In the midterm test, a student's average score in other subjects is 94. If mathematics is included, the average score in each subject is 95

In the midterm test, a student's average score in other subjects is 94. If mathematics is included, the average score in each subject is 95

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In the mid-term test, a student's average score in several subjects other than mathematics is 94 points. If mathematics is included, the average score is 95 points. It is known that he scored 100 points in mathematics. How many subjects did the student take?
(100-95) / (95-94) = 5,5 + 1 = 6, a total of 6 courses

Mathematical formula calculation (percentage)
20% of the number a is equal to one fourth of the number B. the number a is 80. Find the number B

80x 20% △ 1 / 4
=16 △ 1 / 4
=16x4=64
A: number B is 64

How to calculate the percentage of mathematics, we need the method!

A number is the percentage of another number, which is called percentage. Percentage is also called percentage or percentage. Percentage is usually not written in the form of fraction, but added "%" after the original numerator. For example, 90 / 100 is written as 90%, which means 90%, 1 + 30% = 130% 2. Oranges are 15% less than apples, oranges are 85% of apples 3. There are 30 boys in class 5 (1), There are 25 female students. How many percent more male students than female students? (30-25) △ 25 = 20% what percentage of male students in the whole class? 30 △ 30 + 25 = 54.55% (about) what percentage of female students in the whole class? 25 △ 30 + 25 = 45.45% (about) [or: 1-54.55% = 45.45%]

Proof of parallelogram rule
Experimental process

In mechanics, the law of parallelogram is often used to decompose forces
The experiment of this rule can be proved by the balance of force;
Three spring tensiometers can be designed, two along the adjacent side of the parallelogram, the other is the diagonal direction of the parallelogram, which can verify the parallelogram rule

How to prove the judgement of parallelogram

Connect diagonals and prove congruent triangles. Decision theorem 1 can be obtained by definition, decision theorem 2 can be obtained by decision theorem 1, and decision theorem 3 can be obtained by decision theorem 2

Does the physical vector equality of senior one also include the direction equality

The necessary and sufficient condition for the equality of non-zero vectors is that the size and direction are equal. This is a basic thing in high school mathematics
As for the zero vector, the size is equal to zero, arbitrary direction, but physics will not encounter

Is there a negative value of velocity as a vector in high school physics?

The positive and negative of the vector indicate the direction. There are negative values, but they only indicate the opposite direction. If you want to compare the size, just look at the number after the symbol
Scalar is different, size comparison should be combined with the symbol
O(∩_ Thank you. No, you can keep asking

When we study vectors, we know that velocity is also a vector. But in the difference between vector and scalar, there is one thing that vectors can't be added or subtracted directly. Can't they be added or subtracted in solving acceleration or other speed related quantities?

When doing kinematics problems, we should pay attention to the direction of acceleration and velocity. We can solve the problem by trigonometric function. For example, Xiaomin throws a ball horizontally from the air at a speed of 2 meters per second, We know the acceleration formula v = V0 + at, but we can't directly use 2 + 4G here (G is the acceleration of gravity). In this motion, the ball only receives the acceleration g given by the earth, but the direction of acceleration is different from that of velocity. It starts at a horizontal level and then gradually goes down, In this case, we can divide the motion into two parts: one is a horizontal straight line with uniform velocity, the other is a straight line with uniform acceleration. Apply the appropriate formula according to different situations, and finally use the vector triangle to get the final answer (note the direction). Sometimes we can use the trigonometric function to decompose the force or acceleration according to the parallelogram rule, Make acceleration and velocity in the same direction, and then add and subtract directly. Hope to help you ～

Triangle rule and orthogonal decomposition method
It is best to use specific graphics or examples to illustrate
How to put several forces on the coordinate axis?
What is the role of the triangle rule? Under what circumstances is it usually used?

If the resultant force of N forces is 0, then connecting them head to tail can form a closed n deformation (when n = 3, triangle rule)
Decompose the force to the ox, oy axis

Are parallelograms of equal perimeter equal in area?
Say the reason

Unequal
The reason is very simple, you grab a group of parallelogram diagonal pull to both sides, its bottom and perimeter are unchanged, but the height changes with the pull, so the area also changes