Given the random variable x ~ B (6,1 / 2), then d (2x + 4) is equal to? Correction: B (6,1 / 2),

Given the random variable x ~ B (6,1 / 2), then d (2x + 4) is equal to? Correction: B (6,1 / 2),

B(6,1/2),n=6,p=1/2,DX=np(1-p)=3/2,D（2X+4）=2^2DX=6

Let a = {x | x > 1}, B = {x | x (X-2)

x(x-2)

Let a = {x | 1 / X1 / 3}, then a ∩ B is equal to

Simplification 1 part a
A={x|1/x

If 6 / (x + 1) (X-2) = ax + B / x + 1 + C / X-2, what are the values of a, B and C?

Ax+B/(x+1)+C/(x-2)=Ax(x+1)(x-2)/(x+1)(x-2)+B(x-2)/(x+1)(x-2)+C(x+1)/(x+1)(x-2)={Ax(x^2-x-2)+Bx-2B+cx+c}/(x+1)(x-2)Ax(x^2-x-2)+Bx-2B+cx+c=6Bx-2B+cx+c=6A=0B+C=0C-2B=6B=-2 C=2

Calculate the triple integral ∫ ∫ ∫ zdxdydz, Ω, the closed region bounded by x ^ 2 + y ^ 2 + Z ^ 2 = 1 and z = root (x ^ 2 + y ^ 2)
Cylindrical coordinate transformation

∫∫∫ zdxdydz = ∫ D θ∫ RDR ∫ ZDZ (for cylindrical coordinate transformation)
=2π∫(1/2)[(1-r^2)-r^2]rdr
=π∫(r-2r^3)dr
=π(1/8)
=π/8.

120 kilometers per hour is equivalent to several meters per second

1m / S = 3.6km/h, the conversion method is time and time, length and length, 120 / 3 /. 6 = 33.3333m/s

1 + 3 = 4 = 22, 1 + 3 + 5 = 9 = 32, 1 + 3 + 5 + 7 = 16 = 42, 1 + 3 + 5 + 7 + 9 + 11 = 36 = 62, 1 + 3 + 5 + 7 + 9 + +97+99+101=______ =______ ．

1+3+5+7+9+… +97 + 99 + 101 = (2601) = (512), so the answer is: 2601512

Is it possible to cut a cylinder into an isosceles trapezoid, partial ellipse or triangle with a plane?

Yes,
When the plane intersects the two ground surfaces of the cylinder, if the plane is not perpendicular to the two bottom surfaces, the section is an isosceles trapezoid, and when it is perpendicular, it is a rectangle or square
When a plane intersects one bottom of a cylinder and has only one intersection with another ground, the cross section is a triangle
When the plane intersects with each side of the cylinder, if it is not parallel to the bottom, it is an ellipse; if it is parallel, it is a circle
You can find an actual cylinder to cut and see

The ratio of length to width of a rectangle is 5:3, and the ratio of length to width is 12 cm. What is the area of the rectangle?

Let the length of the rectangle be 5x and the width be 3x
5x-3x=12
2x=12
x=6
The length of the rectangle is 5x = 5 * 6 = 30cm,
Width: 3x = 3 * 6 = 18cm
Area of rectangle: 18 * 30 = 540cm ^ 2

If 4x ^ 2-4x + 9y ^ 2-12y + 5 = 0, find (x-3y) ^ 2 - (x + 3Y) ^ 2

4X ^ 2-4x + 9y ^ 2-12y + 5 = 04x ^ 2-4x + 1 + 9y ^ 2-12y + 4 = 0 (2x-1) ^ 2 + (3y-2) ^ 2 = 0, so 2x-1 = 0x = 1 / 23y-2 = 0y = 2 / 3 (x-3y) ^ 2 - (x + 3Y) ^ 2 = (x-3y + X + 3Y) (x-3y-x-3y) = 2x * (- 6y) = - 12xy = - 12 * 1 / 2 * 2 / 3 = - 4