## Tuesday, June 30, 2015

### Links to triangle classification with angles

Other problems are included, but you can find problems like the homework due on 1 July 2015 on these pages.

6x + 5y = 18
2x - y = -4

3x + 7y = 12
2x + 5y = -18

### 100 coin (or ticket) problems

a) 100 coins, all quarters and pennies, total = \$13.72

b) 100 tickets, all children (\$6) and adult (\$12), total =\$912

c) 100 coins, all quarters and nickels, total = \$8.20

d) 100 coins, all dimes and pennies, total = \$3.79

e) 100 coins, all dimes and nickels, total = \$7.85

f) 100 coins, all quarters and dimes, total = \$14.65

## Sunday, June 28, 2015

### The Richter scale: From two readings, the relative strength and vice versa

In class last week, we learned how to find out how much stronger one quake is compared to another given the two Richter scale readings. For example, on June 28, the strongest quake in the U.S. was a 3.4 in Oklahoma, while the strongest in North America was a 5.4 in Niltepec, Mexico. What is the difference in levels of energy? Here are the steps.

Step 1: Subtract little from big. In our case, 5.4 - 3.4 = 2.0.
Step 2: multiply difference by 1.5. 2.0 * 1.5 = 3.0.
Step 3: Raise 10 to the power of the answer from Step 2: 10^3.0 = 1,000. The Mexican quake was 1,000 times stronger than the Oklahoma quake.

Let's ask the question in the opposite direction. Let's say we have a reading for a quake and we know another quake was x times stronger. Again, it will be a three step process, but now we will take the inverse of our three steps above in reverse order. Let's say we have a quake 350 times stronger than the one in Niltepec.  Here are our steps.

Step 1: Take the log of the strength multiplier. Log is the inverse of raising 10 to a power, just like addition is the inverse of subtraction and division is the inverse of multiplication. log(350) = 2.544...,
Step 2: divide the answer from Step 1 by 1.5 and round this answer to the nearest tenth. 2.544/1.5 = 1.696..., which rounds to 1.7. We round to the nearest tenth because the Richter scale rounds to the nearest tenth.
Step 3: Add the answer from Step 2 to the Richter reading we know. In this case, it would be 5.4+1.7 = 7.1, the reading of the stronger quake. If instead we were told a quake was 350 times weaker than Niltepec, it would be 5.4-1.7 = 3.7

1. 16 times stronger than a 6.1
2. 250 times stronger than a 6.7
3. 8 times weaker than a 5.8

## Wednesday, June 24, 2015

### Link to the computer science biographies

Click on this link for the biographies of the five computer scientists. There will be questions on them on the midterm tomorrow.

## Tuesday, June 16, 2015

### Links to homework 1, due Wednesday 17 June 2015

Link for prime factorization and all factors, with practice examples.

Roman and Hindu-Arabic numerals, fractions and decimals.

Practice for Roman to Hindu-Arabic and vice versa, fractions and decimals.

Practice for time conversion.

The following problems are in the form minutes:seconds. If the answer gives more than 60 minutes, write the answer as hours:minutes:seconds. Answers to the question below are in the comments.

18:34
- 6:58

42:23
41:07
43:01
42:18
+42:17

## Friday, June 12, 2015

### Syllabus for Summer 2015

Math 15: Math for Liberal Arts Summer 2015 (L1 30451)
Instructor: Matthew Hubbard
Email: mhubbard@peralta.edu
Text: no required text. If you want a text, personal recommendations can be made
Class website: http://mathlibarts.blogspot.com/
Class hours MTWTh: 10:00 am - 12:05 pm, G-211
Office hours: Math lab G-201
TTh 9:25-9:55 am 3:05-3:35 pm (also available by appointment)
Scientific calculator required (TI-30IIXs, TI-83 or TI-84 recommended)

Last date to add, if class is not full: Sat., June 21
Last date to drop class without a "W": Sat. June 21
Last date to withdraw from class: Tues., July 23

Holidays: No holidays this session

Midterm and Finals schedule:

Midterm 1__________Thursday, June 25
Midterm 2__________Thursday, July 9
Comprehensive Final ___Thursday, July 23

Quiz schedule (most Tuesdays and Thursdays) no make-up quizzes given
First week: 6/16 and 6/18
Second week: 6/23
Third week: 6/30 and 7/2
Fourth week: 7/7
Fifth week: 7/14 and 7/16
Sixth week: 7/21

Homework to be turned in: Assigned every Tuesday and Thursday, due the next class
(late homework accepted at the beginning of next class period, 2 points off grade)
If arranged at least a week in advance, make-up midterm can be given.

