UPPER MATH105 2020 February All Weeks Discussions Latest

MATH105 College Mathematics/Applications

Week 1 Discussion

Student Introduction

This week's discussion is two-fold.  First, I would like you to introduce yourselves, describe your major area of your study, and where you live.

The second part of this discussion gives you an opportunity to become familiar with using the online calculator.

A)  To get started, first view this video: Online Calculator

What are some of the features that you find most helpful, or different from your usual calculator?

B)  Now watch this video:

I want you to pay specific attention to the information on using variables, presented during minutes 1:22 through 1:54.  Using this method to evaluate an expression will be extremely helpful through the course.

I would like you to try a problem using the online calculator:

Assign two variables: x = 1 and y = 2x3 – 7.6 x2 + 0.25x - 9

You should see the result  y = -14.35

If you do not get this result, you have an error in the equation.  Edit your equation to get the correct result.

Now find the value of y for x = -5

Take a screen shot and share it in the discussion.

 

MATH105 College Mathematics/Applications

Week 2 Discussion

Suppose a refrigerator that sells for $700 costs $85 a year for electricity.  Write an expression for the cost to buy and run the refrigerator for x years.

Suppose another refrigerator sells for $1000 and costs $25 a year for electricity.  Write an expression for the total cost for this refrigerator over x years.

Over 10 years, which refrigerator costs the most?  By how much?

In how many years will the total costs for the two refrigerators be equal?

 

MATH105 College Mathematics/Applications

Week 3 Discussion

How many students would demand a cell phone that costs $3,995? That was the price of the first cell phone available to the public, the DynaTAC8000X, in 1983. By 2011, the average price of a smartphone was $135, and more people were buying cell phones (EconEdLink.org).

Complete the following table to indicate how much you would be willing to pay for a cellphone by Wednesday. Indicate each and every price at which you are willing to pay for a phone. So, if you are willing to pay $500, does that mean you would pay $400, or $300, etc. Maybe not, maybe you would be suspicious of a "cheap" phone and not buy it? You will explicitly answer for each value to be clear. Just a "yes" or "no" answer is sufficient to generate the necessary data. No details as to why you would or would not choose a phone at a given price is required.

After everyone has posted on Wednesday, make a table and count the total number of students who would purchase the cellphones at each of the prices listed below.  Graph the relationship between cost and demand. Compare to Examples 3 and 4 on pages 89 to 90 of the textbook and other relevant areas. For the second part, to be clear, the requirement is to make a graph, not a table. Consider Figure 2.31 on page 88 from Example 1. Plotting the points that way is sufficient. Please add your graph to your own original post.

Relationship between cost and demand

Cost of cell phone           Would you purchase a cell phone at this price?

100      

200      

300      

400      

500      

600      

700      

800      

900      

1000    

1100    

For the cell phone data and Desmos, a scatter plot as documented here may be best.

That being said, there is no requirement to use Desmos to make this graph. Making a bar chard in Excel is also acceptable.

You could also just draw the graph by hand on paper and post a picture of it.

 

MATH105 College Mathematics/Applications

Week 4 Discussion

Find an example of a parabolic arch.  Note the height and width.  Write an equation of the quadratic function that describes your model of the arch.

 

 

MATH105 College Mathematics/Applications

Week 5 Discussion

If you had 20 rabbits.  After six months the number of rabbits had increased to 100. If the number of rabbits increased exponentially, then how many rabbits will you have at the end of one year?  Show and explain the mathematics you used to find your answer. What does it mean to increase exponentially?

Sec. 4.2 Homework Questions 4 and 5 are similar to this problem and the "Question Help" for those problems can help here.

 

MATH105 College Mathematics/Applications

Week 6 Discussion

Logarithmic models are used in lots of applications.  The loudness of sound is measured in units called decibels (dB). This is actually a measure of intensity, which relates to how much energy the pressure wave has. Decibels are a relative measurement. They relate the intensity of a pressure wave to a normal or standard pressure. The equation for determining decibels is given by the formula,

D(i)=10*log(i / i0)

In this discussion I want you to think about the loudness sound that you experience in your environment.  List the equation for determining decibels and report on the loudness of sound in decibels that you experienced. I recommend looking closely at Section 4.4 in the textbook, particularly exercise #75 on page 217. It lists enough examples for you to pick one.

Question 37 of the Sec. 4.4 Homework may also here here as it is a similar problem.

 

MATH105 College Mathematics/Applications

Week 7 Discussion

Determine the best interest rate for a new car purchase for a 48-month loan at a bank near you. $25,999 is the total including the vehicle, taxes, etc. If you finance the $25,999 with such a loan, determine the payment and the total interest paid over the course of the loan. 

Also, determine the best interest rate for a new car purchase for a 48-month loan at a credit union near year.  Determine the monthly payment and the total interest paid if the same auto loan is financed through the credit union. 

Is it true that the credit union would save you money?

 

MATH105 College Mathematics/Applications

Week 8 Discussion

I want you to think back to all of the concepts that you learned in this course.  Discuss as many of the concepts that you learned as you can.