# Errata

This page lists actual math errors in the various editions. Simple typos, misspellings, and such are not listed here. Also not listed are things that were correct but simply deserved improvement.

### Spring 2017 edition (typeset on January 18, 2017)

Spring 2017 edition (typeset on January 18, 2017)

- None yet!

### Fall 2016 edition (typeset on August 30, 2016)

Fall 2016 edition (typeset on August 30, 2016)

- Section 3.6: In exercise 101, water with toxic substance is flowing into the tank with concentration 20t grams per liter at time t, not at a concentration of 20 grams per liter.

### Spring 2016 edition (typeset on January 14, 2016)

Spring 2016 edition (typeset on January 14, 2016)

- Section 1.2: The book should explain how to download and install the file qdraw.mac into a user's working folder.
- Section 3.5: In exercise 101, water with toxic substance is flowing into the tank with concentration 20t grams per liter at time t, not at a concentration of 20 grams per liter.

### Fall 2015 edition (typeset on August 29, 2015)

Fall 2015 edition (typeset on August 29, 2015)

- Section 1.2: The book should explain how to download and install the file qdraw.mac into a user's working folder.
- Section 2.5: Exercise 7 makes more sense if f(x)=1.
- Section 3.3: In exercise 14, the independent variable is time t, not outdoor temperature T. The model should therefore be dU/Dt=-k(U-T).
- Section 3.5: In exercise 101, water with toxic substance is flowing into the tank with concentration 20t grams per liter at time t, not at a concentration of 20 grams per liter.
- Section 4.1: For exercises 108 and 109, the solutions are switched.

*Updated 18 January 2018.*