Virtual module length, how to find ah. Use mathematical expressions bar

Virtual module length, how to find ah. Use mathematical expressions bar

For example, in the example you gave, you must first multiply the denominator of the conjugate (1-I) into reality. Then you get the length of the circuit chip (square root of 2) / 2 with * (1 - Ⅰ) / (1 +) (1 - Ⅰ) = 1 / 1 + 1 = 1 / 2 + / 2

Finding the value of an expression
five
How much is this?
r=0
It seems that the answer is 112 ~ I don't know what the situation is 0 - 0

Original formula = 0x1 + 1x2 + 2x3 + 3x4 + 4x5 + 5x6 = 2 + 6 + 12 + 20 + 30 = 70
If r = 6, the result is 112

Find a mathematical expression
A variable a represents 1,2,3, equal number, a constant 46, how to get the expression of 1,46,92138184, equal number

n=1,a1=1 n≥2,an=46(n-1)

The number of intersections between the square of y = x - ax + A-2 and the coordinate axis is ()
Please tell me why, thank you!

There is no sign on the keyboard, so use triangle instead of triangle = b2-4 * a * C = A2-4 * 1 * (A-2) = A2-4 * a + 8. In the formula A2-4 * a + 8, use the Vader's theorem again to get triangle = - 160, so A2-4 * a + 8 is always greater than 0, that is, the number of intersections between y = x2-ax + A-2 and the coordinate axis is 2

S=2πr²+2πrh
V=2πrh
These two are s, R, h are unknowns. Which of them is a quadratic function······
The second V is also unknown

First
Because the quadratic function refers to the polynomial function of which the highest degree of the unknown is quadratic. The quadratic function can be expressed as f (x) = ax ^ 2 + BX + C (a is not 0)

How to write the mathematical expression of n-th power with root sign in C language

#Include # include void main() {int i, J; double x; scanf (% d ", & J); / / enter the number of square root scanf (% F", & x); / / enter the number of square root for (I = 0; I

On the sum formula of the first n terms of equal difference
The sum formula of the first n terms of the arithmetic sequence {a (n)} is
S(n)={n[a(1)+a(n)]}/2=na(1)+[n(n-1)]d/2=na(n)-[n(n-1)]d/2
All in parentheses are subscripts
Here I would like to ask the second and third formula under what circumstances? Why do I use the first formula for the question? The answer is the same as the standard answer, the second and third formula (that is, s (n) = Na (1) + [n (n-1)] d / 2 = Na (n) - [n (n-1)] d / 2) is wrong, and the answers calculated by the second and third formulas are the same
Take the following question for example
If {a (n)} is an arithmetic sequence and a (2) = 4 / 5, a (5) = 8 / 5, then s (6)=___________
Using the first formula s (n) = {n [a (1) + a (n)]} / 2, the result is 36 / 5, which is the same as the standard answer
But using the second and third formula, the answer is 108 / 5
What's the matter, please?

It's all the same. It's all 36 / 5
It's your own miscalculation!
Using the second formula:
S（6）=6*（8/15）+6*5*（4/15）/2
=16/5+4
=36/5
Using the third formula:
S（6）=6*（28/15）-6*5*（4/15）/2
=56/5-4
=36/5

Derivation of the product formula of the first n terms of arithmetic sequence

Derivation of the sum of the first n terms of the arithmetic sequence:
Sn = a1 + A2 +. An-1 + an
Sn=an+an-1+.a2+a1
By adding the two formulas, 2Sn = (a1 + an) + (A2 + an-1) + (an + A1)
=n(a1+an)
So Sn = [n (a1 + an)] / 2
If it is known that the first term of the arithmetic sequence is A1, the tolerance is D, and the number of terms is n, then an = a1 + (n-1) d is substituted into formula (1)
Sn=na1+ [n(n+1)d]/2(II)
No,
Product formula of the first n terms of arithmetic sequence

Given A1 = 1, a (n) - 3A (n) &; a (n-1) = 0, find the general formula of a (n)

If a (2) = 3A (2) a (1), then a (2) = 3A (2), then a (2) = 0
1 n=1
a(n)={
0 n>1

Given A1 = 1, a (n) - 3A (n)? A (n-1) = 0, find the general formula of a (n)
Given a (1) = 1, a (n) - 3A (n) &; a (n-1) - A (n-1) = 0, the general term formula of a (n) is obtained
It's best to write the process

Because a (n) - 3A (n) &; a (n-1) - A (n-1) = 0, so a (n-1) = a (n) / (1 + 3A (n)), so 1 / a (n-1) = 1 / a (n) + 3, so 1 / a (n-1) - 1 / a (n) = 3, so 1 / a (n) is an arithmetic sequence with 1 / A2 as the first term - 3 as the tolerance