the integral is the area under the curve
from 0 to x
so whenever it goes under the curve, count it as negative
a.
x=0, that is from 0 to 0 so 0 total area
x=1, taht is a triangle, so 1/2 is the value
x=2, goes negative 1/2-1/2=0, so 0 is value
x=3, still negative so 1/2-1/2-1/2=-1/2, so -1/2 is value
x=4, cancels out all the negatives, so 1/2-1/2-1/2+1/2=0, 0 is the value
x=5, everything pervious cancels out to just find the area of that square and triangle which is 3/2 area
x=6, 2 more squares and another triangle so 4 squares or 4 units total
