I am trying to simplify a simple expression,
(1/2)*((-Pi)*Abs[Sin[t]] -
Pi*Abs[Sin[t - 2*Pi]] -
2*Pi*Abs[Sin[t - Pi]] + 4)
i.e $$ \frac{1}{2} (-2 \pi \left| \sin (t-\pi )\right| -\pi \left| \sin (t-2 \pi )\right| -\pi \left| \sin t\right| +4) $$ for $0<t<\pi$, which should be $$ \frac{1}{2} (1 -4\pi |\sin(t)|)$$. I have tried various methods, like ComplexExpand and then FullSimplify[] which gives me,
(1/2)*Pi*Sqrt[Sin[t - 2*Pi]^
2] - Pi*Sqrt[Sin[t - Pi]^
2] + 2
i.e $$ -\pi \sqrt{((t-\pi ) \sin )^2}-\frac{1}{2} \pi \sqrt{((t-2 \pi ) \sin )^2}-\frac{1}{2} \pi \sqrt{(t \sin )^2}+2 $$ which I understand shouldn't further simplify as square-root brings in an ambiguity, somehow ComplexExpand is making the expression complicated.
Assuming[0 < t < Pi, (1/2)*((-Pi)*Abs[Sin[t]] - Pi*Abs[Sin[t - 2*Pi]] - 2*Pi*Abs[Sin[t - Pi]] + 4) // Simplify]
evaluates to2 - 2 Pi Sin[t]
$\endgroup$