Ask a math problem and I want to solve it in detail

In the first step, square both sides of the equation; In the second step, the two sides of the equation are simplified, and the final result is 1 cos squared -1 on the left and tan squared on the right. In the third step, both sides are multiplied by the square of cos, and then the term is shifted, so that the square of the isoidant sin + the square of cos = 1. So the scope of finding the original problem is to find the intersection of the solutions of the three equations -sin +sin >0; 3. Tan makes sense. You'll do it

First, verify that the equation is true. You can square both sides, and then calculate, and the result is that the equation is constant. Therefore, it is only necessary to start with the root number definition and the tana definition. That is.

1-sina)/(1+sina)>=0;

1+sina)/(1-sina)>=0;

a!=kpi+pi/2;

i.e. there is sina!=1;

sina!=-1;

A!=2kpi+pi/2;a!=2kpi+3/(2*pi);

There is a synthesis there. a!=KPI plus minus 2 pi;

Both sides are squared, and they are sorted out.

1-sin@）^2+(1+sin@)^2】/（1-sin^2@)=4tan@

remove parentheses; 4sin 2@ cos@=4tan@ when both sides are greater than 0, open square.

sin@\cos@=tan@

So, when 0<@<90, the original is true.

Summary. Hello, I will solve your doubts for you below, I hope it can help you.

To solve this problem, we must first understand a theorem! That is, when A2+B2>=2AB is taken as an equal sign if and only when A=B, that is, when the difference between A and B is zero, there is a maximum value of AB, then that is to say, when A+B is a fixed value, the smaller the difference between A and B, the greater the value of AB! Understand this theorem, and it will be solved!

Obviously, a+b=c+d, that is, the sum is a fixed value, then the smaller the difference, the larger its product, and all have cd>ab.

Verify that the root number A + the root number B root number C + the root number D square both sides at the same time A + B + 2 root number AB

I really hope I can help you, and I wish you happiness every day!

Ask a math question to detail the process you want.

Hello, I will solve your doubts for you below, I hope it can help you. To solve this problem, we must first understand a theorem! That is, when A2+B2>=2AB is taken as an equal sign if and only when A=B, that is, when the difference between A and B is zero, there is a maximum value of AB, then that is to say, when A+B is a fixed value, the smaller the difference between A and B, the greater the value of AB!

Understand this theorem, and lead luck is well solved! Obviously, A+B=C+D, that is, the sum is a fixed value, then the smaller the difference, the larger the product, and all have CD>AB. Verify that the root number A + the root number B root number C + the root number D square both sides at the same time A + B + 2 root number AB

What the hell. 4 k=-2, the square of x - the square of 3kxy-6xy-y, -3kxy-6xy should be 0, so k is -2. 7 2x square balance game + 3y + 7 = 8, the square of 6x is 3 times the square of 2x, 9y is also 3 times the square of 3y, multiply 3, get 6x square + 9y + 21 = 24, so the following formula = subtract 13 from both sides at the same time, so the answer is 11.

8 3x squared - 10-2y + 4x squared + mx squared, so''3x of the rough square + 4x of the square + mx of the square = 0, so the simplification of m should be -7, because 7 + (-7) is to let zero so the answer is d

It's not right.

What does that mean.

3.Because in quadrilateral ABCD, EFGH is the midpoint.

So GF is the triangular ACD median.

So GF is parallel to AC

The same can be said. HE is parallel to AC

So GF is parallel to HE

The same can be said. GH is parallel to FE

So the quadrilateral efgh is a parallelogram.

Question 1:

Because the quadrilateral ABCD is a parallelogram.

So δacd δcab

And because g and f are the midpoints of ad and cd respectively.

So in δACD, there are GFs parallel and equal to one-half AC while H, E are the midpoints of AB and CB respectively.

So in δacb, there is EH parallel and equal to one-half ac from above:

gf is parallel and equal to eh

So the quadrilateral fghe is a parallelogram.

You ask for fast, so do the first question first.

It has increased, because the decrease in those who make less money is only 15%, and the number of those who make more money has increased by 30%.

The total profit in the first quarter is: A + 2A + 40000 = 3A + 40000 The total profit in the second quarter is: A (1-15%) + 2A + 40000) (1 + 30%) =

Obviously, meta)

How old are you? Will the equation be? Classroom A can seat 5 times 10, which is 50 people.

Classroom B can seat 5 times 9, which is 45 people. Suppose A holds x training sessions and B conducts y sessions, then x+y=27,50x+45y=1290Then it's good to solve the equation.

If you don't understand the equation, you can think of it this way, assuming that 27 games are all run by B, then the number of people should be 27 times 45, that is, 1215 people, and the total number of training is 1290 people, then those extra people are because A has also done some training, and the calculation is that there are 75 more people, because A can sit 5 more people than B, so A has 75 divided by 5, that is, 15. Got it?

Similar to the problem of chickens and rabbits in the same cage.

Assuming that all 27 trainings are all classroom A, the number of trainees is 27*50=1350, more than 1350-1290=60

Reduce the training in classroom A once and increase the training in classroom B, the number of training will remain the same, but the number of people trained will be reduced5

60 5=12 So there are 12 sessions of training in Classroom B and 15 sessions of training in Classroom A.

