# Can I ask for someone to check a derivative?

So I did some maths and wonder if I did it correct. Is here to correct place to ask a question of the form:

I need to find the derivative $\frac{dF}{dx}$ and here is my solution. Is this correct?

As the answer would be 'yes' or 'no' (ideally with some pointers to why). Would these type of question be considered on topic?

• Sure, they are on topic: you can ask that, and one tag to use would be "proof-verification" which covers both solution-and-proof-verification questions. After posting the question and your solution and your question whether is correct, feel free to, in addition to addressing the solution's correctness, ask if there are other methods of solving the question. Feb 27, 2018 at 21:36
• IMHO, for routine stuff, you should install a CAS on your computer and compute it locally first. It is typically much faster than asking a question here (composing a "good" question takes more time than using a CAS). Even if you can compute something by hand, it is a good habit to have a CAS to double check what you get. You ask the question when you don't know how to proceed. You can use what you have tried using a CAS or paper/pencil as context. There is a lot of people here who insists on question need to have some sort of context. Feb 28, 2018 at 3:50
• @achillehui Can you please give an example of a free CAS PC software good enough for high school? (I searched but couldn't find) I was hoping you know of one. Thanks! Mar 2, 2018 at 15:18
• @GaurangTandon Some online ones are Wolfram Alpha and Mathway. One that you could install to use locally is SageMath. Just beware that the temptation is to let the computer do your homework for you, which doesn't result in learning the material. Mar 2, 2018 at 15:38
• @Teepeemm Thanks! I use WA frequently, but didn't know it comes under CAS category :P "Just beware that the temptation is to let the computer do your homework for you" Yep, I agree. Definitely. Mar 2, 2018 at 15:41
• @GaurangTandon I wouldn't call it a CAS, but it is able to find a derivative. Mar 2, 2018 at 16:14
• I think this kind a question, if you are asking it, is fine. However, a caveat. Please mention your working. I would, in fact, suggest that you write an answer to your own question in this case, because all others can do is say "yes, it is right" which they would do with a comment, or "it is wrong here : ..." and you can modify the answer when they point out the error. Or, if the error is grave, then they can write their own answer. But answering your own question allows you to close it comfortably if you happen to have done everything right. Mar 3, 2018 at 3:39
• Since you are a new user, I think it is vitally important that your question does not disappear into the deleted wilderness, which can easily happen, especially with questions which look short and PSQ-like. Writing an answer to your question is one way of ensuring this does not happen. Mar 3, 2018 at 3:45
• I think proof verifications are ideally formulated by explaining for which parts of the proof you feel uncertain. For instance did I apply the chain rule here correctly etc. If you are certain about your knowledge and only want to double check your calculations I think what achuile suggested in most cases is most sensible Mar 12, 2018 at 2:34

As suggested in the comments, at least in some situations it might be easier to let computer check your computation.

IMHO, for routine stuff, you should install a CAS on your computer and compute it locally first. It is typically much faster than asking a question here (composing a "good" question takes more time than using a CAS). Even if you can compute something by hand, it is a good habit to have a CAS to double check what you get. You ask the question when you don't know how to proceed. You can use what you have tried using a CAS or paper/pencil as context. There is a lot of people here who insists on question need to have some sort of context. -- achille hui

It might be useful to collect here some tools which are available for typical introductory calculus problems. (And maybe to some list of such programs - if they are available on the main site or elsewhere.)

Online tools

Lists of such software

Yes, questions asking to verify a solution are ok. It is good to include tag to indicate clearly that you are mainly looking for verifying your solution and potentially suggestions for corrections or possible improvements.

But it might be worth trying to ask in chat first. Especially, if you feel hesitant to ask the question for some reason (for example, you if think that the question is very specific and is unlikely to help other users). If you look at list of chatrooms, you can see that two calculus-related rooms exist (although they are not visited too often). And the main chatroom might be a reasonable choice, too. (This has advantage that almost at all time there are enough users there. The disadvantage might be that if there si a lot of discussion, your question might go unnoticed.)

This is only relevant for users with sufficient reputation to talk in chat - but I still think that in some cases chat might be useful before - or even instead of - posting on main.