"Why 0.618?" 》Quadratic equation of one variable PPT courseware 3

Description

"Why 0.618?" 》Quadratic equation of one variable PPT courseware 3

As shown in Figure 2-8, a naval base is located at point A. There is an important target B 200 nautical miles due south of it, and an important target C 200 nautical miles due east of B. Island D is located at the midpoint of AC. There is a supply dock on the island; small island F is located on BC and just south of small island D. A warship starts from A and cruises at a constant speed from B to C, and a supply ship starts from D at the same time, traveling south-west The ship is sailing in a straight line at a constant speed to deliver a batch of items to the warship.

(1) How many nautical miles are there between Island D and Island F?

(2) It is known that the speed of the warship is twice that of the supply ship. The warship met the supply ship at E on the way from B to C. How many nautical miles did the supply ship travel when they met?

There is such an ancient Arabic arithmetic problem: There are two sums of money, one more and one less, the sum is equal to 20, and the product is equal to 96. The larger amount is promised to Said, so how much money does Said get?

This lesson selects some topics from geometry and real life, allowing students to experience the process of solving problems by formulating quadratic equations. When we construct mathematical models of equations, describe the real world, and solve practical problems, what important links should we pay attention to? ?

Review issues holistically and systematically

Grasp the equivalence relationship in the problem

Solve equations correctly and check the plausibility of solutions

Learning is a pleasure

1. There is a title in the "Pythagorean" chapter of "Nine Chapters of Arithmetic": "Now there are two people standing together. A's line is seven, B's line is three. B is going east, A is ten steps south, and is leaning northeast to meet B. Ask A and B the geometry of each row?"

The general idea is: It is known that A and B are coming from the same place at the same time, A's speed is 7, and B's speed is 3. B keeps walking east, and A first walks 10 steps south, and then diagonally to the north-east direction. After walking for a while, he meets B. Then how far have A and B walked when they met?"

Solution: Suppose the time it takes for A and B to meet is x. According to the meaning of the question, we get

(7x-10)²=(3x)² +10².

Sorted out: 2x²-7x=0.

Solving this equation, we get ∴x1=3.5, x2=0 (does not fit the meaning of the question, discard it).

∴3x=3×3.5=10.5, 7x=7×3.5=24.5.

Answer: A walked 24.5 minutes, and B walked 10.5 minutes.

2. In the residential design of Green Garden Community, a rectangular green space with an area of ​​900 square meters is planned to be opened between every two buildings, and the length is 10 meters longer than the width. So what are the length and width of the green space?

3. For a rectangular iron sheet with a length and width of 60 cm and 40 cm respectively, four equal small squares should be cut off from its four corners and folded into a rectangular parallelepiped sink without a cover, so that its bottom area is 800 square centimeters. Find the length of the side of the truncated square.

Keywords: quadratic equation teaching courseware, why is 0.618 teaching courseware, Beijing Normal University edition ninth grade mathematics volume PPT courseware, ninth grade mathematics slide courseware download, quadratic equation PPT courseware download, why is 0.618 PPT courseware download, .ppt format

For more information about the PPT courseware "Why is the quadratic equation of one variable equal to 0.618", please click the "Why is the quadratic equation of one variable ppt equal to 0.618ppt" tag.

"Why 0.618?" 》Quadratic Equation PPT Courseware 2:

"Why 0.618?" 》Quadratic Equation PPT Courseware 2 Do you know why the golden ratio is 0.618? Can you provide multiple design options for a rectangular garden? Can you make certain decisions based on the sales profits of goods? The same as linear equations and fractional equations ..

"Why 0.618?" 》Quadratic equation of one variable PPT courseware:

"Why 0.618?" 》Quadratic Equation PPT Courseware Learning Objective: How to get the golden ratio of 0.618. Further experience that equations are effective models for describing the real world. Be able to use equations to solve practical problems. Use mathematical beauty to decorate and beautify life. As shown in the figure...

File Info

Update Time: 2024-10-31

This template belongs to Mathematics courseware Beijing Normal University Ninth Grade First Volume Mathematics industry PPT template

Preview