The process is given by $$dU_t=-\gamma U_t\mathrm{d}t+\sigma\mathrm{d}X_t$$
where $U_0 = u$ and $\gamma, \sigma$ are constants. Can you help me out to solve the equation for $U_t$ and find the expectation and variance?
Thank you.
The process is given by $$dU_t=-\gamma U_t\mathrm{d}t+\sigma\mathrm{d}X_t$$
where $U_0 = u$ and $\gamma, \sigma$ are constants. Can you help me out to solve the equation for $U_t$ and find the expectation and variance?
Thank you.
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You have $$dU_t + \gamma U_t dt = \sigma X_t$$ which is $$d(e^{\gamma t}U_t) = e^{\gamma t}\sigma dX_t$$ So $$e^{\gamma t}U_t - e^{\gamma 0}U_0 = \int_0^t e^{\gamma s}\sigma dX_s$$ i.e. $$U_t = e^{-\gamma t}U_0 + \int_0^t e^{\gamma (s-t)}\sigma dX_s$$
Can you go from here?