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### Lecture 4: The design recipeðŸ”—

This assignment is due on Tuesday, September 3 at 11:59pm. Submit it using Handin as assignment lecture4. Your submission is only accepted if the message “Handin successful” appears.

#### 1The origin of parenthesesðŸ”—

Exercise 1. Put the missing closing parenthesis in the right place:
 (place-image (scale 2 bicycle horizontal-position 150 (empty-scene 300 300))
Put the fixed expression in a comment.

Exercise 2. Answer each problem below with one arithmetic formula. Indent each formula properly.
1. At the market, I bought an apple for \$1 and a sandwich for \$5. What is the total that I spent? The answer to this problem is (+ 1 5), so put this in your Definitions Window:
 (define part1 (+ 1 5))

2. At the market, I bought an apple for \$1 and a sandwich for \$5. Because a sandwich is a prepared food item, it is taxed 7%. What is the total that I spent? Define a constant named part2 with your formula.

3. At the market, I bought a baked apple for \$1 and a sandwich for \$5. Because both are prepared food items, both are taxed 7%. What is the total that I spent? Define a constant named part3 with your formula.

4. At the restaurant, I ordered a baked apple for \$1 and a sandwich for \$5. Both are taxed 7%, and I also decided to pay 20% tip on the amount before tax was added. The tip is not taxed. What is the total that I spent? Define a constant named part4 with your formula.

5. At the restaurant, I ordered a baked apple for \$1 and a sandwich for \$5. Both are taxed 7%, and I also decided to pay 20% tip on the amount after tax was added. What is the total that I spent? Define a constant named part5 with your formula.

6. Like the last probem, but what if I rounded up the final amount to the nearest dollar (using the ceiling function)? Define a constant named part6 with your formula.

#### 2Designing a function with 1 inputðŸ”—

Exercise 3. Design a function named ctok that converts a temperature in Celsius to a temperature in Kelvin. Start by copying the following list of steps into your Definitions Window:
 ; Exercise 3 ; 1. Data definitions ; 2. Signature, purpose, header ; 3. Function examples ; 4. Function template ; 5. Function definition ; 6. Testing

Submit your work using Handin as assignment lecture4. Be sure to submit on time. Submit early and submit often, any number of times until the deadline!

Important Note Whenever you write a function in this class, you need to follow the design recipe.

Exercise 4. Turn all your function examples from comments into automatic tests.

Keep submitting your work any number of times until the deadline. Be sure to submit on time. Watch out for submitting to the wrong assignment.

#### 3Designing a function with 2 inputsðŸ”—

Exercise 5. Design a function named coins that takes as inputs how many nickels and how many dimes I have and calculates how many dollars I have in those coins. Hint: If you need to review how to write a template, you can watch this additional video.