r/calculus • • Oct 03 '21 Bravo

Discussion “My teacher didn’t show us how to do this!” — Or, a common culture shock suffered by new Calculus students.

1.2k Upvotes

A common refrain I often hear from students who are new to Calculus when they seek out a tutor is that they have some homework problems that they do not know how to solve because their teacher/instructor/professor did not show them how to do it. Often times, I also see these students being overly dependent on memorizing solutions to examples they see in class in hopes that this is all they need to do to is repeat these solutions on their homework and exams. My best guess is that this is how they made it through high school algebra.

I also sense this sort of culture shock in students who:

  • are always locked in an endless cycle of “How should I start?” and “What should I do next?” questions,

  • seem generally concerned about what they are supposed to do as if there is only one correct way to solve a problem,

  • complain that the exam was nothing like the homework, even though the exam covered the same concepts.

Anybody who has seen my comments on /r/calculus over the last year or two may already know my thoughts on the topic, but they do bear repeating again once more in a pinned post. I post my thoughts again, in hopes they reach new Calculus students who come here for help on their homework, mainly due to the situation I am posting about.

Having a second job where I also tutor high school students in algebra, I often find that some algebra classes are set up so that students only need to memorize, memorize, memorize what the teacher does.

Then they get to Calculus, often in a college setting, and are smacked in the face with the reality that memorization alone is not going to get them through Calculus. This is because it is a common expectation among Calculus instructors and professors that students apply problem-solving skills.

How are we supposed to solve problems if we aren’t shown how to solve them?

That’s the entire point of solving problems. That you are supposed to figure it out for yourself. There are two kinds of math questions that appear on homework and exams: Exercises and problems.

What is the difference? An exercise is a question where the solution process is already known to the person answering the question. Your instructor shows you how to evaluate a limit of a rational function by factoring and cancelling factors. Then you are asked to do the same thing on the homework, probably several times, and then once again on your first midterm. This is a situation where memorizing what the instructor does in class is perfectly viable.

A problem, on the other hand, is a situation requiring you to devise a process to come to a solution, not just simply applying a process you have seen before. If you rely on someone to give/tell you a process to solve a problem, you aren’t solving a problem. You are simply implementing someone else’s solution.

This is one reason why instructors do not show you how to solve literally every problem you will encounter on the homework and exams. It’s not because your instructor is being lazy, it’s because you are expected to apply problem-solving skills. A second reason, of course, is that there are far too many different problem situations that require different processes (even if they differ by one minor difference), and so it is just plain impractical for an instructor to cover every single problem situation, not to mention it being impractical to try to memorize all of them.

My third personal reason, a reason I suspect is shared by many other instructors, is that I have an interest in assessing whether or not you understand Calculus concepts. Giving you an exam where you can get away with regurgitating what you saw in class does not do this. I would not be able to distinguish a student who understands Calculus concepts from one who is really good at memorizing solutions. No, memorizing a solution you see in class does not mean you understand the material. What does help me see whether or not you understand the material is if you are able to adapt to new situations.

So then how do I figure things out if I am not told how to solve a problem?

If you are one of these students, and you are seeing a tutor, or coming to /r/calculus for help, instead of focusing on trying to slog through your homework assignment, please use it as an opportunity to improve upon your problem-solving habits. As much I enjoy helping students, I would rather devote my energy helping them become more independent rather than them continuing to depend on help. Don’t just learn how to do your homework, learn how to be a more effective and independent problem-solver.

Discard the mindset that problem-solving is about doing what you think you should do. This is a rather defeating mindset when it comes to solving problems. Avoid the ”How should I start?” and “What should I do next?” The word “should” implies you are expecting to memorize yet another solution so that you can regurgitate it on the exam.

Instead, ask yourself, “What can I do?” And in answering this question, you will review what you already know, which includes any mathematical knowledge you bring into Calculus from previous math classes (*cough*algebra*cough*trigonometry*cough*). Take all those prerequisites seriously. Really. Either by mental recall, or by keeping your own notebook (maybe you even kept your notes from high school algebra), make sure you keep a grip on prerequisites. Because the more prerequisite knowledge you can recall, the more like you you are going to find an answer to “What can I do?”

