WARNING: Professor Karthik is a weeb that likes One Punch Man!
Jokes aside, Professor Karthik gets a lot of slack for being a "bad lecturer" and a person who focuses more on conceptually understanding the material rather than simply applying techniques to solve problems. I found his approach to be, while sometimes overbearing, more helpful in the long run than other math professors.
Your grade will consists primarily of homework, two midterms, and one final, all of which will be posted on Gradescope. The homework consists of textbook problems and his own personal problems; the textbook problems will be a breeze, while his problems will require a bit more thinking. His midterms are mostly easy computational problems with a few problems testing your conceptual knowledge. His final is also similar, but consists of more conceptual problems; none of his exams are super difficult, but it wouldn't be fair to say that they are a breeze either.
Karthik's method of lecturing initially began with lecturing on the blackboard, but he switched to slides after our review and inputs, which worked out much better. He does go a little too quickly with his slides, but asking him to go a few slides back will generally get him to slow a bit. Other than that, his lectures are fairly standard; they get the material across, and that's about it. You learn. That's what you're here for anyways.
Overall, Karthik left a really bad impression in his first few weeks, but improved immensely over the next few weeks, making him one of the few professors at UCLA that actually adapt to his students rather than the other way around. I suspect that he'll continue using slides in the future, and that he'll mellow out and became a better lecturer by next quarter. I would rate him a 3/5 overall for now, but note that he will probably become better as time goes on.
PS: Karthik really cares about his students, but he does send out a rather excessive amount of emails pertaining to important information. Prepare your inboxes to be spammed (but do read the emails, they're usually helpful.)

In short: DO NOT TAKE THE CLASS WITH THIS PROFESSOR

The long story:

First of all, the class is graded on a straight scale which is pretty dumb for a math class that is not 31A or 31B. His lectures are very boring. He usually speaks very fast and is usually not in sync with what he writes on the board (he used slides after week 5 or so) and what he speaks which makes it difficult for students to follow the class. He is a very picky and annoying person - his homework often have one or two really weird problems that are pretty hard to solve. He initially asked for students to submit HW at 7am on Friday during thanksgiving week, so you can imagine how annoying he is. He later changed the deadline of course.

He is also very picky about the idea of using "Change of Variables" instead of u-substitution which honestly makes no sense. He sends out at least five emails each week (half of these emails would be him fixing his typos in previously written emails). Even in his lectures, he usually makes a lot of mistakes and the class stands confused.

Moving on to his exams, I would say that they would be fair if the class was curved. The first midterm was pretty easy; however, things started getting a little tricky towards the end, and this is coming from someone who has done MATH 33A. You will be able to do well in this class if this is your only hard class. If you are taking multiple hard classes, then do not take a class with this dude, you will end up being a jack of all trades and master of none.

Before I say more I must in some large aspect credit my poor grade in this class to not having had taken 33A before this. The class doesn’t use it initially but 33A material slowly ramps up and if you haven’t taken it you will get quite lost this last week.

That said, the main purpose of this review is to warn people of Karthik. This is the first quarter he is teaching and I respect him for trying to take steps to save the class, it didn’t really help much. The man’s lectures are poor, generally uninteresting and often all over the place. He has odd requirements for mathematical rigor which drove the TAs insane to figure things out.

All in all, it’s been a rough first quarter for Karthik. I hope he figures it out.

As an engineer by training (and as someone who lectured for the first time in his life) he taught Diff Eqs very well. While his first lectures on the board were very scatterbrained, the slides later were very helpful, and he actually lectured well. I like how we went out of his way to describe applications of Diff Eqs, unlike other professors who only care about the math and not the applications. He also went out of his way to learn names too.

Homework was light, but graded for correctness. Both the textbook and the solution manual can be found for free, so with the two, HW points are freebies. The tests were hit and miss. Computationally simple, but a good number of questions required derivations and/or proofs. Karthik also made conceptual problems on the homework, which were helpful with concepts, but felt strange for a computation-based class.

