A division of the same base power (3) mathematical problem When a positive number is written to the nth power of a × 10 by means of scientific counting method, there should be____ ≤a＜____ When the speed of light is written as a × 10N km / s, n=_____ When we write n to the power of M / s=____ When the result of (1.5 × 10 to the second power) × (8.4 × 10 to the fifth power) is written in the form of a × 10 to the nth power, n=_____ .

A division of the same base power (3) mathematical problem When a positive number is written to the nth power of a × 10 by means of scientific counting method, there should be____ ≤a＜____ When the speed of light is written as a × 10N km / s, n=_____ When we write n to the power of M / s=____ When the result of (1.5 × 10 to the second power) × (8.4 × 10 to the fifth power) is written in the form of a × 10 to the nth power, n=_____ .

The first empty 1; the second empty 10; the third empty 5; the fourth empty 8; the fifth empty-2
Given the distance d from point a (a, 6) to line 3x-4y = 2 as the following values, find the value of A. (1) d = 4 (2) d > 4
How to solve this problem
The formula is: the distance from point (X & # 8321;, Y & # 8321;) to straight line ax + by + C = 0 is d = ︱ ax & # 8321; + by & # 8321; + C / √ (A & # 178; + B & # 178;) and the general formula is 3x-4y-2 = 0, so the distance from point a (a, 6) to straight line is d = ︱ 3a-4 × 6-2 / √ (3 & # 178)
The distance from a point to a line. Substituting a and D into solvable.
3a-4 and negative 4a-4
3A-4-(-4A-4)=7A
A>0 --> 3A-4>(-4A-4)
A 3A-4 3A-4=(-4A-4)
By nine o'clock in the evening
In a cylindrical glass with a bottom diameter of 4 decimeters, there is a plumb with a bottom diameter of 2 decimeters and a height of 3 decimeters. After taking out the plumb, how many centimeters will the water surface in the glass drop
Plumb = cone I know the answer is 2. Analysis of 5cm formula
The volume of the plumb is equal to the volume of the water surface falling. The volume of the plumb is a cone
3.14 × (2 ／ 2) × (2 ／ 2) × 3 ／ 3 ／ [3.14 × (4 ／ 2) × (4 ／ 2)] = 0.25 decimeter = 2.5cm
When the volume of lead is 1 / 3 * π * 10 * 10 * 30 = 1000 π, the height of water decreases to 1000 π / (π * 20 * 20) = 2.5cm
Do you want a process?
If not, the answer is 0.25 decimeter
First of all, how high is the glass?
If it is higher than 3 decimeters, then the descending height is 2.5cm
If it's less than 3 decimeters, it's a little more complicated...
The typical logic of this topic is not strict, and I deeply despise the teachers and my youth
Given that the distance between the point (1, - 2) and the line 3x-4y + a = 0 is 6, find the value of A
L3x1 + 4x2 + Al / √ (the square of 3 + the square of 4) = 6
l11+al/5=6
l11+al=30
a+11=±30
A = 19 or a = - 41
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Using the formula of distance from point to line
Bring in the coordinates. 3 (1) - 4 (- 2) + a = 6, so a = - 5. 3 (1) - 4 (- 2) + a = 6, so a = - 5
Given that a is greater than 4 (1) compare the square of a with the size of 4A (2) compare the size of AB with 4A
analysis
A>4
a²-4a=(a-2)²-4
Because a > 4
So (A-2) & # - 4 > 0
a²>4a
Where is that B
9:00 connection math problem
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Nine o'clock connection
requirement:
Only three turns, that is to say, four straight lines, are allowed to be made in one stroke
If you mark nine dots from left to right and from top to bottom
This should be done as follows:
1-->5-->9
-->8 -- > 7 (continue to move forward for a distance, which is equal to the distance between two adjacent points in the horizontal direction)
-->4 -- > 2 (continue to move forward for a distance, which is equal to the distance between two adjacent points in the diagonal direction)
-->3-->6-->9
You want to get the answer is daydreaming, I can only tell you this question, even the teacher of Beijing NO.4 middle school can not answer
I'll number each point first
1 2 3
4 5 6
7 8 9
The sequence is as follows: 159 fold to 87 and extend, fold to 42 and extend, fold to 36
Don't limit yourself to the nine points. The topic doesn't have to be in any scope, does it?
The next three connect with the upper two, extend all the way, turn to the left column, the next one goes through the middle two connect with the upper three, extend, turn to the middle three to the lower two, complete. Thank you for the bonus
The parametric equation of a circle is known as x = 2cos, y = 2Sin. If the circle passes through a point (m, 1), find m, and find the maximum distance between the point on the circle and the line 3x + 4Y + 5 = 0
[the minimum distance from a point on a circle to a straight line is D-R, and the maximum distance is d + R (D is the distance from the center of the circle to a straight line, R is the radius of the circle)] ∵ the parameter equation of the circle is x = 2cos θ, y = 2Sin θ, and the sum of the two sides is x ^ 2 + y ^ 2 = 4 [cos ^ 2 (θ) + sin ^ 2 (θ)]
How big is 4A
210*297mm
It's A4, right
On the division of power
When bacteria propagate, a bacterium splits into two. After n times of division, the number of a bacterium becomes to the nth power of 2. There is a kind of bacteria with fast classification speed, which splits one every 15 minutes. If there are 1000 such bacteria now, how many such bacteria are there after 60 minutes? How many times is the number after 2 hours?
60÷15=4
1000×2^4 = 16000
120÷15=8
1000×2^8 = 256000
256000 ÷ 16000 = 16
A: after 60 minutes, there are 16000 such bacteria? The number after 2 hours is 16 times that after 1 hour
One
16000 16
Split every 15 minutes, split every 60 minutes, split every four times in an hour, split every two hours, split every eight times in 120 minutes
A bacterium splits n times into 2 ^ n
1000 bacteria divided four times to 1000 x2 ^ 4 = 16000
In the same way
1000 bacteria divided 8 times into 1000x2 ^ 8 = 256000
256000÷ 16000=16
Another 2 ^ n to remember
Expand n from 1 to 10
Split every 15 minutes, split every 60 minutes, split every four times in an hour, split every two hours, split every eight times in 120 minutes
A bacterium splits n times into 2 ^ n
1000 bacteria divided four times to 1000 x2 ^ 4 = 16000
In the same way
1000 bacteria divided 8 times into 1000x2 ^ 8 = 256000
256000÷ 16000=16
Another 2 ^ n to remember
N is 1-10
2, 4, 8, 16, 32, 64128256, 512, 1024