DSolve::derarg
NDSolve::derarg
NDSolveValue::derarg
ParametricNDSolve::derarg
ParametricNDSolveValue::derarg
Here, Derivative[1][f[x]] indicates differentiation of a function named f[x] rather than the derivative of f evaluated at x:
DSolve[Derivative[1][f[x]] == f[x], f[x], x]This shows a valid input to DSolve:
DSolve[Derivative[1][f][x] == f[x], f[x], x]