The lowest two scores from homework and the lowest two scores from quizzes will be removed from consideration before grading.

Quizzes 25%* best 2 out of three of these grades
Midterm 1 25%* best 2 out of three of these grades
Midterm 2 25%* best 2 out of three of these grades
Homework 20%
Lab 5%
Final 25%

Anyone who misses less than two homework assignments and gets a higher percentage score on the final than the weighted average of all grades combined will get the final percentage instead deciding the final grade.

Anyone with a class grade of 97% out of all work before the final (this grade will be given on the next to last day) does not have to take the final. That grade is worth an A.

Academic honesty: Your homework, exams and quizzes must be your own work. Anyone caught cheating on these assignments will be punished, where the punishment can be as severe as failing the class or being put on college wide academic probation. Working together on homework assignments is allowed, but the work you turn in must be your own, and you are responsible for checking its accuracy. If I see multiple homework assignments turned in with the exact same wrong answers, I will give a warning. If it happens a second time, the student will get a 0 on the assignment and it will be counted towards the grade.

Class rules: Cell phones and beepers turned off, no headphones or text messaging during class
You will need your own calculator and handout sheets for tests and quizzes. Do not expect to be able to borrow these from someone else.

Student Learning Outcomes

• Analyze an argument for validity using simple rules of logic, and if invalid identify the type of mistake made.
• Compute, with sophisticated formulas, such quantities as interest payments for amortized loans.
• Interpret patterns and draw inferences from them.

Students with disabilities
The Disabled Students Program Services (DSPS) should have your academic accommodation with the instructor. After the first day, I will accept these accommodations electronically or by hard copy on paper. If you need academic accommodation and have not yet applied, please call 510-464-3428 for an appointment.

Exam policies
Quizzes will be closed book and closed notes. Some information you will be expected to remember, other formulas and information will be provided. No sharing of calculators is allowed. You are responsible for knowing how to use your calculator to find answers.

The reciprocal relationship

The teacher will be on time and prepared to teach the class.
The students will be on time and prepared to learn.

The teacher will present the material to the best of his ability.
The students will absorb the material to the best of their ability. They will ask questions when topics are not clear.

The teacher will do his best to answer the questions the students ask about the material, either by repeating an answer with more details included or by taking a different approach to the material that might be clearer to some students.
The students will understand if the teacher feels a topic has been covered enough for the majority of the class and will accept questions being answered outside the class, either in extra time or through written communication.

The teacher will do his best to keep the class about the material. Personal details and distractions that are not germane to the class should not be part of the class.
The students will do their best to keep the class about the material. Questions that are not about the topic should be avoided. Distractions like cell phones and texting are not welcome when the class is in session.

The teacher will give assignments that will help the students master the skills required to pass the course.
The students will put in their best efforts to complete the assignments.
When the assignments are completed, the teacher will make every effort to get the assignments graded and back to the students in a timely manner, by the next class session whenever possible.

The teacher will present real life situations where the skills being learned will be used when they exist. In math, sometimes a particular skill is needed in general to solve later problems that will have real life applications. Other skills have the application of “learning how to learn”, of committing an idea to memory so that committing other ideas to memory becomes easier in the long run.

The student has the right to ask “When will I use this?” when dealing with mathematical topics. Sometimes, the answer is “We need this skill for the next skill we will learn.” Other times, the answer is “We are learning how to learn.” Both of these answers are as valid in their way as “We will need this to understand perspective” or “We use this to balance our checkbooks” or “Ratios can be used to figure out costs” or other real life applications.