1. the problem of finding the domain: the denominator in the fractional function cannot be equal to zero, and the numerator depends on the specific situation. Some of them contain root numbers, and the root number should be greater than or equal to zero. Other special cases will be analyzed when they encounter problems. Special attention should be paid to: to find the domain, the final result must be expressed by interval, not by set.

2. Evaluation questions can be directly substituted without too much explanation.

3. Decompose the composite function into a simple function, as long as the function is set layer by layer, and it is set as the simplest linear function, quadratic function, exponential function, function, power function, etc. , not much explanation.

4, derivative function, the correct use of derivative formula, simple and clear, not much explanation.

5. Finding the second derivative means finding the second derivative of the original function, that is, the derivative function of the derivative function of the original function, which is very simple and does not need much explanation.

The above problems are only relatively simple problems in high school mathematics. It's no use knowing the answer. You need to do more questions and understand them deeply.