# Foerster's Alg 2 Solutions--wrong?

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1. The easy question: Is there an errata page for Foerster's Alg 2/Trig Solutions Manual? I've googled & come up w/ nothing, but those pages always seem really tricky to find. :P

2. If there's not--have you guys noticed any errors in the solutions manual? We're dealing w/ a really simple problem in ch 3, & I'm convinced that ds is correct, but if he is, then that one lesson has at least 2 errors in the SM. And you know, that seems statistically unlikely. So...?

I don't want to have this much trouble when we're only on ch3! *blush*

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Would you care to paste the problem and his answer?

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I have never noticed any errors. We don't do every problem. Why don't you post the question and people can post the correct answer.

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Exercise 3-2, problems 3 & 5:

3. y=(-3/2)x-4

5. y=2x-5

I'll see if I can take a pic of the answer w/ my phone, since it's a graph. Basically--he's starting at--for ex, problem 3, (0,-4). The SM does the same. Then it seems to be a simple rise over run--over 2, down 3, etc. This is where the book is different on both of these problems (but not the rest in the lesson)--it goes over 2, down FOUR.

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For problem 3,

Slope is rise/run = -3/2 over 2 down 3

Passing through (0,-4) and (2,-7)

For problem 5

Slope = 2

Pass through (0,-5) and (1,-3)

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So I took pics. I found a button to "compress" them for web pages, which worked for changing my avatar earlier today, but they still won't upload. I put the pics along w/ an explanation of the problem on my blog as well as links that make ds's work look Really Really Right to me. But I'd find so much assurance in an errata page. Kwim?

http://aubreylively.blogspot.com/2014/08/algebra-2-solutions-manual-vs.html

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I put the pics along w/ an explanation of the problem on my blog as well as links that make ds's work look Really Really Right to me.

An easy way to check your worked solution of straight line graphing questions is to take any two points on the line and substitute back to the original equation.

The solution for prob 5 from the solution manual posted on your blog is wrong because (2,0) is not a valid point for y = 2x - 5

Can't tell for prob 3 because the y co-ordinate isn't labeled for x = 2

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For problem 3,

Slope is rise/run = -3/2 over 2 down 3

Passing through (0,-4) and (2,-7)

For problem 5

Slope = 2

Pass through (0,-5) and (1,-3)

Yep, that's what ds put. And the Google grapher did the same. And I did, too, but I took Alg 2 through ACE, lol, so I hesitate to jump right to THE BOOK IS WRONG. TWICE. IN ONE LESSON. Oh well. Let's move on! LOL

The last lesson we had trouble w/ was yesterday. It asked for "reasonable graphs" for about 20 problems. The SM said, "These are some reasonable graphs. Maybe yours are even more reasonable!" :D Except. None of ds's matched the book. Now, I understand that they don't have to, but whereas for Geometry I was able to generally understand where the proofs had some leeway...well, good grief. HOW AM I SUPPOSED TO DO THIS? IF I CAN'T EVEN KNOW GENERALLY if he's right or wrong.

I was freaking out yesterday, so I made him sit down & do a BUNCH of math, so I could know for sure whether or not I'd be able to teach it. Because if not? He can go down to the local high school for just this one class & take it there, & they were super friendly on the phone. But there's a soft deadline of tomorrow at noon--basically, they just don't want him to get behind, & I agree. IF he needs to go there for math, he should do that right away.

This lesson, while it seemed very easy still, well, it's got me rattled again. I mean...I don't think I can do this w/out a reliable SM! *sigh* I feel very definitely ALL CAPS about TWO ERRORS in ONE LESSON.

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The last lesson we had trouble w/ was yesterday. It asked for "reasonable graphs" for about 20 problems. The SM said, "These are some reasonable graphs. Maybe yours are even more reasonable!" :D Except. None of ds's matched the book.

