Math 106-01: Calculus II: Reading Homework 3.2

1. The Definite Integral : what is the difference between the left- and right-hand sums? how are they written in sigma notation?
   
   1. Definition : how is the definite integral related to the left- and right-hand sums? what is a Riemann sum? the integrand of the integral?
      
      1. calculating : how might we calculate a definite integral? can definite integrals be calculated exactly?
         
      2. and areas : how are definite integrals related to area? what happens when the integrand of the integral isn't positive?