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he population density (in people per square kilometer) in a rural town is a func

ID: 2893418 • Letter: H

Question

he population density (in people per square kilometer) in a rural town is a function p(r)p(r) of distance rr (in kilometers) from the center of this town --- the following table has some values of this population density function.

Population Density

Estimate the total population within 1.2 kilometers of this town's center by averaging the left- and right-endpoint approximations of an appropriate definite integral.

Total population (within 1.2 km) is approximately

  rr   0 0.2 0.4 0.6 0.8 1 1.2   p(r)p(r)   127 103.2 81.8 69.4 53.8 45.1 37.3

Explanation / Answer

here x = 0.2

Left endpoint approximation L = p(0) * x + p(0.2) * x + p(0.4) * x + p(0.6) * x + p(0.8) * x + p(1) * x

==> L = 127 * (0.2) + 103.2 * (0.2) + 81.8 * (0.2) + 69.4 * (0.2) + 53.8 * (0.2) + 45.1 * (0.2)

==> L = 96.06

Right endpoint approximation R = p(0.2) * x + p(0.4) * x + p(0.6) * x + p(0.8) * x + p(1) * x + p(1.2) * x

==> R = 103.2 * (0.2) + 81.8 * (0.2) + 69.4 * (0.2) + 53.8 * (0.2) + 45.1 * (0.2) + 37.3 * (0.2)

==> R = 78.12

Average = (L + R)/2 = (96.06 + 78.12)/2 = 87.09

Hence approximate population within 1.2 km = 87.09