Solutions for Sample Exam II
4. Since the product of the growth rates is the growth rate of the product, it follows that nlogn grows faster than n (since logn grows faster than 1). We say that n is big O(nlogn).
5. {a,{a}}
6. Show that ~(AUB) subset (~A int ~B) x el ~(AUB) implies ~(x el AUB) implies ~ (x el A v x el B) implies x el ~A and x el ~ B implies x el ~A int ~B implies x el (~A int ~B) We leave (~A int ~B) subset ~(AUB) to you.
7. Let U be the array of integers from 1 to 10. Indicate that subsets of U contain elements from U if there is a one in position i of a string while a 0 in position i of the string indicates the element is not present. Thus U= 11 11 11 11 11 11 while A= 10 10 10 10 10.
8. Solve for x as a function of y x g(y)=(y-5)/3 The domain and range are all reals. The verification and plot are left to you.
9. The domain is x>-1 the range is y>0 (one way to find it is to compute the inverse function and find its domain.)
10. 2*2*2*...*2 (nfactors) < 1*2*3*...*n, if n>=4 Since 24>16 and every factor in the later is greater than every factor in the former. Later we will prove this formally by induction.