各位大神，求助一个问题，一个式子对t求导数后，出现了函数f上标的问题，同时出现了Subscript，这是什么意思？请大神帮助解答
E^-\!\(
\*SubsuperscriptBox[\(\[Integral]\), \(0\), \(t\)]\(c[
\*SubscriptBox[\(X\), \(\[Lambda]\)]] \[DifferentialD]\[Lambda]\)\) c[
Subscript[X, t]] f[Subscript[X, t], t] + E^-\!\(
\*SubsuperscriptBox[\(\[Integral]\), \(0\), \(t\)]\(c[
\*SubscriptBox[\(X\), \(\[Lambda]\)]] \[DifferentialD]\[Lambda]\)\) h[
Subscript[X, t], t] + E^-\!\(
\*SubsuperscriptBox[\(\[Integral]\), \(0\), \(t\)]\(c[
\*SubscriptBox[\(X\), \(\[Lambda]\)]] \[DifferentialD]\[Lambda]\)\) (
\!\(\*SuperscriptBox[\(f\),
TagBox[
RowBox[{"(",
RowBox[{"0", ",", "1"}], ")"}],
Derivative],
MultilineFunction->None]\)[Subscript[X, t], t] +
\!\(\*SuperscriptBox[\(Subscript\),
TagBox[
RowBox[{"(",
RowBox[{"0", ",", "1"}], ")"}],
Derivative],
MultilineFunction->None]\)[X, t]
\!\(\*SuperscriptBox[\(f\),
TagBox[
RowBox[{"(",
RowBox[{"1", ",", "0"}], ")"}],
Derivative],
MultilineFunction->None]\)[Subscript[X, t], t])

多谢，下次知道了