a. Suppose that an interest rate x follows the process
![](https://book.transtutors.com/qimg/3ea5d95a-f470-4a21-91bb-ff116ec129d1.png)
where a, x0, and c are positive constants. Suppose further that the market price of risk for x is λ. What is the process for x in the traditional risk-neutral world?
b. Prove that, when the security f provides income at rate q, equation (27.9) becomes ![](https://book.transtutors.com/qimg/581d360c-3365-4392-ac5d-b125324df6c7.png)
![](https://book.transtutors.com/qimg/f1359fc5-0073-4db1-bbf2-415e28fde45f.png)