Cube of (x-1) = 8 to find the value of X

Cube of (x-1) = 8 to find the value of X

Cube of (x-1) = 8
x-1=2
x=3

Which ball is the biggest on the planet? Star? Moon? Earth? Mars?

Some red dwarfs in stars are smaller than the sun and generally larger than the sun
The diameter of the earth is about 1 / 2 larger than that of Mars, about 4 times that of the moon

A right angle side ab of a right triangle board is 1.5 meters long and covers an area of 1.5 square meters. To process it into a square desktop with the largest area, the processing methods of students a and B are as follows. Please use your knowledge to explain which student's processing method meets the requirements. (the processing loss is ignored, and the score in the calculation result can be retained)

In the method of a (Fig. a), let the side length of a square be y, ∵ de ∥ AB, ∥ cdbc = deab, i.e. 2 − y2 = y1.5, and the solution is y = 67m. In the method of B (Fig. b), let the side length of a square be x, and let the side length of a square be AC The height BM = 2 × 1.552 = 1.2m. ∵ quadrilateral defg is a square, ∵ de ∥ AC, ∥ BDE ∥ BCA, ∥ deac = bhbm = 1.2 − x1.2, that is, X52 = 1.2 − x1.2. The solution is x = 3037m. ∵ 3037 ∥ 67, and the method of∥ a meets the requirements

The square of X + X-1 = 0 prove the cube of (x + 1) - (x-1) = 8-6x

(x + 1) &# 179; - (x-1) &# 179; = [(x + 1) - (x-1)] [(x + 1) &# 178; + (x + 1) (x-1) + (x-1) &# 178;] = 2 (3x & # 178; + 1) substitute the known X & # 178; + X-1 = 0 to get X & # 178; = 1-x into the original formula = 2 (3x & # 178; + 1) = 2 (3-3x + 1) = 8-6x

According to the drawing of 1 / 200 scale, the length and width of a test field are 4cm and 3cm respectively. Calculate the actual area of this field

The actual length is 4 × 200 = 800 cm = 8 M
Width = 3 × 200 = 600 cm = 6 m
Area = 8 × 6 = 48 square meters

The story of mathematicians is about 100 words
Don't ask others to answer, it's better to be junior one or above

In 1725, John Bernoulli's son Daniel Bernoulli went to Russia and recommended Euler to czar kadrin I. in this way, Euler came to Petersburg on May 17, 1727. In 1733, Euler, who was only 26 years old, became professor of mathematics at the Petersburg Academy of Sciences. In 1735, Euler solved a difficult problem in Astronomy (calculating comet orbit), It took several famous mathematicians several months to solve this problem, but Euler finished it in three days with his own method. However, his overwork made him sick in the eye, and unfortunately he lost his right eye. At that time, he was only 28 years old. In 1741, at the invitation of Peter the great of Prussia, Euler went to Berlin to work as director of the Institute of physics and mathematics of the Academy of Sciences until 1766, Later, he returned to Petersburg under the sincere invitation of Czar kadrin II. Unexpectedly, soon, his left eye eyesight declined and he was completely blind. Unfortunately, the fire in Petersburg in 1771 hit Euler's house. Euler, 64, who was ill and blind, was trapped in the fire, although he was rescued from the fire, But his study and a large number of research results were all reduced to ashes
He vowed to take back the loss. Before he was completely blind, he could still see things dimly. He grasped the last moment, wrote the formula he found on a big blackboard, and then dictated the content, which was recorded by his students, especially his eldest son A. Euler (mathematician and physicist), He still struggled with darkness with amazing perseverance and studied with memory and mental arithmetic until his death for 17 years

How to divide a right triangle with an angle of 90 ° and another angle of 30 ° into three triangles with the same shape and size

Divide the 60 degree angle equally, intersect the other right angle side at point D, and make a vertical line from point d to the hypotenuse
These three small right triangles are congruent

Elevator motion belongs to rotation phenomenon

Elevator movement should be divided into several parts: carriage is linear motion (only up or down); elevator door is also linear motion (open or close); the steel cable of traction elevator is driven by motor for circular motion, which is rotating, etc

If the angle between a and B is 60, | a | = | B | = 1, then 2A times B=_______ .

Vector multiplication principle = 2 * | a | * | B | * cos60 = 1

As shown in the figure, ∠ C = 90 ° in △ ABC, MD is the vertical bisector of AB, intersecting BC with D, intersecting AB with m, BD = 8cm, ∠ ADC = 30 ° to find the length of AD and AC