The equation should be
μ ( t ) = exp ( ∫ ( ∂ g ∂ x − ∂ f ∂ t f ) ( t ) d t ) {\displaystyle \mu (t)=\exp \left(\int \left({\frac {{\frac {\partial g}{\partial x}}-{\frac {\partial f}{\partial t}}}{f}}\right)(t)dt\right)} .
