# Should I do all question

1. Feb 22, 2015

### gimak

Hi everyone,

I'm studying E&M using Purcell & Morin's textbook. The end of chapter exercises are divided into problems (has detailed solutions) and exercises (no solutions whatsoever). I know I should do all the problems, but is ti worth it doing the exercises. I mean, if I try the problem, I'll never know if I have the right solution, so are the exercises worth doing?

2. Feb 22, 2015

### Niflheim

I would do at least a couple exercises, depending on the specific topic and how proficient you are at it. I would say do the problems, and check your answers. See how many you get wrong, and look over the solutions and figure out where you went wrong. Do about as many exercises as problems you got wrong, and increase or decrease depending on how well you do with it and the specific lesson covered.

3. Feb 22, 2015

### gimak

So you're saying that I should do the exercises that deal with the same subject as the problems I was struggling with. But, how do I know if I' got them right? There's 33 problems (with soln) and 50 exercises (w/o soln).

4. Feb 22, 2015

### Niflheim

Maybe I'm misunderstanding this, but if the problems have solutions can't you check your answers? And also, 33 problems is more than I was expecting, though the general thing I suggested should still work.

5. Feb 22, 2015

### gimak

The end of the chapter things are divided into 2 sections:

1) Problems-these have detailed solutions

2) Exercises-these have no solutions whatsoever

this helps?

The main question I have is if it's worth doing the exercises (#2 above). Since they don't have the answers in the back, is it worth doing? I'll never know if my answers are right.

6. Feb 23, 2015

### Staff: Mentor

In real-life problems, e.g. when you're doing research, you don't have "answers in the back of the book."

Look for alternate solution methods to provide a check on your calculations.

7. Feb 23, 2015

### symbolipoint

Check your solution in the equations you obtained or derived to find if they work.

8. Feb 23, 2015

### gimak

But since you don't have the right answer, you don't know if the equations you derived are right. So, how can you know if you have the right approach to begin with?

9. Feb 23, 2015

### Choppy

The point of an "exercise" - a problem that doesn't come with a solution that can easily be looked up in the back of the book, is that it's an opportunity to practice using what you've learned thus far. You can use them as you feel you get something out of them.

Generally these are included in a textbook for the professors to give as homework assignments.

10. Feb 23, 2015

### symbolipoint

You will observe that many textbooks have a section in the back for answers to the odd numbered problems, but the even numbered problem answers are not listed. Same idea.