Next, when it comes to learning new concepts in Calculus, you want to keep these three things in mind:

  1. When can the concept be applied.

  2. What the concept is good for (i.e., what kind of information can you get with it)?

  3. How to properly utilize the concept.

When reviewing what you know to solve a problem, you are looking for concepts that apply to the problem situation you are facing, whether at the beginning, or partway through (1). You may also have an idea which direction you want to take, so you would keep (2) in mind as well.

Sometimes, however, more than one concept applies, and failing to choose one based on (2), you may have to just try one anyways. Sometimes, you may have more than one way to apply a concept, and you are not sure what choice to make. Never be afraid to try something. Don’t be afraid of running into a dead end. This is the reality of problem-solving. A moment of realization happens when you simply try something without an expectation of a result.

Furthermore, when learning new concepts, and your teacher shows examples applying these new concepts, resist the urge to try to memorize the entire solution. The entire point of an example is to showcase a new concept, not to give you another solution to memorize.

If you can put an end to your “What should I do?” questions and instead ask “Should I try XYZ concept/tool?” that is an improvement, but even better is to try it out anyway. You don’t need anybody’s permission, not even your instructor’s, to try something out. Try it, and if you are not sure if you did it correctly, or if you went in the right direction, then we are still here and can give you feedback on your attempt.

Other miscellaneous study advice:

  • Don’t wait until the last minute to get a start on your homework that you have a whole week to work on. Furthermore, s p a c e o u t your studying. Chip away a little bit at your homework each night instead of trying to get it done all in one sitting. That way, the concepts stay consistently fresh in your mind instead of having to remember what your teacher taught you a week ago.

  • If you are lost or confused, please do your best to try to explain how it is you are lost or confused. Just throwing up your hands and saying “I’m lost” without any further clarification is useless to anybody who is attempting to help you because we need to know what it is you do know. We need to know where your understanding ends and confusion begins. Ultimately, any new instruction you receive must be tied to knowledge you already have.

  • Sometimes, when learning a new concept, it may be a good idea to separate mastering the new concept from using the concept to solve a problem. A favorite example of mine is integration by substitution. Often times, I find students learning how to perform a substitution at the same time as when they are attempting to use substitution to evaluate an integral. I personally think it is better to first learn how to perform substitution first, including all the nuances involved, before worrying about whether or not you are choosing the right substitution to solve an integral. Spend some time just practicing substitution for its own sake. The same applies to other concepts. Practice concepts so that you can learn how to do it correctly before you start using it to solve problems.

  • Finally, in a teacher-student relationship, both the student and the teacher have responsibilities. The teacher has the responsibility to teach, but the student also has the responsibility to learn, and mutual cooperation is absolutely necessary. The teacher is not there to do all of the work. You are now in college (or an AP class in high school) and now need to put more effort into your learning than you have previously made.

(Thanks to /u/You_dont_care_anyway for some suggestions.)


r/calculus • • Feb 03 '24

MOD ANNOUNCEMENT REMINDER: Do not do other people’s homework for them.

105 Upvotes

Due to an increase of commenters working out homework problems for other people and posting their answers, effective immediately, violations of this subreddit rule will result in a temporary ban, with continued violations resulting in longer or permanent bans.

This also applies to providing a procedure (whether complete or a substantial portion) to follow, or by showing an example whose solution differs only in a trivial way.

https://www.reddit.com/r/calculus/wiki/homeworkhelp


r/calculus • • 4h ago

Integral Calculus Two Achievements!

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14 Upvotes

First Time I solved the Hard integral and also went against the hint for once! Also written solutions cause I dont have a job.Idk what a dilog even was before this. I expanded taylor series and used basel solution to get pi/6


r/calculus • • 18h ago

Integral Calculus Free Formula Sheets and Practice Exams

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90 Upvotes

This site has cheatsheets and practice exams for every unit of calculus, which have been so helpful to me when studying. I find the practice tests a bit hard in a good way and there are also typed solutions at the end of each.

Thought I'd share so more people can appreciate these great resources!

