Hardest topics in high school math?

I'm prepping for some challenging math competitions and I'm just curious, what's the most difficult math problem you've encountered in high school?

Answer: The complexity of a math problem can vary widely depending on the specific subject you're working with. In typical high school math courses, here are some topics often perceived as particularly challenging:

1. Calculus: Concepts of limits and infinitesimals can be quite abstract, especially when you are introduced to them for the first time. Problems involving use of the Chain Rule, setting up and solving differential equations, and the ideas of integration and area under a curve (Riemann sums), can be quite challenging.

2. Geometry: The concept of proofs presents a new kind of thinking and can seem difficult for those new to it. Problems involving coordinate geometry, circle theorem proofs, and the use of trigonometry in geometry can also be tough.

3. Tensor Calculus: This is considered as one of the most advanced topics in high school math (typically covered in a special math program or math competition preparation), Tensor Calculus can be very challenging due to its abstract nature and its heavy reliance on linear algebra and multivariable calculus.

4. Combinatorics, set theory, and proofs: These topics go beyond standard high school curriculum, but frequently appear in math competitions. Comprehending and manipulating the principles of set theory, and dealing with combinatoric logic and counting methods, can be truly demanding.

Of course, remember that everyone's experiences with math vary! What appears difficult to one student might come naturally to another, and vice versa. Some students may find the logical aspect of proofs challenging, while others might struggle more with the abstract nature of calculus.

For math competition preparation, problems can get significantly more challenging with complex blend of these topics. Be sure to give yourself plenty of time to get comfortable with topics that are new to you. Practice makes perfect! Regular problem-solving can make you familiar with the methods and strategies required to tackle tough problems.