Lecture 2 — Exercises
=====================

Overview
--------

Two sets of exercises are given below.  Problems in the first set are
for you to work on your own but not submit for a grade.  Problems in
the second set must be submitted for a grade.  Normally, these will be
due within 24 hours of the end of the lecture they are associated
with.  For these Lecture 2 exercises only, they will be due at the end
of Lab 1 so that any problems with submission can be ironed out.

Students are welcome to work on these problems in small groups, but
each student should write the final version of their solutions
independently.  Each student should submit their own solutions.

Practice Problems
-----------------

#. Write a single line of Python code that calculates the radius of a
   circle with area 15 units and prints the value.  The output should
   just be the number that your code produces.  Your code should include
   the use of an expression involving division and exponentiation (to
   compute the square root).  Use the value 3.14159 for *pi*.

#. Which of the following are legal Python variable names?

::

   import
   56abc
   abc56
   car-talk
   car_talk
   car talk

3. Which of these lines of code contain syntax errors? Once you fix
   the syntax errors, the program will still not correctly print the
   area of a circle with radius 6.5.  What two more changes are needed
   to fixed these errors?

::

     pi = 22 / 7
     area = pi * r * r
     r = 6.5
     r + 5 = r_new
     print(area)


Problems for Grade Submission
-----------------------------

#. Write a single line of Python code that converts the temperature
   64 from Celsius to Fahrenheit and prints the value.  Submit a Python
   file containing just this single line of code.  The output should
   just be the number that your code produces.  Your code must include
   the use of an expression involving multiplication and a *print*
   function call.

#. Write Python code that creates three variables called
   *length*, *width* and *height* to store the dimensions of a 16.5 x
   12.5 x 5 box.  Write additional code that calculate the volume
   of the box and calculations its surface area, storing each in a
   variable.  Print the values of these variables.  Your code must use
   five assignment statements and two print function calls.  Submit a
   file containing these seven lines of Python code. Your output
   should be

::
  
   volume = 1031.25
   area = 702.5

3. Your problem is to determine the output of the Python program shown
   below.  You must submit a text file showing the output.  (Hint:
   there should be two lines with one integer on each line.)  While it
   is possible to just run the program and copy the output, we
   *strongly* encourage you to not do this.  You will need to develop
   the ability to read code and understand what it will do.  You will
   be tested on it.

::

    z = 2
    z = z**2**3
    print(z)
    x = 6
    x = x**2 + 6 - z // 10 * 2
    print(x)