1 mm is equal to how many wires, how many μ and the length unit below mm

1 mm is equal to how many wires, how many μ and the length unit below mm

1 mm is equal to 100 wires, 1000 microns, 1000000 nanometers and 10000000 angstroms

On the unit of length in ancient China
In ancient times, the length unit of each dynasty is about the present (meter) (at least tell me the Northern Song Dynasty). What are the length units

Unit of length
1 Li = 15 yin = 150 Zhang
1 lead = 10 Zhang
1 foot = 2 steps = 10
1 step = 5
In the Zhou Dynasty, it took eight feet as a step, while in the Qin Dynasty, it took six feet as a step?
1 foot = 10 inches
1 inch = 10 points
1 point = 10%
1 cm = 10 millimetres
1 millimetre = 10 filaments
1 silk = 10 Hu
Conversion:
2 li = 1 km (ancient Li and Shi Li are different in length)
3 feet = 10 meters
3 feet = 1 meter
3 inches = 10 cm

The trajectory equation of the midpoint of the line connecting point P (4, - 2) and any point of circle x2 + y2 = 4 is ()
A. （x-2）2+（y+1）2=1B. （x-2）2+（y+1）2=4C. （x+4）2+（y-2）2=1D. （x+2）2+（y-1）2=1

Let any point on the circle be (x1, Y1) and the midpoint be (x, y), then x = X1 + 42y = Y1 − 22x1 = 2x − 4Y1 = 2Y + 2, substitute x2 + y2 = 4 to get (2X-4) 2 + (2Y + 2) 2 = 4, and simplify to (X-2) 2 + (y + 1) 2 = 1

Write out a group of integer solutions, a group of negative integer solutions and a group of positive integer solutions of the quadratic equation 4x-3y = 15
Write down the process of each step

X=3(Y+5)/4
Because x is an integer, as long as y + 5 is an integral multiple of 4
So a set of integral solutions are: x = 6, y = 3
A set of negative integer solutions are: x = -- 3, y = -- 9
A group of positive integer solutions are: x = 9, y = 7

In the definition of ellipse, how to understand the locus of a point whose ratio of the distance to a fixed point to the distance between a fixed line is constant?
What is the guide line?

Actually: there are some points like P,
The distance from point P to the fixed point (that is, the focus of the ellipse) is x1
The distance from point P to the fixed line (i.e. ellipse directrix) is x2
X1 / x2 = const (constant value), i.e. the ratio of the two is the same value E (i.e. ellipse eccentricity)
The trajectory of such a point P in coordinates is an ellipse

Use appropriate methods to solve the following equations: (write out the process of solving the equations and the methods of solving the equations: such as factorization, collocation, formula, etc.)
（1）12x2-1/3=0 (2)x2x-2x-4=0 (3)5x2=9x+2 (4)5x2+2x=0

12x & # 178; - 1 / 3 = 0 direct leveling method 36x & # 178; = 1x = ± 1 / 6x & # 178; - 2X-4 = 0 formula method X & # 178; - 2x + 1 = 5x = 1 ± √ 55x & # 178; - 9x-2 = 0 factorization (5x + 1) (X-2) = 0x = - 1 / 5 or 25X & # 178; + 2x = 0 factorization x (5x + 2) = 0x = 0 or - 2 / 5

How many days has it been from October 8, 2012 to today? Today is December 13

Oh, my God!

Ask a math problem in grade four of primary school
Let's find a simple formula: 0.0695 * 2500 + 695 * 0.24 + 51 * 6.95!

0.0659*2500+695*0.24+51*6.95
=6.95*25+6.95*24+51*6.95
=(25+24+51)*6.95
=100*6.95
=695

How many days from July 12, 2010 to December 19, 2013?

The interval is 1255 days, including the first and last two days is 1257 days
The program calculation is accurate

The purchase price of a garment in a clothing store is 100 yuan, and the price is 121 yuan after two consecutive price increases. Given that the growth rate of two price increases is the same, what is the growth rate of each price increase?

100×(1+x)^2=121
x=10%