# Search results

1. ### Thermo Concept Questions

Homework Statement Hey, I was wondering if I could get some help verifying my answers for these general thermodynamics concept questions. Thanks! 1. A reversible reaction is at equilibrium at constant pressure and temperature if the free energy of the system ______________. 2. Heat...
2. ### Basic limit involving absolute value

Im still not seeing the big picture here. Can you write out exactly what this problem should look like with all the steps at least partially worked out?
3. ### Basic limit involving absolute value

Ok, I see what you are saying now, but when I graphed the parabola, I also saw that coming from the right-hand side, the values of x were also positive up until x=1.
4. ### Basic limit involving absolute value

Im still not sure how it is you are coming to the statement that "if x comes from the left, then this expression is positive." Can you explain how you are getting this? Here is what I have now:

6. ### Basic limit involving absolute value

I do not see how they should be switched. Can you explain your process in more detail?
7. ### Basic limit involving absolute value

Ok, from the left-hand side of the limit, I got -2, and from the right-hand side I got 2, and when x-1=0 I got "does not exist." Is this right?
8. ### Basic limit involving absolute value

Homework Statement lim as x\rightarrow-1 = \frac{|x^{2}-1|}{x^{2}+x} Homework Equations N/a The Attempt at a Solution Tried to write this as a piecewise function, but I got lost.
9. ### Integration by parts & inv. trig fxn

Oh, ok. Thanks again!
10. ### Integration by parts & inv. trig fxn

I still dont see how this gets (1/8), and even then, what is the purpose of doing this, and where does the (2x) come from?
11. ### Integration by parts & inv. trig fxn

Homework Statement \int xarcsin2xdx 2. The attempt at a solution Can someone explain to me what is happening at step 2? I understand how the integration by parts was done, but where does the (1/8) or (2x) come from?
12. ### Applying Integration by Parts & Trig Substitution

Okay, I got it now. Thanks for all your help!
13. ### Applying Integration by Parts & Trig Substitution

Okay, thats what I thought you wanted me to do. I am now left with this: (7/4)\int sec^{3}Θ = (3/4)secΘtanΘ - (3/4)ln\left|secΘ + tanΘ\right| + C Now I need to manipulate the fraction so as to get (4/3)\int sec^{3}Θ How do I do this?
14. ### Applying Integration by Parts & Trig Substitution

I am still not seeing it. Currently, I have \int sec^{3}Θ = (3/4)(secΘtanΘ - \int tan^{2}ΘsecΘ)
15. ### Applying Integration by Parts & Trig Substitution

Is there anyone that can help me finish this problem?
16. ### Applying Integration by Parts & Trig Substitution

Alright, I still seem to have a problem. I now have (3/4)(secθtanθ)-\int tan^{2}θsecθ Where do I go from here?
17. ### Applying Integration by Parts & Trig Substitution

Wow, I can't believe I missed this! Thank you!
18. ### Applying Integration by Parts & Trig Substitution

How do I integrate dv? I know the integral of sec θ = ln ( sec θ + tan θ) + c But what about sec2?
19. ### Applying Integration by Parts & Trig Substitution

Homework Statement \int\sqrt{4+9x^{2}}dx Homework Equations Pythagorean Identities? The Attempt at a Solution I find it sort of cumbersome to use the special formatting here, so I hope it is okay that I just photocopied my work on paper. You can see how far I made it, but...
20. ### Integrating a fxn with f(x^2)

Wow, I cant believe I didnt try u-sub first! My final answer came to be \frac{f(b^{2})-f(a^{2})}{2} Thanks!
21. ### Integrating a fxn with f(x^2)

Homework Statement http://img857.imageshack.us/i/no34.jpg/ [Broken] Homework Equations The Fundamental Theorem of Calculus, i.e., taking the derivative of an integral yields the original function. The Attempt at a Solution I am not sure how to go about integrating this function...
22. ### Evaluating point using derivative graph

Okay, thanks for your help guys! I really appreciate it!
23. ### Evaluating point using derivative graph

Oh, I was unaware of the equivalent form. This makes much more sense now! One last question though. One of the theorems states that the derivative of an integral is the original function. Does this statement also work in reverse? I.e. the integral of a derivative also yields the original...
24. ### Evaluating point using derivative graph

Homework Statement *note that this is the graph of the derivitive of the function f(x). Homework Equations Possibly the fundamental theorems of calculus? The Attempt at a Solution I know this problem should be easy, but I am not seeing how my book comes to the answer. Below is the...
25. ### How many combinations?

Originally, I had thought this too, however, I think the order matters here, so the permutation formula must be used.
26. ### How many combinations?

Ok, so I should use n!/(n-r)! so, 6!/(6-4)! = 360?
27. ### How many combinations?

I dont have a textbook, but im thinking permutations. I dont really know how they differ functionally from a combination though.
28. ### How many combinations?

I would think the order is important, but how does that help me?
29. ### How many combinations?

This implies that after each time I have chosen a letter, there is one less to choose from. I tried to use n! to find an answer by doing 6x5x4x3x2x1, but the resulting answer was way to large.
30. ### How many combinations?

Im not sure how this is so easy for you. I assume that the question means that no lettter can be used more than once within one of the 4-letter codes. If this is the case, then there are way to many codes to write by hand. This problem came from a review worksheet. If this is not a...