Question 28 of Higher Mathematics for Guidance!!

Must-see for graduate school entrance examination: The last two weeks before the decisive exam (3): Precautions before and after the exam.

1. Two days before the test, you must pay attention to:

1) No strenuous exercise.

2) One or two days before the test, take a shower and clean it to rejuvenate yourself.

3) Breakfast, lunch and dinner are complete, and the dietary standard should pay attention to continuity.

4) Keep warm and reduce the time you spend outside.

5) If you continue to review and read, do not exceed 8 hours a day.

6) Try to wake up at 7 a.m. and go to bed before 11:30 p.m.

7) Listen to some **, hum some songs, relax your spirit, and enjoy your mood.

8) Confirm the identity document, admission certificate, location of the examination room, and examination time;

9) Make sure you have all the necessary information and items such as knives, pencils, pens, rulers, erasers, glue, etc.

10) If you take the test in a different place or go out for the test, it is recommended to confirm the number of trains, evaluate the congestion period of the bus or subway, and strive to stagger the peak section and time, so as to reach the test room without barriers.

11) Choose the clothes, hats, and gloves to wear on the day of the test to put yourself in a good mood!

12) Exam pen recommendation, neutral black pen, it is recommended to prepare two nibs, one thin and one thick, two of each, if the roll paper is smooth, you can consider using a thicker gel pen, otherwise it is easy to pass through the paper, but political questions, it is best to use a thin gel pen to prevent wet test papers. Pencils should be prepared with 2b pencils as much as possible, and you can also buy special picture card mechanical pencils, with special picture card pencil leads, flat mouths. In any case, make sure that you have at least 2 pencils or 1 self-carding pencil.

2. About admission:

1) Try to arrive at the exam room a quarter of an hour in advance, and especially remind those who are not in a hurry not to get into trouble before the exam because of this.

2) For big cities, if the test center you are applying for is far away from your accommodation, it is recommended to wake up early or stay in a hotel near the test center so that you can get to the test center the next morning. However, for such candidates who stay in hotels near the examination room, they must book a room in advance, and it is expected to book a room 5-7 days in advance, otherwise it will be difficult to find a suitable room, after all, there are many candidates, and there are not a few people who think about it. It is recommended that in order to ensure that the room is quiet and the condition is satisfactory, and to create good sleeping conditions, it is recommended to stay two days before the test to adapt to the accommodation in this hotel.

3) To take into account the factor of traffic congestion, it is recommended to get up early to take a bus or take a taxi.

4) Before departure, be sure to check whether you have all kinds of documents and test tools!

Student, this is linear algebra, okay?

Let f(x)=e x-x-1

f‘(x)=e^x-1=0

When x=0 is obtained, f(x) obtains the minimum value.

So f(x)> f(0)=0

i.e. e x> x+1

Regardless of whether x tends to 0 from the left or from the right, the limit of tanx x is 1, x tends to 0 from the left, 1 x tends to negative infinity, and 1 x of e tends to 0, then the limit of the function tends to 1

x tends to 0 from the right, 1 x tends to positive infinity, and 1 x of e tends to positive infinity, then the limit of the function tends to 1

The left and right limits of 0 exist but are not equal, and are the jump breaks in the first type of discontinuity.

Hello, please send me the question.

Cover your face] [cover your face] [cover your face] [cover your face].

There are too many, please choose up to two for you.

You have a total of 6 questions, high math.

Ask the first two.

The second question uses this, I forgot the square just now, I'm sorry.

If you still need to continue to answer, please re-initiate the consultation [cover your face] [cover your face] and come to [ok] [ok] [ok].

The two partial derivatives are.

zx=x/√(x²+y²)

zy=y/√(x²+y²)

At the point (1,1), the gradient of z is .

grad z=(zx,zy)=(1 2,1 2) Therefore, the maximum value of the direction derivative is the modulo of the gradient.

grad z|=1/2·√2

It's okay to set it to h, you can look at the process of the two questions first.

It's also cleverly set, so as to reduce the difficulty of calculation, as for your problem to set the height to 2h, I don't see the ingenuity, so you can set it to h.

This problem examines the sufficient and necessary conditions for the integral of the curve to be independent of the path, and the integrand function is easily satisfied according to the integral of the curve.

Partial p bias y = partial q partial x, as long as it is a closed curve, then the integral is zero. It should be noted that in the integrand function x≠0, that is, all points on the curve x≠0, only option c is correct, although the other options seem to be closed curves, after removing x=0 points, they are not closed curves.