Given the function f (x) = log2 (x + 1), if the sequence - 1, f (A1), f (A2) , f (an), 2n + 1 (n is a positive integer) into the arithmetic sequence, find the general term of an

Given the function f (x) = log2 (x + 1), if the sequence - 1, f (A1), f (A2) , f (an), 2n + 1 (n is a positive integer) into the arithmetic sequence, find the general term of an

Let the tolerance of a given sequence be D, then 2n + 1 = - 1 + (n + 1) d,
The solution is d = 2, f (an) = - 1 + nd = 2N-1
Furthermore, f (an) = log2 (an + 1), х log2 (an + 1) = 2N-1
　　∴an=2^(2n-1)-1.

Decimal addition and subtraction, column vertical get results, found that after the decimal point is 0. In the vertical, you want to cross out the 0 after the decimal point?
I know. I want to know if I want to cross out the zero after the decimal point

No, in the real exam, the vertical style doesn't need to be written on the paper, just on the calculus paper

The circumference of a circle is 376.8 decimeters. How many square decimeters is the area of the circle?

Radius 376.8 △ 3.14 △ 2 = 60 decimeters
Area: 3.14 × 60 × 60 = 11304 square decimeters

As shown in the figure, in p-abcd, PA = AB = a, point E is on edge PC. (1) ask where point E is, PA ‖ plane EBD, and prove it; (2) find the cosine value of dihedral angle c-pa-b

(1) When e is the midpoint of PC, PA ∩ plane EBD connects AC and EO, and AC ∩ BD = O ∵ quadrilateral ABCD is a square, O is the midpoint of AC, e is the midpoint, OE is the median line of △ ACP, PA ⊄ plane EBD, EO ⊂ plane EBD ⊂ PA ∥ plane EBD (2) takes the midpoint F of PA, connects of, BF, ∵ P

If you know the chord length and chord height of the sector, can you calculate the arc length of the sector by geometric method?

Let the chord length be m and the arc height be H,
The sector radius can be obtained by the formula
R＝(4h²+m²)/(8h)
Then, with sina = m / (2R), the sector angle a can be obtained with a calculator,
In this way, the arc length of a sector (actually an arch) can be obtained
S＝2aRπ/360

Observe 2 = 1x2, 2 + 4 = 2x3, 2 + 4 + 6 = 3x4. Guess 2 + 4 + 6 +. + 2n=

As can be seen from the previous formula, there are several such adjacent even numbers added together, which can be expressed as several times several plus one. For example, the first formula 2 = 1x2, and the second formula is two even numbers added together, which can be expressed as 2x3, so 2 + 4 + 6 +. + 2n, which means that there are n such numbers added together, can be expressed as NX (n + 1), written as n (n + 1) or n ^ 2 + n. this is to use the multiplication allocation rate to open the brackets, Both indicate the same result
N (n + 1) or N & # 178; + n
Is that clear?

Which season do you like best? What's the reason? Please write a 60 to 80 word essay in English according to your own situation and imagination

My favorite season is fall.In fall,I can enjoy the good havest.Plenty of fruit and a great variety of vegetables bring me a delicious fall.At the same time,the cool weather makes outdoor activities an...

A second grade mathematics inverse proportion function problem, urgent, everyone help ~~~~~~~~~~~~~~~~~~~~~~~~ thank you!
If one of the intersection coordinates of the image of the positive scale function y2x and the image of the inverse scale function YK / X is (2, m), then M=______ ,k=_______ The other intersection coordinates are:
How to find the coordinates of the intersection point of inverse proportion function and positive proportion function or primary function

y=2x
y=k/x
2x=k/x
2x^2=k
k=8
m=2*2=4
2x^2=8
x^2=4
X = 2 or x = - 2
y=2*(-2)=-4
So the coordinates of the other intersection point are: (- 2, - 4)

A cuboid is 10 cm long, 8 cm wide and 5 cm high. Cut it into two cuboids. What is the maximum sum of the surface areas of the two cuboids

(10×8+10×5+8×5)×2+10×8
=(80+50+40)×2+80
=340+80
=420

Sin (π / 4 + x) = 3 / 5, find sin 2x

Cos (π / 4 + x) = cos π / 4cosx sin π / 4sinx = (1 / √ 2) (cosx SiNx) = 3 / 5, cosx SiNx = 3 √ 2 / 5, the square of both sides, cos & # 178; &# 8206; X + Sin & # 178; &# 8206; x-2cos & # 8206; xsinx = 18 / 25, 1-sin2x = 18 / 25, sin2x = 7 / 18, it is not easy to type,