Elementary math solves the volume of the triplex body. 10

Take either side, because it is an equilateral triangle, let the bottom edge be a

The height of the side triangle is a 3 2

Through the bottom triangle to make the perpendicular line of the bottom edge of the side triangle.

This distance is 1 3 of the height of the bottom edge of the bottom triangle on the bottom of the base

The height on the bottom edge of the bottom triangle is also a 3 2

These two sides and the height of the vertex towards the base form a right triangle.

The hypotenuse is a 3 2 straight angle a 3 6 the height of this positive Mitsubishi body.

It is also the length of another right-angled side: a 6 3

The area of the bottom triangle is: a 2 * 3 4

The volume of the pyramid is the base area of 3 high

The method of finding the volume of a cone when I learned in elementary school can be demonstrated.

The pyramid is one-third of the volume of a prism.

The pyramid is one-third of the volume of the prism is well proved, and I remember that the method in the mathematics book of the high school teacher version is very similar to calculus, that is, each of its faces is subdivided, and then this "face" can be regarded as a cylinder, and its "volume" is a quadratic function about the height, so it is infinitely subdivided and then added, you can use 1 2 + 2 2 + 3 3 +...n 2 = n(2n + 1) (n + 1) 6, and then it can be proved.

In short, the integral of y=x 2 is y=1 3x 3+c

It is best to multiply the most original base area by the height and divide by 3

Let the side length of the positive Mitsubishi body be a

Therefore, its bottom area is 3a square 4

Its height is 6a 3

Its volume is the root number 2a cube 12

The tetrahedral volume is one-third of the corresponding cube volume.

Can you use the cut-and-patch method to divide a cube into three regular tritsubishi bodies?

There can be several algorithms for the volume of a square

Knowing that the reciprocal sum of three prime numbers is 1879/3495, what is the sum of these three prime numbers?

1 A + 1 B + 1 C = 1879 3495 = Then apparently one of the prime numbers is 5, 1879 3495 - 1 5 = 1180 3495 = 236 699

699 is a multiple of 3, then there must be a prime number of 3

Mathematics is a very important subject, if mathematics only learns textbooks, it is impossible to learn well, there must be a teacher to lead, point, deepen, high school mathematics is mostly function-based, and the connection with junior high school is only some basic concepts of junior high school, such as judging the conditions of parallelograms, so it doesn't matter if junior high school mathematics is not good, but you must study hard in high school, listen carefully in class and follow the teacher's ideas, you must do more math problems after class, even if the teacher does not assign, you have to do it, you can't be lazy, you can't ask, I also have to learn to summarize, and I believe that if you do the above, you will be able to learn well.

Hello, elementary mathematics generally studies special problems, while higher mathematics studies generally general, more complex problems, for example, if you find the volume of a very irregular geometry, then you can't use any formula to find it directly, only through calculus.

University physics is also a very general problem, not a special one. Then it is very necessary to have a foundation in advanced mathematics, and many physical problems can only be completely solved by the knowledge of advanced mathematics, kinematics, electricity, etc.

The same is true for other areas, which I will not enumerate.

The questions are incomplete, and there are a lot of them, almost one test paper.

Mathematics originated in the 4th century BC. Before the 6th century B.C., mathematics was mainly about the study of "numbers". Mathematics developed during this period in ancient Egypt, Babylon, India, and China was mainly counting, elementary arithmetic, and arithmetic, while geometry could be regarded as applied arithmetic.

From the 6th century BC onwards, the rise of Greek mathematics highlighted the study of "form". Mathematics then became the study of numbers and shapes. Aristotle, a Greek philosopher in the 4th century BC, defined mathematics as "mathematics is the science of quantity."

The meaning of "quantity" is vague and cannot be understood simply as "quantity". ）

Until the 16th century, the English philosopher Bacon divided mathematics into "pure mathematics" and "mixed mathematics". In the 17th century, Descartes argued: "All sciences which have the purpose of studying order and measurement are connected with mathematics."

In the 19th century, according to Engels, mathematics can be defined as: "Mathematics is the science that studies the relationship between spatial forms and quantities in the real world." ”

Since the 80s of the 20th century, scholars have defined mathematics simply as the science of "patterns": "The field of mathematics has become known as the science of patterns, and its purpose is to reveal the structure and symmetry that people observe from the abstract world of nature and mathematics itself. ”

The number originated in ancient Egypt, Babylon, and India. These were invented by primitive people in ancient times, who used animal bones to carve the food, time, calendar, etc. they needed.

Mathematics: The word bai is derived from the ancient Greek word du in the West, which means to learn, to learn

Scientific DAOs, and other narrower and more technical meanings. The ancient Greeks introduced names, concepts, and self-thinking into mathematics, and they began to guess how mathematics came about early on. Although their speculations were only hastily written down, they almost first occupied the realm of conjecture.

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Mathematics originated in the early production activities of human beings, and the ancient Babylonians had accumulated a certain amount of mathematical knowledge since ancient times and could apply practical problems

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The limit thinking method is an indispensable method for mathematical analysis and even all advanced mathematics, and it is also the essential difference between mathematical analysis and elementary mathematics. The reason why mathematical analysis can solve many problems that cannot be solved by elementary mathematics (such as finding instantaneous velocity, curve arc length, surface area, surface volume, etc.) is precisely because it adopts the method of thinking of limits.

Sometimes when we want to determine a certain quantity, we must first determine not the quantity itself but its approximation, and the approximation determined is not just one, but a series of increasingly accurate approximations; Then, by examining the trend of this series of approximate values, the exact value of that quantity is determined. This is the method of thinking that uses limits.

The bottom surface of the cuboid wide hall is a square with a side length of 30-x, and the height is x, so the volume of the body is x(30-x) 2, and then 7,6,5,4 is substituted into it, and it can be the largest when x 5 is obtained, so choose c