List x1, x2, x3, x4 where xi is the left endpoint of the four equal intervals used to estimate the area under the curve of f(x) between x = 4 and x = 6. a 4, 4.5, 5, 5.5 b 4.5, 5, 5.5, 6 c 4.25, 4.75, 5.25, 5.75 d 4, 4.2, 5.4, 6

Option A. 4, 4.5, 5, 5.5

Step-by-step explanation:

Left point: a=x=4

Right point: b=x=6

Range: r=b-a→r=6-4→r=2

Width of each of the four equal intervals: w=2/4→w=0.5

The first left endpoint is x1=a→x1=4

The second left endpoint is x2=x1+w→x2=4+0.5→x2=4.5

The third left endpoint is x3=x2+w→x3=4.5+0.5→x3=5

The fourth left endpoint is x4=x3+w→x4=5+0.5→x4=5.5

Then, the list is: x1, x2, x3, x4 = 4, 4.5, 5, 5.5