The radius of a certain pollen grain is about 25um. How many pollen grains can be arranged up to 1m in sequence? Where 1um = 10 ^ - 6 (m) (the results are calculated by scientific method) The calculation process is detailed and fast

The radius of a certain pollen grain is about 25um. How many pollen grains can be arranged up to 1m in sequence? Where 1um = 10 ^ - 6 (m) (the results are calculated by scientific method) The calculation process is detailed and fast

1m / 50um = 1 / (50x10 ^ - 6) = 2x10 ^ 4

The radius of a pollen grain is 25um_____ The number of such pollen grains arranged in sequence can reach 1m? (expressed by scientific counting method)

If the radius is 25um, then its diameter is 50um. The answer is 2 times 10 to the fourth power

The diameter of a kind of pollen is 10-4 cm, expressed as a decimal

The answer is 0.0001cm

The diameter of some pollen grains is about 50 nm______ The number of such pollen grains in sequence can reach 1m. (1nm = 10-9m, the results are expressed by scientific notation)

First, 50 nm is converted to 50 × 10-9 m, which is expressed as 5 × 10-8 m by scientific notation, and then 1 m △ 5 × 10-8 M = 2 × 107

A piece of aluminum can make a cube frame with 6cm edge length. If the aluminum is made into a cuboid frame with 8cm length and 5cm width, how much space does the cuboid frame occupy?

wzl513031,
Aluminum length: 6 × 12 = 72 (CM)
Cuboid height: 72 △ 4-8-5 = 5 (CM)
Frame occupancy: 8 × 5 × 5 = 200 (cm3)

Let the real numbers a and B make the equation x ^ 4 + ax ^ 3 + BX ^ 2 + ax + 1 = 0, and find the minimum value of a ^ 2 + B ^ 2
Why x + 1 / x > 2 or

Let x + 1 / x = t, when x is not equal to 0, divide by X, get x ^ 2 + ax + BX + A / x + 1 / x ^ 2 = 0, get T ^ 2 + at + B-2 = 0. Here we need to know the range of T, X + 1 / x = t, t is greater than or equal to 2, or less than or equal to - 2. There is an equal sign! If we don't understand it, we can look up the inequality of two knowledge means.. here, positive integer a + B is always greater than or equal to ab under the root sign

A and B are opposite to each other. The absolute value of M is 3. Find the value of 9 (a + b) + M

A and B are opposite numbers
So a + B = 0
|m|=3
So m = ± 3
9(a+b)+m
=m
=±3

Let f (x) = ax & # 178; - | x | + 2a-1 (a is a real constant)
Let the minimum value of F (x) in the interval [1,2] be g (a), and find the expression of G (a)

A:
1）
a=0,f(x)=x²-1
y=|f(x)|=|x²-1|
-1

If a + \ A-1 \ = 1 holds the value range of real number a, it is the sign of absolute value``

|a-1|=1-a
A-1 and 1-A are opposite numbers
So A-1

We know the quadratic functions Y1 and Y2 of X, where the image opening of Y1 is downward and intersects with X axis at points a (- 2,0) and B (4,0)
We know the quadratic functions Y1 and Y2 of X, where the image opening of Y1 is downward, intersects the X axis at a (- 2,0) and B (4,0), and the symmetry axis is parallel to the Y axis,
The distance between the vertex and B is 5, and y2 = - 4 / 9x square - 16 / 9x + 2 / 9
Finding the functional expression of quadratic function Y1

Let Y1 = a (x-x1) (x-x2) (a < 0)
According to the meaning of the title, there are
y1=a(x+2)(x-4)
Intersection of Y 1 and X axis at a (- 2,0) and B (4,0)
The axis of symmetry is x = 1
Let vertex coordinates be (1, y)
∵ the distance between vertex and B is 5 ∵ according to Pythagorean theorem, y = 4
The vertex coordinates are (1,4)
Substituting (1,4) into Y1 = a (x + 2) (x-4), we get a = - 4 / 9
∴y1=a(x+2)(x-4)=-4/9(x+2)(x-4)=-4/9x^2-8/9x+32/9