exp=(E^(-(t/trMz)) (-Gr0 tr+coff1^2 Gr0 tr+Gr0 trMz-coff1^2 Gr0 trMz+2 coff1 Gr0 theta tr trMz wn-2 coff1^2 Gr0 theta tr trMz wn-2 coff1 Gr0 theta trMz^2 wn+2 coff1^2 Gr0 theta trMz^2 wn))/(Gr0Mz trMz (1-2 coff1 theta trMz wn+coff1^2 trMz^2 wn^2))+(I Sqrt[1-theta^2] (coff1 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn-2 coff1^2 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn+coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn-coff1 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn+2 coff1^2 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn-coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta wn-I coff1 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] wn+I coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] wn-I coff1 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] wn+I coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] wn-coff1^2 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 tr wn^2+coff1^4 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 tr wn^2+coff1^2 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 tr wn^2-coff1^4 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 tr wn^2+2 coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 tr wn^2-2 coff1^4 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 tr wn^2-2 coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 tr wn^2+2 coff1^4 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 tr wn^2+2 I coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] tr wn^2-2 I coff1^4 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] tr wn^2+2 I coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] tr wn^2-2 I coff1^4 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] tr wn^2+coff1^2 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 trMz wn^2-coff1^4 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 trMz wn^2-coff1^2 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 trMz wn^2+coff1^4 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 trMz wn^2-2 coff1^2 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 trMz wn^2+2 coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 trMz wn^2+2 coff1^2 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 trMz wn^2-2 coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta^2 trMz wn^2+2 I coff1^2 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] trMz wn^2-2 I coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] trMz wn^2+2 I coff1^2 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] trMz wn^2-2 I coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta Sqrt[1-theta^2] trMz wn^2+coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3-2 coff1^4 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3+coff1^5 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3-coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3+2 coff1^4 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3-coff1^5 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 theta tr trMz wn^3-I coff1^3 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] tr trMz wn^3+I coff1^5 E^(t (-coff1 theta wn-I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] tr trMz wn^3-I coff1^3 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] tr trMz wn^3+I coff1^5 E^(t (-coff1 theta wn+I coff1 Sqrt[1-theta^2] wn)) Gr0 Sqrt[1-theta^2] tr trMz wn^3))/(2 coff1 Gr0Mz (-1+theta^2) wn (1-2 coff1 theta trMz wn+coff1^2 trMz^2 wn^2))
I want to get the "I" coefficient. How to do?
exp // Im // ComplexExpand[#, TargetFunctions -> {Re, Im}] & // Simplify
$\endgroup$