Rush math answers, rush math answers

There are 6 cases, and 2 of the conditions are met, so the probability is 1 3

The first course: 1) the probability that all 3 pieces are first-class:

p1=（50/80）*（49/79）*（48/78）=245/1027

2) 2 pieces are first-class products and 1 piece is second-class products

p2=(50/80)*(49/79)*(20/78)*3=1225/4108

3) The probability of one piece each of the first, second, and third class.

p3=(50/80)*(20/79)*(10/80）*6=125/6162

The second way: the basic events are: (upper, middle, lower); (upper, lower, middle); (middle, top, bottom);

Middle, bottom, top); (bottom, top, middle); (lower, middle, upper) a total of 6, meet the requirements of (upper, middle, lower) and (lower, middle, upper) a total of 2.

So the probability is p=2 6=1 3

Set the strings c(a,b),d(c,d) m(

Then the pure bucket punch has 2x=a+c, 2y=b+d

a2+b2/2=1

c2+d2/2=1

Subtract the two formulas. 2x(a-c)=-y(b-d)

cd slope k=(a-c) pin loss(b-d)=-2x y (3)cd point(2,1) k=(y-1) do j(x-2) (4)3)=(4).

y(y-1)=-2x(x-2)

a^2=52/5+1/b^2=1

b^2=5/3

x^2/5+y^2/(5/3)=1

Let the orange ridge rent a(x1,y1)b(x2,y2)x1-x2)(-1 2*2)+3(y1-y2)2y=0 slope circle trillion k=(y1-y2) (x1-x2)=1 (6y)=(y-0) (1 wild liter2-(-1)).

y^2=1/12

k^2=1/3

x1+x2=-1

y1+y2=-2

ab = 2 root number 3

1. The second year of high school is the average of the three grades; The sample size is also the average of the three grades; i.e. 360 3 = 120 (person).

So the third year of high school is 360 100 120 140 (people);

2. The probability is: 1 2 * 1 2 * (1-1 2) * 3 = 3 8

First of all, it depends on how many options each student has

Participate in a group, 4 situations; Participate in two groups, 6 situations, so there are 10 situations in total.

Then 42 students were assigned to these 10 situations, and at least 11 students were in exactly the same situation

Hope it helps the landlord

Solution: From the problem, each person should participate in at least one group.

There are 42 students in the class, in four groups.

42 4 10 people. 2 people.

At least 10 students participate in the same extracurricular group.

,b=-1/2

ax+by)^2+(ay-bx)^2=(a^2+b^2)(x^2+y^2)=34

a=-3,b=7,c=-2

a-b) 2+(b-c) 2+(c-a) 2=3(a 2+b 2+c 2)-(a+b+c) 2When a+b+c=0 (there are multiple cases), the maximum value is 2008

<> the later draft, the state ode continues to be keyed, Zheng Jijin.

Such as a smile and a rampant dust, trying to destroy the sedan car.

<> watched Sun Xiao talk about serving the plan.

Please take a clear picture.

Let the common ratio be q, then there is.

a5=a3*q 2, q 2 >0, so a5 and a3 have the same name (either they are positive or negative), and the game laughs from a5+a3>0, knowing that a5 and a3 are both macro positive numbers.

a1*a5 = a3 2 = 4, so a3 = 2, from a3 + a5 = 8 a5 = 6;

Substituting the formula a5 = a3*q 2, q2 = 3

a13/a9 = q^4 = 9