Straight line graphs have to be accurate. Quadratic, trig, log graphs are to be reasonably accurate drawn with a flexible curve/flexi-curve.

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An easy way to check straight line graphing questions is to take any two points on the line and substitute back to the original equation.

The solution for prob 5 from the solution manual posted on your blog is wrong because (2,0) is not a valid point for y = 2x - 5

Can't tell for prob 3 because the y co-ordinate isn't labeled for x = 2

Problem 3, x=2 looks like y=-8.

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Straight line graphs have to be accurate. Quadratic, trig, log graphs are to be reasonably accurate drawn with a flexible curve/flexi-curve.

Right, but these were like...the graph of a yo-yo or...ack. He never puts his book away, but tonight?

27. The rate at which you are breathing depends on how long it has been since you finished running a race.

30. The amt of postage you must put on a first class letter depends on the weight of a letter.

32. You plant an acorn. The height of the resulting oak tree depends on the number of years that have elapsed since the planting.

So if I had read the questions, I would have had a better idea of the rightness (reasonableness) of his answers, & I didn't do that until just now. But his answers...if it had height on the y axis & speed on the x, he did the opposite almost every time. I can't see why that would matter on these imagination-style problems, but I DON'T KNOW.

In the end, I had him study the graphs in the SM to see what they came up w/ & then just moved on. :P

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But his answers...if it had height on the y axis & speed on the x, he did the opposite almost every time.

For plotting of graphs, I ask my kids to follow this rule of thumb

"Use the x-axis for the independent variable (that which is experimentally varied; also known as the manipulated variable) and the y-axis for the dependent variable (that which is a function of the independent variable; also known as the responding variable)." (Link http://chemlabs.uoregon.edu/GeneralResources/graphing.html)

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I pulled out my books and the answer key is wrong for the first 2 you posted. I have never used the key for those problems. But I looked at the key for the other problems you psetrd and the key is correct.

For example, breathing rate decreases over time but reaches an asymptote bc you never stop breathing, postage is flats within a weight range, and tree growth is more rapid initially and the rate decreases with time.

It does matter bc he is inverting the independent and dependent variables if I understand your post correctly.

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School text book publishers never seem to put errata out.  In the Software Development world - errata are published and the author usually apologizes even when it is probably the editors fault.

For popular home school texts folks should collect errata and share.

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Thank you so much, guys. I've just been so nervous about teaching this level--partly because Geometry was MUCH harder (for me) than I'd expected it to be. I've been doing a lot of second-guessing. I think this experience has given me the confidence to keep googling when I'm not certain about the SM & the other things I did. (Have ds explain his answer, do some others to make sure he's got the concept, etc.)

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• 1 month later...

I just joined this forum to respond to this post.  I am using foerster Algebra and Trigonometry in a co-op class. And the solution manual is a disaster! A diligent student has already found 9 errors in the first 26 pages.  I am trying to find an errata list as well.

Today I heard from one of my algebra I students that they have found lots of errors in the Foerster Algebra I solutions book also.

This is so frustrating to students, parents and me the teacher!!!

The Foerster textbooks are excellent.  I have used them for years.  But the solutions are a disaster!

I'll try to get a list posted at some point but this is very time-consuming trying to figure out.

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Are the selected answers given in the back of Algebra and Trigonometry correct?

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I just joined this forum to respond to this post.  I am using foerster Algebra and Trigonometry in a co-op class. And the solution manual is a disaster! A diligent student has already found 9 errors in the first 26 pages.  I am trying to find an errata list as well.

Today I heard from one of my algebra I students that they have found lots of errors in the Foerster Algebra I solutions book also.

This is so frustrating to students, parents and me the teacher!!!

The Foerster textbooks are excellent.  I have used them for years.  But the solutions are a disaster!

I'll try to get a list posted at some point but this is very time-consuming trying to figure out.

ask here as well:

https://groups.yahoo.com/neo/groups/MathWithoutBorders/conversations/topics

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