Tell me about this math problem

According to the conditional region, y -x+3 and y x+1 are deduced (the other two boundaries y=x-3 and y=-x-1 correspond to x and y are both less than 0).

The intersection of the two lines (1,2) should be the extreme point of the function z=xa+y b (or there is an extreme value of z on one of the boundaries), i.e., 1 a+2 b 5;

The transformation yields b 2a (5a-1)(5a-1>0);

Let a+8b = m a+8*2a (5a-1), the value of m be constrained, and the formula is: 5a + (15-5m) a + m 0;①

Since z has an extremum, then the real number a>0 must exist, so (15-5m) -4*5*m 0, i.e., 5m -34m+45 0;....②

To solve the unary quadratic inequality with respect to m, we get: m 9 5 or m 5;

When m 9 5, the root a is found by the equation is negative (unconditional), so only m 5 can be taken

So m 5;The corresponding m is the minimum value, a - (15-5m) (2*5) = 1, b 2a (5a-1) = 1 2 (or b (m-a) 8 = 1 2);

If a<1, b<1 2, then the maximum value of the objective function z must be greater than 5 in the permissible value range of x and y;

From the question, we can know that x is equal to -3, less than or equal to 3; y is greater than or equal to -2, less than or equal to 2So the maximum value of z is 3 a+2 b = 5 (which can be obtained by using the mean inequality) The root number ab is greater than or equal to 2/5 times the root number 6, so the minimum value of a+8b is 16 times the root number 3 I hope it can help you!

a+b)=a 2+b 2+ab+ba=a+b, because a 2=a b 2=b

So ab+ba=0

a 2 = a so the eigenvalue of a has.

b 2-b=0 =>b=0 or posture b=1 (b is the eigenvalue of a) ab+ba=0 left multiplication a.

ab+aba=0

ab(e+a)=0

Because the special year of a can only be selected between 0 and 1, the characteristic value of a+e can only be selected between 1 and 2.

So the a+e determinant is not equal to 0

Then a+e is irreversible, which means that there are n uncorrelated vectors.

That is to say, ab has n basic solution systems (because ab(e+a)=0, e+a can be regarded as the solution of ab's homogeneous equation).

That is, the rank of ab is 0

Then ab can only be 0

begged Wang Ming to walk for an hour, because Zhang Lan didn't walk for an hour).

Answer: Zhang Lan met an hour after departure.

Wang Ming goes one hour first, and the journey of 1 hour should be subtracted, and then calculated:

Hours after Zhang Lan set off to meet.

[Use ratio answers].

Let the male worker x and the female worker y, the total amount of money = 12(x+y) = 20y

There is 12x=(20-12)y

12x=8y

y=3/2*x

If only male workers are allocated, each person will receive an average of 20y x = 20 3 2*x x = 30 pieces.

Suppose the total number of boxes of soap is 1, then.

1. When men and women share the time, each person is divided into 12 pieces, and the number of male and female workers = the total number of soaps distributed by each person = 1 12;

2. When only female workers are divided, each person gets 20 pieces, indicating that the number of female workers = the total number of soaps The number of blocks divided by each female worker = 1 20;

3. The number of male workers = the total number of workers - the number of female workers = 1 12-1 20 = 1 30;

4. Therefore, if only male workers are distributed, the number of blocks that male workers get = total number of soaps Number of male workers = 1 (1 30) = 30 pieces.

There are x male employees and y female employees.

Then 12(x+y)=20y

12x=8y

x：y=2:3

The total amount of soap remains the same, so the ratio of the number of people is inversely proportional to the number of blocks allocated, so only male workers are distributed, and each person gets the female worker: 3 2 points: 20 3 2 = 30 pieces.

Or: 1 (1 12-1 20) = 30 blocks.

If there are x male workers and y female workers, only male workers will be distributed, and each person can be assigned to block A on average, and 12 (x+y) = 20y = ax can be obtained according to the title

So 12x=8y,y=

ax=20*

a=30 is only allocated to male workers, and each person can get an average of 30 yuan.

The denominator is (3 2*2) 3-(3 2*4) 3+(3 2*6) 3-(3 2*8) 3+(3 2*10) 3-(3 2*12) 3=(3 2) 3*numerator.

So the result is a, 8 27

It's not easy to write, the numerator proposes the cube of common factor 2: 2 3 (1-2 3+3 3-4 3+5 3-6 3), and the denominator proposes the cube of common factor 3: 3 3 (1-2 3+3 3-4 3+5 3-6 3), divide the minute, do not count in parentheses, it is the same at first glance, approximate the minute, the remaining 2 3 3 3 = 8 27, choose a

1. This question is not large, just calculate it directly.

2. The numerator puts forward the 3rd power of 2, and the denominator puts the 3rd power of 3, and the rest is the same, so the result is 8 27

(1) Solution: Because the angle AOB = angle COD = 90 degrees.

Angle AOD = Angle AOC + Angle COD - Angle 1 = 180 - Angle 1 So Angle AOD + Angle 1 = 180 degrees.

2) Solution: Because the angle aod = angle 2 + angle 3 + angle eof angle aod = 180 - angle 1

Angle eof = 100 degrees.

So angle 1 + angle 2 + angle 3 = 80 degrees.

3) Solution: Let the angle of the bisector of the angle eoc and the angle fod be x, so x=1 2 (angle eoc + angle cof + angle fod) because the angle fod = angle 3

Angular cof = angular cod - angular fod

Angular cod = 90 degrees.

So angular cof=90-angular 3

Because the angle eoc = angle aob-angle 1-angle 2

Angle AOB = 90 degrees.

So the angle eoc = 90 - angle 1 - angle 2

So x=1 2[180-(angle1+angle2+angle3)] because angle1 + angle2+angle3=80 degrees.

So x=50 degrees.

Therefore, the angle between the angle EOC and the bisector of the angle FOD will not change, and the angle is 50 degrees.