For questions not addressed here, inquiries about video sponsorships, or anything else, you can find my contact info on the about page from Youtube (it's just my first name @ this url).
Question: What do you use to animate your videos?
Answer: I create the animations programmatically using a python library named "manim" that I've been building up. If you're curious, you can find it at https://github.com/3b1b/manim, but you should know that I developed it mainly with my own personal use case in mind. It's not that I want to discourage others from doing similar things, quite the contrary, but often my workflow and development with manim can make it more difficult for an outsider to learn than other better-documented animation tools.
There are aspects of producing videos in a software-driven manner like this that I find quite pleasing, but which are pleasing precisely because it's my own tool. It enforces a uniqueness of style, for example, which is by its very nature a benefit that can't be shared. There's also a certain freedom in being able to tear up the guts of the tool every now and then when I feel a change is in order, since backwards compatibility needs are very limited when you only care about videos moving forward. Not exactly the best practice from a collaborative standpoint.
All that said, if you do want to try it out, never hesitate to ask question, or to let me know about things that can be improved.
Question: What does the name "3blue1brown" mean?
Answer: When I started the channel, I knew that I wanted the logo to be a loose depiction of my right eye color: sectoral heterochromia, 3/4 blue 1/4 part brown. It was a way of putting a genetic signature on my work, and the channel is all about seeing math in certain ways. The name, of course, is just derived from the logo.
Question: What's the music playing in your videos?
Answer: For several I've just written my own simple background music. The piano song throughout the Essence of linear algebra, for example, is not actually a complete song, just enough musical doodling to fill in the intro/outro. Several recent videos have used a song kindly written by Vince Rubinetti.
Question: Who are you? What's your background?
Answer: My name is Grant Sanderson. I studied math at Stanford, with a healthy bit of seduction from CS along the way. For a while, my job experience was pointing me in the direction of software engineering/data science, but ultimately the primary passion for math won out at the expense of the mistress.
I've loved math for as long as I can remember, and what excites me most is finding that little nugget of explanation that really clarifies why something is true, not in the sense of a proof, but in the sense that you come away feeling that you could have discovered the fact yourself. The best way to force yourself into such an understanding, I think, is to try explaining ideas to others, which is why I've always leaned towards the teaching/outreach side of math.
I was fortunate enough to be able to start forging a less traditional path into math outreach thanks to Khan Academy's talent search, which led me to make content for them in 2015/2016 as their multivariable calculus fellow. I still contribute to Khan Academy every now and then, as I live near enough and we remain friendly, but my full time these days is devoted to 3blue1brown.
Question: Will you please make a video on <insert topic>!?!1!1!!
Answer: As you might imagine, I have a long list of topics I'd like to cover, so there's certainly no shortage of ideas. I don't want to completely ignore requests, though, so you're best chance of putting them in a place that I'll keep track of is this reddit thread. Keep in mind, though, that it's not like I use this thread as a checklist of what I'll necessarily do next. It's just a way to keep a pulse on what people are asking for.
Question (asked by wizrads on reddit): What resources did you use to get the mathematical knowledge you have today?
Answer: First of all, I should emphasize just how sparse the set of things I know is in the broader landscape of math, and the possible intuitions therein. I'm still always learning, and moreover always trying to refine how I learn, and I have no clear answers on what is best. So take anything I say with the knowledge that it should be heavily supplemented with advice that other (wiser) minds have to offer.
Much depends on what you want to learn in particular. As a high school student, I found the Art of Problem website and books fascinating and transformative, and I think their resources would be just as good for any adult looking to learn more. In general, I do think the best way to learn is to emphasize solving problems, rather than reading/watching alone. Math is fundamentally about patterns, and solving problems is a good forcing function for immersing yourself in patterns.
Moreover, it's not enough just to get an answer to a question, ask yourself if you feel comfortable with the underlying structural reason why the problem you are working on should even be solvable, and if the pattern of its solution might carry over to other contexts.
