Math 233 Unit 5 Integration Individual Project Assignment

Page 1 Of 2math233 Unit 5 Integrationindividual Project Assignment V

Evaluate the following integrals:

  • \(\int (5x^4 - 2x^2 + 2x) \, dx\)
  • \(\int \left(\frac{1}{\sqrt{x^3}} + 5x^5 \right) dx\)
  • \(\int \frac{1}{7x} \, dx\)
  • \(\int (9x^2 - 8x + 1) \, dx\)
  • \(\int \frac{1}{(x+5)^3} dx\)

Consider the graph below, and answer the following:

  1. Set up the definite integral to calculate the area of the shaded region on the graph, where the red curve is the graph of the function \(f(x) = 0.5x^2 + x + 2\), for \(1
  2. Find the area of the shaded region.

The velocity (in feet per second) of a moving object at various times \(t\) (in seconds) has been recorded and is modeled by the function \(v(t) = 9t^2 + 4t\), with an initial position of 0 feet.

  1. Find the position function \(s(t)\), where \(s\) is in feet.
  2. Find the position of the object after 2 seconds.
  3. Find the change in position of the object between 5 and 10 seconds.

Suppose you are tasked with modeling a city’s population growth. The growth rate is given by \(r(t) = 200 \times 1.075^t\), where \(t\) is years from 2010. The current population is 75,000.

  1. Choose three values of \(t\) between 5 and 20.
  2. Find the function \(P(t)\) that models the population growth.
  3. Complete a table with the three chosen \(t\) values, calculating the corresponding population \(P(t)\).
  4. Interpret the meaning of the integral \(\int 200 \times 1.075^t \, dt\) in the context of population modeling.

Paper For Above instruction

This comprehensive mathematical analysis explores a sequence of integral calculus problems, applied to various real-world contexts such as area calculation, motion, and population growth modeling. Each problem demonstrates different integral concepts, from indefinite integrals to applications involving physics and demographic analysis. Through detailed explanations and calculations, this paper aims to provide clarity on the use of integration in varied scenarios, emphasizing the importance of understanding integral setup, calculation, and interpretation.

Evaluation of Integrals

The indefinite integrals incorporate polynomial, rational, and algebraic functions. The first integral, \(\int (5x^4 - 2x^2 + 2x) \, dx\), involves straightforward power rule integration. Integrating term-by-term yields:

\[

\frac{5}{5} x^{5} - \frac{2}{3} x^{3} + x^{2} + C = x^{5} - \frac{2}{3} x^{3} + x^{2} + C.

\]

The second integral, \(\int \left(\frac{1}{\sqrt{x^3}} + 5x^5 \right) dx\), involves simplifying the first term:

\[

\frac{1}{\sqrt{x^3}} = x^{-\frac{3}{2}}.

\]

Applying power rule:

\[

\int x^{-\frac{3}{2}} dx = \frac{x^{-\frac{1}{2}}}{-\frac{1}{2}} = -2 x^{-\frac{1}{2}} + C.

\]

For the second term:

\[

\int 5x^5 dx = 5 \times \frac{x^{6}}{6} = \frac{5}{6} x^{6} + C.

\]

Hence, the entire integral evaluates to:

\[

-2 x^{-\frac{1}{2}} + \frac{5}{6} x^6 + C.

\]

The third integral:

\[

\int \frac{1}{7x} dx = \frac{1}{7} \int \frac{1}{x} dx = \frac{1}{7} \ln |x| + C.

\]

The fourth integral:

\[

\int (9x^2 - 8x + 1) dx = 3 x^3 - 4 x^2 + x + C.

\]

The fifth integral:

\[

\int \frac{1}{(x+5)^3} dx = -\frac{1}{2 (x+5)^2} + C,

\]

where I used substitution \(u = x + 5\), \(du = dx\), leading to \(\int u^{-3} du = - \frac{1}{2} u^{-2}\).

Calculating Area Under a Curve

To find the area of the shaded region bounded by the curve \(f(x) = 0.5x^2 + x + 2\) over \([1, 5]\), we set up the definite integral:

\[

A = \int_{1}^{5} (0.5x^2 + x + 2) dx.

\]

Evaluating:

\[

\int 0.5x^2 dx = \frac{0.5}{3} x^3 = \frac{1}{6} x^3,

\]

\[

\int x dx = \frac{x^2}{2},

\]

\[

\int 2 dx = 2x.

