Test 1

Create the following directories for storing your answers to today's test. Make sure all of the files you create are stored within this directory.

$ cd ~/cs120/
$ mkdir test1
$ cd test1

You are only allowed to access this course webpage, the Python and Turtle documentation webpages. You are not allowed to access any other websites. You may access any python files within your personal home directory. You are not allowed to access files of any other type, or files from any other user's directories. Failure to abide by these rules is a violation of Academic Integrity, and will be treated as such.

Question 7

Create a file called question_6.py. Put your answers to the following questions there.

(3 points each, 15 points total)

• Create two variables named current_year and birth_year. Store the current year and your birth year in the proper variables.

  Using these variables, write an expression to print your current age.

• Write a function age_in_leap_years, which takes a single parameter representing the age of the requester, and prints an estimate of how old they would be assuming they were born on Feb. 29^th. Assume that a leap year has occurred every 4 years since their birth.

  Use this function to print how old you would be if you were born on Feb. 29^th.

• Write a function compute_circle_area. This function should take one parameter, the radius of a circle. It should return the area of a circle with the specified radius.

  Recall the area of a circle can be computed using the following equation:

  $$area = \pi \times radius^{2} $$

  Using this function, print the area of a circle that has a radius equivalent to your (actual, not leap year) age you computed above.

• Using the circle method from the turtle module, draw a circle with the radius you used above centered around (0, 0).

• Write a function called circumscribe_circle, which takes three parameters: the center x coordinate, the center y coordinate, and the radius of the inscribed circle. This function should use a for loop to draw a square which circumscribes the circle that is specified in the formal parameters of the function.

  Using this function to draw a square around the circle drawn above.

Question 8

Half-lives

Radioactive materials experience radioactive decay. This results from the atoms of the material emitting particles as radiation. Over time, this radiation reduces the amount of material that is still present. A common measurement of this phenomenon is deemed "half-life." Half-lives for common materials can be found on Wikipedia.

Create a file called question_7.py that contains a function called compute_duration(material_amount, half_life). The material_amount parameter is the amount of material in grams, while the half_life parameter is the time (in seconds) that it takes for half of the material_amount to decay by half.

This function should compute (and return) the duration (in seconds) that the material will continue to exist. You can compute this value by multiplying the half-life by: $$ log_{2}\left( \frac{amount}{EPSILON} \right)$$ where EPSILON is a constant with value 0.000001. Remember that you can use the log function from the math module to compute logarithms.

In the same file, use the function you wrote to complete (by printing out) the following table.

(15 points)

Bonus

Fibonacci Sequence

The Fibonacci sequence is a famous mathematical sequence of numbers that is strongly related to the Golden Ratio. One of the wonders of the sequence is its exceedingly simple definition. Let F_n define the n^th number in the Fibonacci sequence, where F₁ = 1 and F₂ = 1. Then, the n^th number can be computed as:

Create a file called bonus_question.py. In this file, write a function called compute_fib, which takes a single parameter n, and uses a for loop to compute and ultimately return the n^th number of the Fibonacci sequence.

Submission

When you have finished, create a tar file of your test1 directory. To create a tar file, execute the following commands:

cd ~/cs120
tar czvf test1.tgz test1/

To submit your activity, go to inquire.roanoke.edu. You should see an available assignment called Test #1.