(1 point) For each of the following diffential equations, decide whether it is exact or not by computing the appropriate first order partial derivatives. If it is not exact, type N in the answer box. If it is exact, type in a function F(x, y) such that F(x, y(x))=C defines implicitly a solution of the differential equation.

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?