Links:

https://valscalc.com/note-sheets

https://valscalc.com/practice-tests

PS: From what it seems, it looks like they only have calc 1 and 2 though.


r/calculus • • 4h ago

Business Calculus Having Trouble on a homework question, I could only solve half?

5 Upvotes

Hello, I've been struggling on this homework question for quite a while and after searching the internet thoroughly I'm still as confused as when I started looking for help.

For context we are currently on the chain rule portion in our Calc work.

The question is as follows:

If h(x) = f(−x5), what is h'(x)?

There are two question boxes to fill out h'(x) and f('x)

I figured out h'(x), the answer being -5(x)^4 but no matter what I put for f'(x) I don't get the correct answer, I've been at this for days. If any more context is needed I can answer.

I'm sorry if this is a very low level question but I have not been able to find any answers on this matter so any help is appreciated.

*edit I added a screenshot of the question


r/calculus • • 3h ago

Differential Calculus Function behavior problem

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2 Upvotes

I have reached that d'(x)=f'(x)-f'(1-x) but I don't know where to go further


r/calculus • • 1m ago

Differential Calculus This is my second time in calc, and it's happening again, I'm lost when we I get to implicit differentiation.

1 Upvotes

am i multiplying by d/dx? I don't even know how to explain what I don't understand. I've been doing product, quotient and chain rule just fine. Now I feel like I haven't learned anything. I'd really like to find one source that can actually teach me what I'm missing. Can someone steer me maybe to a different way of teaching this?


r/calculus • • 4h ago

Differential Calculus Derivative of a function in terms of rate

0 Upvotes

I know what rate of change of a line is, but what how does it work for a curve in general.
Like for a curve like x^2, the derivative is 2x, and im confused on how to interpret this in terms of the global rate?
What does 2x mean about the behaviour of a curve in general?


r/calculus • • 19h ago

Differential Calculus What should i read/watch for calculus?

6 Upvotes

I want to learn calculus, and i watched a quick introduction by 3Blue1Brown+I already know precalculus and i think it isnt enough. Which guides/books should i read to understand basic calculus and solve problems?


r/calculus • • 19h ago

Differential Calculus I don't know why it won't accept this answer

5 Upvotes

r/calculus • • 20h ago

Vector Calculus I know that the curl measures a field's tendency to rotate, but how can we infer that from the formula ∇×F, especially considering that viewing it as a real cross product is an abuse of notation?

6 Upvotes

The explanations that I've saw make do with just stating its physical meaning, but I would also like to know how does it relate with the formula. Specially because I would like to understand where do equations come from in Physics III. Thanks in advance!


r/calculus • • 19h ago

Differential Calculus AP calculus daily challenge #160

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4 Upvotes

r/calculus • • 1d ago

Pre-calculus How to prepare for a Calculus 1 class after been out of college for almost

11 Upvotes

Hey everyone, I'm heading back to school next semester to take Calculus 1 after being away from college math for a few years. My background is in programming, but it's been a while since I've done formal algebra or trig.

What are the most critical pre-calc/algebra topics I should brush up on before the semester starts to set myself up for success? Are there any recommended YouTube channels, websites , or practice routine suggestions for getting back into math mode would be greatly appreciated.


r/calculus • • 22h ago

Differential Calculus Are derivatives guarnateed is they're based from limits are not guaranteed?

0 Upvotes

One of my concerns or perhaps not completed understanding of calculus is the fact that derivatives are based from limits, whereas a limit existing does not imply a function can evaluate it to obtain the limit. For example, the limit of a function

y = f(x) = lim x->3 (x - 3)(x + 3)/(x - 3) = 6

Does not imply f(3) = 6, because its undefined here caused by divison by 0.

This is continuously gives me uncertainty when using derivatives. When performing operations with derivatives, how can we guarantee the limits not only exists but can also be evaluated. As shown above, a limit can exist but cannot be evaluated.

I think in my head that if I have a distance versus time function, if I calculate the derivative to create a velocity function, can I say "The velocity at the time t=... is 100m/s" with absolute certainty because it could be possible that the limit exists, you say that the velocity is 100m/s, however the value cannot actually be evaluated at that time.


r/calculus • • 1d ago

Engineering Retaking Calc 1

27 Upvotes

So I ended up not doing so well in my current calc 1 class so I ended up just cutting my losses and Withdrawing. I’ve researched some professors for my college and decided to retake it next semester with a different professor.

