I can only talk about the solution in general, it's too much trouble to type the answer.

1, using Robida's law, the result is 2.

2. Use the formula to get the derivative, and then substitute it into 1.

3, you can get two tangents, and you need to abandon one.

4. Parts integration,

5. Directly apply the derivative formula of composite function.

6. Find the first reciprocal and then calculate the extreme value.

The topic is not very difficult, but the calculation is quite large and troublesome.