Hands-on Day: Scripts

Hands-on Day

Scripts

Note: All of these problems are for practice. You are freely encouraged to work together and you do not need to submit any of this work for a grade.

Write a program that asks a user for their favorite fruit, and then prints a response as follows:
What is your favorite fruit? apple I like apples too.
For the sake of simplicty, assume that you may simple add an 's' to the end of the response to make it plural.

Answer:
```
   fruit = input('What is your favorite fruit? ')
   print('I like ' + fruit + 's too.')
```

Write a program that asks the user to enter a temperature in Fahrenheit and reports the equivalent temperature in Celsius. You may use the formula $c = \frac{5}{9}(f - 32)$ for doing the conversion. A sample session might appear as follows:

Enter a temperature in Fahrenheit:  85
85 Fahrenheit is equivalent to 29.4444 Celsius.

Answer:

   fahr = float(input('Enter a temperature in Fahrenheit: '))
   celsius = 5 * (fahr - 32.0) / 9
   print(fahr, 'Fahrenheit is equivalent to', celsius,
   'Celsius.')

Write a program that prompts the user for the radius of a circle, and which reports both the circumference and the area of that circle. As a reminder the circumference would be $2\pi r$ and the area would be $\pi r^2$. A sample session might appear as follows:

What is the radius of your circle? 5
A circle of radius 5 has circumference 31.4159
and area 78.53975.

Answer:

   r = float(input('What is the radius of your circle? '))
   circ = 3.14159 * 2 * r
   area = 3.14159 * r * r
   print('A circle of radius', r, 'has circumference', circ)
   print('and area', str(area) + '.')

There is a classic story (maybe it's even true) about mathematician Carl Gauss as a child. The story isthat a teacher, wanting to keep him busy for a long time, asked Gauss to compute the sumof the numbers from 1 to 100. Though the teacher presumed he would need to take time to repeatedly add one number at a time to the total, he returned quickly with the correct answer, answer, having effectively derived that the sum of the first $n$ numbers equals $\frac{n(n+1)}{2}$.

Though we will eventually learn to use loops in Python to automate repetitive tasks, we can follow Gauss's lead for now, to compute the sum of the first $n$ number without loops. Write a program that produces an interaction as follows.
Please enter a value for n: 100 The sum of the first 100 numbers is 5050.
Answer:
```
   n = int(input('Please enter a value for n: '))
   total = n*(n+1) // 2                                             #
   integer division
   print('The sum of the first', n, 'numbers is',
   str(total)+'.')
```

Write a program that prompts the user for the length of the hypotenuse of a right triangle, and for the length of on of its legs, and which computes and outputs the length of the second leg. A sample session might appear as follows:

Let's discuss a right triangle.
What is the length of the hypotenuse? 5
What is the length of one of the legs? 4
The length of the other leg is 3.0.

Answer:

   print("Let's discuss a right triangle.")      # doublequote as
string delimeter
   c = float(input('What is the length of the hypotenuse? '))
   a = float(input('What is the length of one of the legs? '))
   b = (c**2 - a**2) ** 0.5
   print('The length of the other leg is', str(b) + '.')

While a person's pulse is generally reported in beats per minute, technicians rarely monitor for a full minute, but instead extrapolate after observing a shorter time. For example, if there were 20 beats in 15 seconds, then the pulse is 80 beats per minute.

Write a program that assists with this calculation, after receiving input about the user's observations. Presume that the pulse should be reported as a (truncated) whole number. A sample session might appear as follows:
How many beats were observed? 20 How many seconds were observed? 18 The pulse is 66 beats per minute.
Answer:
```
   beats = int(input('How many beats were observed? '))
   secs = int(input('How many seconds were observed? '))
   pulse = 60 * beats // secs
   print('The pulse is', pulse, 'beats per minutes')
```
Write a program that computes the roots of the classic quadratic equation, $Ax^2 + Bx + C = 0$, with the user providing the constants $A$, $B$, and $C$. You may use the quadratic formula which states that the roots are $$\frac{-B + \sqrt{B^2-4AC}}{2A}, \frac{-B - \sqrt{B^2-4AC}}{2A}$$ and you may assume, for simplicity, that the roots are well-defined (although conveniently Python has support for complex roots). A sample session might appear as follows:
Solving quadratic equation A*x*x + B*x + C = 0. What is A? 2 What is B? -5 What is C? -3 One root is 3.0. The other is −0.5.
Answer:
```
   print('Solving quadratic equation A*x*x + B*x + C = 0.')
   a = float(input('What is A? '))
   b = float(input('What is B? '))
   c = float(input('What is C? '))
   det = (b*b - 4*a*c)**0.5
   root1 = (-b + det)/(2*a)
   root2 = (-b - det)/(2*a)
   print('One root is', str(root1) + '.')
   print('The other is', str(root2) + '.')
```

Last modified: Saturday, 21 December 2019