OpenStudy (anonymous):

SET OPERATION U={p,q,r,s,t,u,v,w} A=r,s,t,u,w B=p,q,r,s,t C=q,s,u,w find each set C-B (A-C)-C-B (C-B)-A A-C (A-C)-(C-B)

7 years ago
OpenStudy (shadowfiend):

So, generally speaking, you have to ask yourself, `what does set difference mean'. Subtracting a set X from a set Y, Y - Z, means producing a new set that includes all of the elements in Y that are not in Z. As an example, I'll do the first one (C - B); let me know if that helps: C - B C consists of q s u w B consists of p q r s t B has q and s which are both in C. So, C - B is q s u w without q and s, so it is u and w: C - B = {u, w}

7 years ago