\]

Therefore,

\[

A = \left[\frac{1}{6} x^3 + \frac{x^2}{2} + 2x \right]_{1}^{5}.

\]

Calculating at \(x=5\):

\[

\frac{1}{6} \times 125 + \frac{25}{2} + 10 = \frac{125}{6} + 12.5 + 10,

\]

and at \(x=1\):

\[

\frac{1}{6} \times 1 + \frac{1}{2} + 2 = \frac{1}{6} + 0.5 + 2.

\]

Subtracting:

\[

A = \left(\frac{125}{6} + 12.5 + 10\right) - \left(\frac{1}{6} + 0.5 + 2\right) = \left(\frac{124}{6} + 22.5\right) - \left(\frac{1}{6} + 2.5\right) = \frac{124 - 1}{6} + (22.5 - 2.5) = \frac{123}{6} + 20 = 20.5 + 20 = 40.5.

\]

Thus, the area is approximately 40.5 square units.

Velocity and Position Analysis

The velocity function is \(v(t) = 9t^2 + 4t\). To find the position function \(s(t)\), we integrate the velocity:

\[

s(t) = \int v(t) dt = \int (9t^2 + 4t) dt = 3 t^3 + 2 t^2 + C.

\]

Given initial position \(s(0) = 0\), we find \(C = 0\). Therefore, the position function is:

\[

s(t) = 3 t^3 + 2 t^2.

\]

At \(t=2\):

\[

s(2) = 3 \times 8 + 2 \times 4 = 24 + 8 = 32 \text{ feet}.

\]

The change in position between \(t=5\) and \(t=10\):

\[

\Delta s = s(10) - s(5) = (3 \times 1000 + 2 \times 100) - (3 \times 125 + 2 \times 25) = (3000 + 200) - (375 + 50) = 3200 - 425 = 2775 \text{ feet}.

\]

This indicates the object travels an additional 2775 feet between 5 and 10 seconds.

Modeling Population Growth

The growth rate function \(r(t) = 200 \times 1.075^t\) models the rate of change of the population over time, in thousands of people per year. To find the population \(P(t)\):

\[

P(t) = P_0 + \int_{0}^{t} r(u) du,

\]

where \(P_0 = 75,000\). The integral:

\[

\int 200 \times 1.075^u du = 200 \times \int 1.075^u du.

\]

Using the fact that \(\int a^u du = \frac{a^u}{\ln a}\):

\[

\int 1.075^u du = \frac{1.075^u}{\ln 1.075},

\]

so,

\[

P(t) = 75,000 + \frac{200}{\ln 1.075} (1.075^t - 1).

\]

Calculating \(\ln 1.075 \approx 0.072\), the population function becomes:

\[

P(t) = 75,000 + \frac{200}{0.072} (1.075^t - 1) \approx 75,000 + 2777.78 (1.075^t - 1).

\]

For selected years \(t=5, 10, 15\), the population estimates are:

- At \(t=5\):

\[

P(5) \approx 75,000 + 2777.78 (1.075^5 - 1) \approx 75,000 + 2777.78 (1.44 - 1) \approx 75,000 + 2777.78 \times 0.44 \approx 75,000 + 1222.23 \approx 76,222.

\]

- At \(t=10\):

\[

P(10) \approx 75,000 + 2777.78 (1.075^{10} - 1) \approx 75,000 + 2777.78 (2.07 - 1) \approx 75,000 + 2777.78 \times 1.07 \approx 75,000 + 2972. \approx 77,972.

\]

- At \(t=15\):

\[

P(15) \approx 75,000 + 2777.78 (3.14 - 1) \approx 75,000 + 2777.78 \times 2.14 \approx 75,000 + 5944. \approx 80,944.

\]

The integral \(\int 200 \times 1.075^t dt\) signifies the accumulated total change in the population over time, reflecting the cumulative effect of growth rate—a fundamental concept in demographic modeling.

Conclusion

This analysis underscores the versatility of calculus in solving diverse practical problems, such as computing areas, analyzing motion, and modeling population dynamics. Mastery of integration techniques allows for precise calculation and meaningful interpretation of real-world phenomena, fostering deeper understanding in fields like physics, economics, and environmental sciences.

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