In real life, we also need it to express quantitative relations and spatial forms, that is, the science of studying numbers and shapes. Due to the needs of life and labor, the most primitive human beings also know a little simple counting and a little calculation. And a "paper" is an article devoted to studying or discussing a certain problem.
Therefore, the significance of a mathematical paper is an article devoted to studying or discussing conceptual issues such as quantity, structural change and spatial model.
I think the math papers we are writing now should be divided into three categories. The first category is to write out the most thoughtful and impressive questions and solutions in the process of answering questions for discussion; The second category is to solve a new problem; The third category is the application of mathematics in life, which is a long application problem.
Several geometric problems are solved by the same formula (n(n- 1))÷2. For example, there are 10 points on a straight line, so how many line segments are there? The vertex with 10 rays is point o in AOB. How many angles are there? Here, we will discuss three topics.
There are 17 points on a straight line. Find the number of line segments on a straight line. A topic like this can be expressed by the formula (n (n-1)) 2. The process of this problem is17× (17-1) ÷1=136 (article).
If the length of line segment AB is 16, then the midpoint of line segment AB is C.D., E is the midpoint of AC and BC, and F, G, H and I are the midpoints of AD, DC, CE and EB ... Find the lengths of all line segments.
We can all convert it into the shortest line segment, one of which is 1.
1×( 1× 16+2× 15+3× 14+4× 13+......+ 15×2+ 16× 1)=2× 16+4× 15+6× 1 4......+ 18×9)=32+60 +84+ 104+ 120+ 132+ 140+ 144+ 144=960
A: Its length is 960 units.
Similarly, there are 17 rays on an angle, so how many angles are there on the graph of this problem? For topics like this, use the formula (n(n- 1))÷2 again. The process of this problem is17× (17-1) ÷1=136 (pieces).
If the angle AOB is 160 degrees, the midpoint of the line segment AB is C. D and e is the bisector of AC and BC. F, G, H, I are the bisectors of AD, DC, CE and EB ... Find the degrees of all angles. We can all convert it to the smallest angle, and the result is the answer after the above operation.
(n(n- 1))÷2 is a useful formula. It only took me a little time. Can you study it with me?