Problem 1.1-1 Give a real-world example in which one of the following computational problems appears: sorting, determining the best order for multiplying matrices, or finding the convex hull.

Problem 1.1-1, Problem 1.1-2, Problem 1.1-3, Problem 1.1-4

Sorting: almost everything uses sorting. If a program is not using sorting then it just adds two number and returns 0; 

Matrix multiplication: 
  uhh, here's the hurt. I don't know off the top of  my head. Let me walk through the thinking. 

Matrices contain tabular data; data that is usually (who am I kidding?), always numbers. Numbers get multiplicated (yeah, I know) by a strange way of multiplication. What can numbers in sets represent? Points, 3D points, financial data ($$),  quantities of consumption (wild guess). And where can matrix multiplication be implemented? Graphic rendering, video rendering, stock exchange? 

Finding convex hull:

what the f is a convex hull?

In mathematics, the convex hull or convex envelope of a set X of points in the Euclidean plane or Euclidean space is the smallestconvex set that contains X. For instance, when X is a bounded subset of the plane, the convex hull may be visualized as the shape formed by a rubber band stretched around X