Why are even numbered problems excluded from textbook answer keys?

[Alpharup]

Our University prescribes Modern physics by Arthur Beiser for learning relativity. There are many tough(for me:shy:) problems in the book.I usually solve problems from other books tone such problem had the number 52. I had tried to solve it and it took me 2 hours to solve. I had to make many assumptions. To check whether my solutions and assmptions were right, I looked at the back of the book for answers. To my surprise, I found that even number problems' answers were not included and only odd problems' answers were present. . I got very much frustrated and threw the book... Even numbered problems are much tougher and there were no solution for those...This just hinders learning according to me. To check whether my conceptual understanding was right, I need answers. When I work hard to solve and can't find the right guidance, it is frustrating.

I don't know why even number problems' answers are not printed. Could someone explain me why?

 

[HayleySarg]

I got very much frustrated and threw the book...

What did that poor textbook due to deserve that? Does picking on innocent textbooks excite you or make you feel powerful? Huh? ;)

I always assumed that even answers weren't included such that professors could ensure that students weren't just copying down solutions (as if it wouldn't become obvious on the test).

I take those problems that are very hard and stalk my professors office hours. Or a friend in the course, or a tutor if applicable. But only after I spend a decent amount of time on them.

The biggest part of learning to do physics is solving problems. And to learn to solve problems, we have to learn to accept the struggle of it all. Trust me, it's not supposed to be easy or it wouldn't be a problem to solve but rather a set of steps to do. And that's not fun!

And to add, regarding your title: "Word done is a waste"

It absolutely is not. When you have the opportunity t work through it with a professor or another student, using your work (if it's incorrect) you can identity the areas you are struggling with or are making mistakes. Work is usually not a waste, especially if something can be learned from it.

 

[jtbell]

I don't know why even number problems' answers are not printed. Could someone explain me why?

In the US at least, professors often assign problems from the book as homework. Students turn in their solutions, the professor grades them, and includes them as part of the course grade. Therefore textbooks published in the US often provide answers only for odd-numbered problems, so students can do those as "practice problems", and professors can assign even-numbered ones for grading.

In many other countries, grades are based only on exams, and students are expected to do textbook problems on their own, purely as a way of improving their understanding, and preparing for exams.

 

[jedishrfu]

There is a little known secret that if you solve problems 51 and 53 then 52 will be easier to solve. Sometimes you have to extend out to 49 and 55 but you get the idea.

Your textbook is only the messenger but knowing that don't throw it at the prof unless he doesn't know who you are. :-)

 

[dlgoff]

To check whether my conceptual understanding was right, I need answers.

Well, you'll know when it's graded. And this isn't necessarily a bad thing.

 

[Alpharup]

Hey, it was not a waste actually. Though I couldn't figure out whether my method was right, I got the highest mark in the exam. I had to really work hard in understanding special relativity and it paid off. I thought myself as inferior to others as it took a lot of time and reference books to understand the concepts. I predicted a mark of 20 out of 50(as I was uncertain about answers and method) but luckily got 40.

Moral of the story; Work done will not be waste

 

[SteamKing]

Yes, it has been a common practice for many years for textbooks (in the US at least) to print the answers for only even numbered problems or only odd numbered problems.