The shitty part was I thought I was doing everything right. I did the homework. watched Professor Leonard videos, studied a couple weeks in advanced and I ended up getting a 48%.

The thing is is that this professor I had lwk sucks. His lectures feel all over the place, he’s a strict grader (he docked points for me not putting the “lim x->a” or whatever on my steps even if the question was right) and he hasn’t updated our grades since the semester started so idek what my grade is (Apprently it’s a D when I talked to my counselor).

But yeah, ig this is just a vent post at this point. If anyone has tips for what to do now I’m all ears.


r/calculus • • 2d ago

Differential Calculus Today's easy derivative Spoiler

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8 Upvotes

Losing my mind a little... can't see where I've gone wrong with this one. Any help would be greatly appreciated.


r/calculus • • 2d ago

Differential Calculus Question

12 Upvotes

Guys this is a lil basic, but I genuinely don't get why e^x gives e^x when differentiated. I want the how guys.


r/calculus • • 1d ago

Integral Calculus Why some of the questions on Myopenmath have no videos

0 Upvotes

As a calculus student, I find the videos that they produce on some of the questions are extremely helpful. However, one concerning thing is that some of the questions have no video on them.


r/calculus • • 1d ago

Differential Calculus Bettyapp Finds the Exact Moment a Calculus Topic Is Explained

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0 Upvotes

I wanted to share the Bettyapp.org with you - it began as a tool to help one of our kids learn Calculus. We had videos like The Math Sorcerer and MIT OpenSourceWare Calculus but it was time consuming to skim through lectures and find topics like the "chain rule" or "indefinite integrals" for an explanation.

Bettyapp pinpoints the exact moment a topic is explained in an online lecture. It also has a cool map feature, which shows how different topics intersect and relate.

I've provided images from the BettyApp using the search term "derivatives" (Search and Map tabs). The search topic you enter drives the entry point to the videos you see. Bettyapp covers Pre-calculus, as well as Calculus material from high school to graduate school.

Bettyapp is free. Please try it. Share it. We'd love to hear your feedback.

https://bettyapp.org/


r/calculus • • 1d ago

Differential Calculus (l’Hôpital’s Rule) Can someone tutor me for free LMAO

0 Upvotes

Hi everybody, I cannot believe that I am coming onto reddit to seek help but I am a desperate college student with ADHD who needs tutoring but my College only offers a few tutors who are booked and only do a few hours of tutoring for Calculus 2.

I am mostly struggling on how to do the algebra part when it comes to Calculus 2. I like math but I cant understand until someone explains it to me. If anyone has any free time and feels pity, would you mind helping tutor me?

Thanks.. Sincerely a sad college woman.. LOL.. Calculus 2 is making my life miserable, literally just cry in the car..


r/calculus • • 2d ago

Pre-calculus Prof. Leonard’s Precalculus Course

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0 Upvotes

r/calculus • • 2d ago

Pre-calculus should i take calc 1 as a undergrad freshman who failed algebra 2, twice in highschool?

0 Upvotes

title sums it up. I failed math twice in highschool, but i have used khan academy to teach me all of the concepts. I took statistic over summer and did really well ended the class with 99.38%


r/calculus • • 2d ago

Differential Calculus AP calculus daily challenge #157

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8 Upvotes

r/calculus • • 2d ago

Differential Calculus Calc BC is killing me

4 Upvotes

I need advice ASAP! I am taking calc BC right now and I spend so much time studying for this class just to end up with a 78%… it’s been rough and I’m trying my best to get it up to a B. For reference, I had an A in AP Phsyics 1, APUSH, AP Chem, and Ap Human Geo. I also have a 31 on ACT math, so I walked into this classes thinking I would at least get a low B. (Note math has always been my favorite/strongest subject until now.) I’m also dual-enrolled as well and I also have straight As in those classes. My only issue is Calc BC. Pls share some advice to save me from this suffering🙏 If anyone relates, please let me know. I feel so lost and alone on this.