In (), fill in the appropriate length unit 1 () - 1 () = 9 1 () - 1 () = 99 1 () - 1 () = 999

In (), fill in the appropriate length unit 1 () - 1 () = 9 1 () - 1 () = 99 1 () - 1 () = 999

1 (m) - 9 (DM) = 1 (DM) 1m-9dm = 1dm 1m-9dm = 1dm or 1dm-9cm = 1cm 1 (m) - 9 (DM) = 1 (DM) 1 (DM) - 9 (CM) = 1 (CM)

If the focal length of the ellipse is equal to the distance between the vertex of the major axis and the minor axis, calculate the eccentricity E

The distance between the vertex of major axis and minor axis = √ (a ^ 2 + B ^ 2) focal length = 2C. So: A ^ 2 + B ^ 2 = 4C ^ 2. According to the elliptic property: A ^ 2 = B ^ 2 + C ^ 2, there are two simultaneous formulas: 4C ^ 2 = 2A ^ 2-C ^ 2, that is 5C ^ 2 = 2A ^ 2, so e = C / a = (√ 10) / 5. This is the correct solution

Put two equal squares together to form a rectangle. The perimeter of the rectangle is 21 decimeters, and its area is______ Square decimeter

Let the width of a rectangle be x decimeter. From the meaning of the title, we can get: (x + 2x) × 2 = 21, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 6x = 21, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

What is the relationship between XY + YZ + XZ and the cube root of the square of three times [XYZ]

If x, y and Z are all greater than 0, according to the geometric mean inequality,
(XY + YZ + XZ) / 3 > = [XY * YZ * XZ] cube root = [XYZ] square cube root,
So XY + YZ + XZ > = 3 times the cube root of the square of [XYZ]

The ellipse x ^ 2 / 25 + y ^ 2 / 16 = 1 has a moving point P and F1F2 is the two focal points. The trajectory equation of the center of gravity g of △ pf1f2 is obtained

G(x,y) P(x0,y0)
x=x0/3
y=y0/3
x0=3x y0=3y
x0^2/25+y0^2/16=1
Trajectory equation 9x ^ 2 / 25 + 9y ^ 2 / 16 = 1

If a divided by B equals the remainder e of C, where B is the smallest prime number and C is the smallest composite number, then the remainder e equals? A equals?

The smallest prime number is 2, so B = 2, that is, divisor equals 2
The remainder must be an integer less than the divisor, so e = 1
The smallest composite number is 4, so C = 4, that is, quotient = 4
The divisor is equal to the quotient multiplier divisor plus the remainder. The divisor = 9, so a = 9

It is proved that the function f (x) = x + 1 x is a decreasing function on (0,1)

It is proved that: ∵ f (x) = x + 1X, ∵ f '(x) = 1-1x2 = x2 − 1x2, and ∵ x ∈ (0,1), ∵ 0 ＜ x2 ＜ 1, ∵ f' (x) ＜ 0, ∵ function f (x) = x + 1x is a decreasing function on (0,1)

Given the function f (x) = [x + 1], find the value of F (3.2) f (- 5.1) f (- 4.8) f (7.2)
Given f (x) = [x + 1], (2) find the value of F (3.2) f (- 5.1) f (- 4.8) f (7.2)

X plus 1 and rounding
4,-5,-4,8

Fill in the brackets with different prime numbers 48305 = 4 × () + 8 × () + 3 × () + 5 × ()
Hurry up, it's urgent!

10000 1000 100 1

Let the probability density of random variable X be f (x) = {C / x ^ 3, x > 1; 0, X