If X times are trained in classroom A, then (27-x) times are trained in classroom B, 5x10x+9x(27-x)=1290, and the solution is x=15 and 27-x=12.

Classroom A is held x times, and classroom B is held 27-x times.

5x10xx+5x9x(27-x)=129050x+1215-45x=1290

5x=75x=15

That is, classroom A was held 15 times in the month.

Hope it helps!! ）

A total of x times of training were conducted in the classroom. Rule.

5×10)x+(5×9)×(27-x)=129050x+45×27-45x=1290

5x=1290-1215

5x=75x=15

Therefore, a total of 15 training sessions were held in Classroom A that month.

Let's say that A has been held x times, so B has held (27-x) times, and each time it is full, so classroom A has trained a total of 5 10 x people, and classroom B has trained a total of 5 9 (27-x) people, and the number of people adds up to a total of 1290 people, so the column formula 5 10 x + 5 9 (27-x) = 1290, just solve x. x=15

The mathematical model of this problem is very simple, each time point p moves to the left or right, it is equivalent to tossing a coin, throwing heads to the left and throwing tails to the right, this problem is equivalent to: tossing a coin several times, finding the probability that the number of heads and tails is the same.

First the number must be even, otherwise the positive and negative numbers cannot be equal, we assume that it is 2n times and its total probability is 2 (2n), where the number of heads n times is c(2n, n), so the probability of the same positive and negative (i.e., point p back to point q) is: c(2n, n) 2 (2n).

128 km.

The circumference of the lake is 1 kilometer 8 equal parts, each equal part is counted as a section, the rabbit has jumped 3 sections after a break, and has jumped 12 sections after a break 4 times, exactly a week and a half, and the 4th break is exactly at point A, so it passes through a special passage to point B, at this time the circumference of the lake changes and becomes 2 kilometers early; We then divided the new lake into 16 sections, and now the little rabbit rested to 8 times, and jumped a total of 24 segments before resting at point A to rest the Macro ,......And so on, resting until 16, 32, 64, 128, and then the bunny rested at point A. See the table below:

Because: 4 + 8 + 16 + 32 + 64 + 128 + 256 = 5081000 so the rabbit rests 1000 times, and 7 breaks happen to be at point A, and the circumference of the lake is 128 kilometers at this time. So after 1,000 rests, the circumference of the lake is 128 kilometers.

Hello, what are the questions?

Questions. Example 1.

Thank you. Funny] [Eat whales].

Wait a minute. Questions.

Good. Hello, answer 6

The main thing is that these six do not contain isolated elements.

Questions. Good.

There's that option, right?

Questions. Some.

Okay, hope it helps.

Don't forget to like it.

Find the entry point.

Of the 30 people in total, 8 people don't like it, so the remaining 22 people like basketball and table tennis.

There are 15 people who like basketball, then out of 22 people, 7 people only like table tennis. But there are 10 people who like table tennis, and this information shows that there are 3 people who like both sports.

So with 15-3, the number of people who only like basketball is 12.

Let the number of people who like both sports be x, (15+10+8+x)-2x=30, and the solution is x=3;Then the number of people who only love basketball and not table tennis is 15-3=12 people.

12 (3 for both basketball and table tennis, 7 for only table tennis).

As can be seen from the title, there are 30-8=22 children's shoes who like basketball or table tennis. Assuming that each person only likes one sport, there are 15 + 10 = 25 children's shoes who like basketball or table tennis. 22 25, Shenma situation???

Oh, there are 20-22=3 children's shoes who love both basketball and table tennis! So people who like basketball but don't like table tennis have 15-3 = 12 le...

A judges that dust accounts for the sum of the four: 1 3 (1 + 1 3) = 1 4 B accounts for the sum of the four: 1 4 (1 + 1 4) = 1 5 and then accounts for the sum of the four:

1 5 (1+1 5)=1 6 Then Ding accounts for the sum of the four: 1-1 4-1 5-1 6=23 60, so the sum is: 96 Destroy (23 60) = yuan.

A is: Yuan. B is: Yuan.

C is: Yuan. Ding is: 96 yuan.

This number is not easy to calculate! I guess you made a mistake.

Let A, B, C, and D be ABC respectively

d by the Huai group of good lead lead can be set or matched with three equations.

3a=b+c+d

Formula. 4b=a+c+d

Two-form. 5c=a+b+d

Three-style. All right.

Lianli one-two.

Use one formula minus two.

can be obtained. 4a=5b

In the same way, 5b = 6c

Such. Put these together.

You can get the answer.

I won't forget it.

I'll give you an idea.

A = 1 3 (B pants Shenling + C + D).

The amount of money in Jiahu Qi accounts for 1 4 of the total filial piety money of the four people

B = 1 4 (A + C + D).

B's money is 1 5 of the total amount of money of the four people

C = 1 5 (A + B + D).

C's money is 1 6 of the total amount of money of the four men

Find the total number of money: 96 (1-1 4-1 5-1 6)Is the definite number fought for? Do it this way.