If AB = BC, then point B is the midpoint of AB, which is a false proposition

Point B is the midpoint of ab
If the vertex of a line segment is its own midpoint, it is impossible unless the line segment degenerates to a point

Give a counter example to show that "if AC = BC, then point C is the midpoint of AB" is a false proposition

In the isosceles triangle ABC, AC = BC, and point C is not the midpoint of ab

It is known that the perimeter of the sector is 40cm. When its radius and central angle are taken, the area of the sector can be maximized? What is the maximum area?

Let the radius and arc length of the sector be r and l, respectively. From the meaning of the title, we can get 2R + L = 40, s = 12lr = 14 · L · 2R ≤ 14 (L + 2r2) 2 = 100. If and only if l = 2R = 20, i.e. L = 20, r = 10, we take the equal sign, then the center angle of the circle is α = LR = 2, when the radius is 10, the center angle of the circle is 2, the area product of the sector is the largest, and the maximum value is 100

How to determine the number of items in the equal ratio sequence?

an=a1*q^(n-1)
q^(n-1)=an/a1
So n = 1 + logq (an / A1)

5x + 1 / 5 x = 52 to solve the equation. Please write the process clearly. Note: it's the seventh grade math problem club in Volume 1. Help me, thank you

5X+X/5=52
25X+X=260
26X=260
X=10

Mom and Dad, your hard-working composition of 450 words

Dad, mom, I'd like to say thank you first! In order to thank you for your upbringing, I'd like to say that you've worked hard, in order to thank you for working hard for me
However, I still have some words from my heart, I want to take this opportunity to express
Mom and Dad, at ordinary times, you always pay great attention to my academic performance, I agree with this point of view, but you can not ignore my ability to live! Although I have some advantages in learning, but in life, my ability to take care of myself is far from other students. Take the matter of making dumplings on the fifth day of the new year for example, I want to learn how to make dumplings with you, But you asked me to watch TV. It's something my classmates can do now, but I'm a teenager
Mom and Dad, I don't want to lose the chance of exercise. I want to tell you that I'm not the child who likes to be coquettish. My daughter needs self-care ability when she grows up
Mom and Dad, have you ever read the book "Harvard girl Liu Yiting"? The reason why she is successful is that her parents not only taught her knowledge, but also taught her self-care ability and safety knowledge. Since every parent wants their children to become a great man, don't be stingy to teach them the ability to live. Let's do more housework
Mom and Dad, my daughter doesn't blame you for not teaching me how to work, but hopes that you can change the educational criteria in your heart and pay attention to my ability as much as you pay attention to learning, OK?
Mom and Dad, I really want to be a student "master" who studies well and works well. I also want to be a person who can live and work freely
I ask Mom and dad not to take all of their daughter's business in the past. I can decide my own business
Ask my parents to give me a free space!
Mom and Dad, I want to tell you
Dad, mom, I'd like to say thank you first! In order to thank you for your upbringing, I'd like to say that you've worked hard, in order to thank you for working hard for me
Mom and Dad, you see me as a pearl, holding me in your hand, not too hard to grasp, afraid of crushing; not too loose, afraid of falling to the ground. In this way, I grow up healthy and happy under your care
Dad, because every time when I am frustrated, you encourage me to tell me that "failure is the mother of success". Don't be discouraged, keep on working hard, and one day I will succeed. This sentence encourages me, and this courage comes to me
Mom, also, because you give me meticulous love - comfort me when I'm sad; chat with me when I'm bored
Dad, I want to tell you that I understand! I understand that you usually educate me and criticize me so that I can become a talent. It's just like the gardener has to constantly water the flowers so that the seeds can grow up and become beautiful flowers
Mom, I also want to say to you, I understand! I know you teach me the truth of life, not for anything else, just want me to be a good person, just like red candle just want to illuminate other people's starting point, so simple
Dad, I want to say sorry to you! Because I'm usually stubborn, disobedient and playful, which makes you worry a lot. But on the head, I'll change it
Mom, I really want to say I'm sorry to you! Because I sometimes misunderstand you, you pay the sweat, but now I'm not that ignorant little child, from now on, I will compare heart to heart, to understand you
Dad, I want to say rest assured to you! Because I will live up to your invisible "investment" in me, so I will strive to get more first and keep rushing forward forever
Mom, I just want to say rest assured to you! Because I will face all the difficulties bravely, as well as setbacks. I will continue to step forward until the invisible end
Mom and Dad, although I will not always get the first, but I know I am your only. Although you are ordinary, but your love is unique, others can not give me. Although I sometimes do not understand you, but I will try to control
Mom and Dad, it's your love that makes my life more colorful. It's your love that makes me experience selfless maternal and paternal love. It's your encouragement that makes me more confident. It's your bright smile that makes my life full of sunshine forever
Mom and Dad, it's your love that lights up the lamp of my life, it's your love that calms the dust of my heart, it's your love that makes me find the beauty of the world, it's your education that makes me understand the importance of patience
Mom and Dad, you once hoped to create a forever sunny sky for me, once hoped that I could stay away from ugliness forever, but as I grow up day by day, let you gradually understand that I belong to myself, have their own thoughts, their own freedom, I have to face the reality of life alone, although we have to face death, my love for you will never change!
Mom and Dad, you always hold that sometimes wealth is not the most important, sometimes knowledge is not the most important, and sometimes talent is not the most important. If I have no ideal, my life will be dark. But mom and Dad, if I don't have your love, my life will be lonely. If I don't have happiness from my heart, everything will be in vain, Sometimes even ignore the love for us
Mom and Dad, you are not conceited when you succeed, you can do it, he is also OK, when you fail, don't be discouraged, everyone is unique, has been buried in my heart, your love will always go with me

(- 3AB) × (- 4AB's Square)

Negative is positive, so the result is not negative
The original formula is 3 × 4 × a × a × B × B & sup2;
=12a²b³

5 (x + y) = 330 (X-Y) * 33 = 330 to solve the equation

5（x+y)=330
So, x + y = 66
However, X-Y = 330 / 33 = 10
Add the above two expressions to get
2x=76
So, x = 38, then y = 66-x = 28

What is the relationship between cuboid volume formula and cuboid volume formula

When the cuboid's length, width and height are equal, the cuboid's volume formula is transformed into the cuboid's volume formula

Given that a belongs to (0, PAI-2), and the square of sina-sinacosa-2cosa = 0, find the value of sin (a + pai-4), sin2a + cos2a + 1

Sin & # 178; a-sinacosa-2cos & # 178; a = 0 ℅ (Sina + COSA) (sina-2cosa) = 0 ℅ Sina + cosa = 0 or sina-2cosa = 0  a belongs to (0, sect  2),  Sina > 0, cosa > 0, Sina + cosa = 0, omit  Sina = 2cosa into sin & # 178; a + cos & # 178; a = 1 to get: cos & # 178; a = 1 / 5, cosa = 1 /

If AB = BC, then point B is the midpoint of AB, which is a false proposition