He got a lot better very fast, and I’m sure he’ll be even better next quarter.

DO NOT TAKE HIM. You're Welcome.

Nice guy but not a great professor. The class has 2 midterms, 10 homework assignments, and a final. His lectures are pretty boring and he usually flips through slides that are riddled with errors, often confusing himself as well as the class. The homework problems are a mixture of problems from the textbook and ones he writes himself, but the annoying part is he grades on accuracy so if you don't take the time to make sure everything is fully correct you can get docked on homeworks pretty easily.

However, the rubric has a 90% weightage on midterms and the final, and given that the first midterm was a joke and the second was pretty easy as well, as long as you did well on those, you should have been fine. The final wasn't too bad but he graded somewhat harshly in my opinion, and asked an assortment of strange conceptual questions that sometimes hinged on remembering random exceptions.

He writes these long emails before midterms and occasionally somewhere in the middle, usually to inform you what to know and what students are messing up on. They can be somewhat tedious and occasionally include ranting but overall were pretty useful in clarifying his expectations.

Overall pretty forgettable class but could have been worse for sure.

The professor wanted us to do the hard way of solving problems because we “didn’t understand the concept fully of the easy way.” I learned more from the book but it wasn’t enough. I didn’t even fail the midterms but failed the class sooo. First midterm was too easy, second one was harder. The curve won’t save you :(

In all honesty, I feel like Professor Karthik gets a bad rap.

One thing right off the bat: he makes a lot of typos. He's clearly very scattered when writing things down or preparing slides, and as a result a lot of marks/variables/signs are missed when he's writing down equations. In my opinion, however, it's pretty easy to decipher what he means when he's writing them down, and if you correct him he immediately looks for the mistake and corrects it on the spot. If you're someone who likes their professors to be 100% on it all the time, you'll probably have a rough time in this class.

If you can handle that caveat, however, you should know that he likes to take a very conceptual approach to the learning process. A lot of people are bothered about how strict he is on notation (specifically in u-substitution), but it's really not that hard to adapt, and I found that writing things that way gave me a better idea of what's really going on in the actual math itself.

I personally enjoyed this class very much. The material was interesting, he knows what he's talking about, he likes to discuss real-life applications of the topics, and he's very helpful if you go to his office hours. The midterms are almost all calculation and are very doable, and the final is a little rougher – nothing that's unexpected for a math class.

I understand that not everyone will jive with his teaching style, but if this sounds like a class you would do well in then I would definitely recommend him.

This was probably one of the worst math classes I've taken at UCLA. The entire class felt like it was haphazardly thrown together with Karthik changing his lecture style throughout the quarter from confusing notes of the board to powerpoint slides which were riddled with mistakes. Karthik was also extremely picky about seemingly random concepts, such as not allowing us to use differential form for exact differential equations because we "did not understand the mathematical reason why this form works". Things like this were particularly irritating when online learning materials and the textbook would teach concepts in ways that Karthik deemed illegal in this class, leaving you to decipher his incomprehensible notes in order to not get points removed on the tests. When it came to exams, if you really understood the homework and did all of the practice exams he gave, this would really only prepare you to get a C on the exam. To earn a grade beyond this, you often had to rely on your ability to do things like construct proofs about various course topics even though constructing proofs was never covered in class. Definitely not an enjoyable math class by any stretch of the imagination

Honestly his lectures are completely useless. I stopped going to class like week 2 and did fine. You can just read the textbook and get a better grasp of the material and then use his lecture notes (he started using ppts and put them up during like week 5). Honestly I really disliked him during the class but hes not actually a bad or really unfair professor. He responds to emails and questions consistently and also put up his own explanation and work for tough problems/proofs which ended up being on the final. The thing really irritates me (and other students) was the fact that he is super picky about mathematical notation and other small math-y stuff (weird considering his engineer?!) and even went to the lengths of putting questions solely about proper math processes on the final. He also didn't curve but considering the averages of the midterms and final were pretty high for a math class I can understand that.