Problem 1.2 [10 points] Purpose: Set theory review/practice. [Sipser] Write formal descriptions of the following sets. a. The set containing the numbers 2, 20, and 200. b. The set containing all integers with absolute value less than 3. C. The set containing all positive integers with absolute value greater than 3. d. The set containing the numbers 3, 9, 27, 81, .... e. The set containing nothing at all. Examples: "The set of non-negative integers." would be {0, 1, 2, 3, 4, 5, ...}; "Real numbers whose cosine is 1." would be { x in R. cos(x) = 1 }, where R = Reals