan 2011 03:57:03 -0500 (EST)

Hello group,

I want to get around the way Mathematica simplifies the output of an
integral.

For instance, Let's say you want to integrate -8 sin(2t) from t = {0,
t}

int1 = \[Integral]-8 Sin[2 t] \[DifferentialD]t
ul1 = int1;
ll1 = int1 /. t -> 0;
ul1 - ll1

yields the correct output.

-4 + 4 Cos[2 t]

But if i pose that integral with limits included in it, Mathematica
outputs

Integrate[-8 Sin[2 t], {t, 0, t}]

-8 Sin[t]^2

Now both these are correct, except when the definite integral is
evaluated, "mathematicamagic" kicks in.

My guess is that the coefficient in the argument for the sin function
is the culprit. What should I do here to make the Mathematica retain
the "2 t" inside the Sin?

Thanks in advance for any insights.

Sean






  • Prev by Date: Re: How to change the directory for the docs?
  • Next by Date: NDSolve, three 2-d order ODE, 6 initial conditions
  • Previous by thread: Re: Permanently install GenomeData
  • Next by thread: Re: automatic integral output simplification