Question 2: I hope I can help you with the final question and answer of senior one mathematics.
1. It is known that the vertex of the equilateral triangle ABC is placed at point A, and the triangle rotates around point A, and both sides of the 60-degree angle intersect with the bisector of the straight line BC and point D and ∠ACB respectively at point E. (1) When D and E are on the bisector CM of BC and ∠ACB respectively, as shown in figure/kloc-. (2) When D and E are on straight lines BC and CM respectively, as shown in Figures 2 and 3, what is the quantitative relationship among DC, Ce and AC? Please write the conclusion directly. (3) In Figure 3, when ∠ AEC = 30 and CD=4, find the length of CE.
answer
Proof: Because EAD = BAC = 60.
So ∠ bad = ∠ EAC
It is also a regular triangle ABC, so AC = AB.
Because ∠ ACB = 60 and CM is the bisector of ∠C,
So ∠ ace =1/2 (180-60) = 60.
That is ∠ ace = ∠ ACB.
So triangle ABD and triangle ACE are congruent.
So db = ce, so DC+ce = CD+BD = BC = AC.
2) Figure 2: DC-CE = AC
Figure 3: CE-CD = AC
All proofs are to prove the congruence (ASA) of triangle ABD and triangle ACE.
3) Because ∠ ACM = 60 = ∠ B
∠BAD=∠CAE，AC=AB
So triangle ABD and triangle ACE are congruent.
So ∠ ADB = ∠ AEC = 30.
Because ∠ b = 60
So triangle ABD is a right triangle with an angle of 60,
So BD = 2ab, so BC = DC = 4.
So ce = 8
2.wenku.baidu/...3
The content of this website is the title. Do it first, and you won't ask questions.
In fact, you can go to Xinhua Bookstore to buy a slightly more difficult book, or you can.
Question 3: The finale of junior high school mathematics and geometry is a kind of inquiry. The topic is very big, and there are several pictures. How to do it? I have no idea at all. The general finale is divided into three small topics. The first two small topics must be very simple, and the last one who has the ability to do it can't. There are so many finale questions, who knows which one to take? So you can't lose the basic questions in front, so you can do it.
Question 4: What are the main review methods for the geometric finale in senior high school mathematics? Give you some ideas: 1. Chapter review. No matter which subject is divided into big chapters and small classes, when all the classes in a chapter are finished, the whole chapter will be strung together and told systematically. As a review, we can also do this, because since it is a chapter of knowledge, all classes must be related before, so that we can find it. 2. Review by turns. Although we study more than one subject, some students like a single review, such as poor Chinese. They have been working hard to review Chinese and don't ask other subjects at all. In fact, this is a bad habit. People who do something repeatedly for a long time will inevitably get tired, which will lead to burnout and fail to achieve the expected results. Therefore, when we review, we should not review a single subject, but let them take turns.
Question 5: The geometric finale of the first grade in Jiangsu (1) AD=BE.
(2) ∠BCA-∠ACE, ∠BCE=∠ACD, SAS, congruent triangles corresponding edges are equal.
(3) It is considered that ∵ they are equilateral triangles ∴ CD = cecb = ca ∠ BCA = ∠ ECD = 60.
∴∠BCA+∠ACE=∠ECD+∠ACE ∴ ∠BCE=∠ACD
∴△BCE?△ACD(SAS)∴ad = be