(- 1 / 6) cube × (- 6 / 7) cube

(- 1 / 6) cube × (- 6 / 7) cube

(- 1 / 6) cube × (- 6 / 7) cube
=Cube of [(- 1 / 6) × (- 6 / 7)]
=Cube of 1
=1

Given that the first n terms and Sn of sequence {an} satisfy log2 (Sn + 1) = n + 1, the general term formula of sequence {an} is obtained

From the known Sn + 1 = 2N-1, we get Sn = 2n + 1-1, so when n = 1, A1 = S1 = 3; when n ≥ 2, an = sn-sn-1 = 2n, and A1 = 3 does not conform to an = 2n, so the answer is an = 3 (n = 1) 2n (n ≥ 2)

A taxi charging standard is: starting price (within 1 km) 3 yuan, more than 1 km part per km 2 yuan, more than 3 km part per km 1,4 yuan, Wang
The charging standard of a taxi is: the starting price (within 1 kilometer) is 3 yuan, the part more than 1 kilometer is 2 yuan per kilometer, and the part more than 3 kilometers is 1 or 4 yuan per kilometer. Mr. Wang takes a taxi to a school 12 kilometers away for a meeting. How much is the fare when he arrives at the school?

3+2X（3-1）+1.4X（12-3）
=3+4+12.6
=19.6 yuan

PA ⊥ rectangle ABCD plane, Mn are the midpoint of ABPC
PA is perpendicular to the plane of the rectangle ABCD. N is the midpoint of ABPC to verify (1) Mn / / planar pad. (2) The PCD of Mn ⊥ plane is proved if the angle PDA of Mn vertical CD (3) is 45 degrees.

Take PD midpoint e, connect AE, NE
1. ∵ N and E are the midpoint of PC and PD
∴NE∥CD∥AM,NE=CD/2=AB/2
And M is the midpoint of ab
∴NE=AM
The amne is a parallelogram
∴AE∥MN
∵ AE ∈ planar pad
Ψ Mn ‖ planar pad
2. ∵ PA ⊥ plane ABCD
∴PA⊥CD
ABCD is a rectangle
∴CD⊥AD
⊥ CD ⊥ planar pad
∴CD⊥AE
∵MN∥AE
∴MN⊥CD
3.∵∠PDA=45°
The pad is an isosceles right triangle
∵ e is the PD midpoint
∴AE⊥PD
Again AE ⊥ CD
⊥ AE ⊥ planar PCD
⊥ Mn ⊥ plane PCD

I know that the negative power of a number is the reciprocal of its power. What about the negative fractional power?
There's also a number to the second power minus twice that. How do you calculate that?
For example, the second power of X - 2x
Halo, I'm talking about the negative fractional power of a number, such as the - 2 / 5 power of 7

If the power of negative fraction is negative fraction, the power of negative fraction is the reciprocal of its power, the other power of negative fraction will be calculated. The power of fraction has no absolute relationship with positive and negative
For example, if the number is 4, the second power of 4 is 16, and its double is 8, 16-8 = 8
The second power of x-2x = x (X-2)

A taxi company has 100 taxis, and the average daily gasoline cost of each taxi is 80 yuan. In order to reduce environmental pollution, the market introduces a device called "CNG" to convert gasoline to natural gas, and the price of each taxi is 4000 yuan. After the company refits some vehicles for the first time, it calculates that the daily fuel cost of the refitted vehicles accounts for the daily fuel cost of the remaining unmodified vehicles Q: (1) how many taxis has the company refitted? How much is the average daily fuel cost of each taxi after modification lower than that before modification? (2) If the company refits all taxis at one time, how many days can it recover the cost from the saved fuel cost?

(1) Suppose the company refits y taxis for the first time, and the fuel cost of each taxi after refitting is reduced by a percentage of X. according to the meaning of the problem, the equations are as follows: 80 (1 − x) y = 320 × 80 (100 − y) 2Y × 80 (1 − x) = 25 × 80 (100 − 2Y). The solution is x = 25 = 40%, y = 20 The daily fuel cost of the car is 40% lower than that before modification; (2) if the cost can be recovered in M days after one-time modification, then 100 × 80 × 40% × M = 4000 × 100, so m = 125 (days) a: if the company refits all taxis at one time, the cost can be recovered from the saved fuel cost in 125 days

As shown in the figure, given ad = 4, CD = 3, ∠ ADC = 90 °, ab = 13, BC = 12, calculate the area of quadrilateral ABCD

As shown in the figure, connect AC, because ad = 4, CD = 3, ∠ ADC = 90 °, so AC = 33 + 42 = 5, △ ACD area = 6. In △ ABC, because AC = 5, BC = 12, ab = 13, ｜ ac2 + BC2 = AB2, that is, △ ABC is a right triangle, and ∠ ACB = 90 °, so right angle △ ABC area = 30, so quadrilateral ABCD area = 30-6 = 24

Master Wang planned to finish the work in five hours, and as a result, he finished the work in four hours

120% quarter / fifth (set work to 1)

Party A and Party B process parts in 20 days, Party A processes 45 parts per day, and finally 300 more than Party B?

45-300 / 20 = 30 pieces --- B processes every day

The area of the largest circle drawn in a square is 28.26 square centimeters

28.26÷3.14=9
9=3×3
So the radius of the circle is three centimeters
The side length of a square is 2 × 3 = 6cm
Square area = 6 × 6 = 36 square centimeter