Through undergrad, here's a handful of books I found particularly well-written (I'm sure I'll forget some): -"Vector Calculus, Linear Algebra, and Differential Forms" by Hubbard and Hubbard - "Linear algebra done right", by Axler - "Ordinary Differential Equations" by Vladimir Arnold - "Chaos and Nonlinear Dynamics" by Steven Strogatz - "Primes of the form x2 + ny2" by David Cox - "An Epsilon of Room" by Terry Tao - "Topology" by Munkres - The expository papers written by Keith Conrad: http://www.math.uconn.edu/~kconrad/blurbs/ - I spent a lot of time with the Dummit and Foote modern algebra text, and it does make my recommendation list, but it's one of those texts that should be supplement with other texts that place more emphasis on motivation.
In reading, really try to predict what proofs will look like, and be willing to meditate on what the right way to think about a given object is. Ask yourself if each new construct feels motivated, or if it's out of the blue. If it is out of the blue, it's okay to move forward anyway, just keep note of the fact that there is a lurking question mark.
I hope that helps :)
Question (from a few patrons): Why did you make your total Patreon pledge amount private?
Answer (taken from a Patreon community post response): It might help to start with why Patreon introduced the feature. As I understand it, originally they modeled themselves loosely after crowdfunding websites like Kickstarter, where you actually do need to see the amount to know whether or not a project will happen.
For companies that run their own systems of sustained support, like Radio Lab or Khan Academy, it'd be a little strange to show what the total revenue is, since the contributions are not meant to push them over a threshold to make a project possible, but instead to reflect what value people individually derive from what these companies already offer. It'd be like having your doctor's salary written on the bottom of her name tag.
When I contribute to Radio Lab, I do so because I think they've added value to my life, and to that of others, and the nature of freely distributed content is that this value will not flow back to them without a conscious effort by listeners like me, the way it does in other industries. If they are starving and need that money, great. If they are absolutely raking it in and will use that money to fund more frequent and ambitious projects, great. From my perspective, I just want the value I got out of their content to make its way back to them.
Because the creators and companies Patreon aims to design its services towards are more analogous to those like Khan Academy or Radio Lab, they are shifting away from aspects inherited from crowdfunding platforms like Kickstarter to something more akin to what these companies do when they design their own systems.
With that as background, back to your question. I definitely understand the feeling that sometimes you want to contribute with a knowledge of how far that dollar will go for a given project. In fact, I'm right there with you and think about that every time I make contributions. But I don't actually think the existing pledge amount is a good measure of that; there's a certain independence between existing funds and the marginal benefit of more. Think of Warren Buffet contributing so much to the Gates foundation, not because they are in desperate need of funding, but because they've developed the infrastructure to ensuring those dollars go a long way. And on the flip side, there are plenty of poorly funded organizations which would not put new money to good use.
One thing I love about Patreon is that it sets incentives for creators to reach people more deeply, rather than simply reaching larger numbers of people regardless of depth. If people pledged based on what percentage of the total contributions their pledge would be (which, by the way, is not what I suspect most people do), there would be a perverse incentive for creators to start many smaller projects rather growing a single promising one to its fullest potential.
I suppose part of my motivation in aligning my page with what seems to be Patreon's future is to communicate my own sentiment that I want any contributions to be about the content, not the context. I'm incredibly grateful to every one of you who have chosen to pledge to 3blue1brown, and making the total amount private is not a matter of being opaque, it's my way of saying that I want you to contribute only if you think the videos are valuable. Even when you contribute to other pages whose total pledge amounts are public, I want you to do so not based on the number you see under the page title, but based on what that creator's content means for you personally, in the same way that you wouldn't weigh in Delta's market cap when buying a plane ticket.
By the way, fun fact, I used to be a street musician, and paradoxically a violin case full of money would bring in more than a case with just a few bills in it. So trust me, it's not like I'm here swimming in it and nefariously hoping to hide that fact from people so they think I'm in more need. Anyone who wants to know the total pledge amount can get a pretty good estimate looking at the number of supporters and the number of people I give special thanks to. Or honestly just asking me politely :). The goal is instead to maintain the independence discussed above.