Xiao Fang finished reading a story book in three weeks. In the first and second weeks, she read four chapters of the book Xiao Fang finished reading a story book in three weeks. In the first and second weeks, she read 3 / 4 of the whole book, in the second and third weeks, she read 5 / 7 of the whole book, and in the second week, what percentage of the whole book? I want to know

Xiao Fang finished reading a story book in three weeks. In the first and second weeks, she read four chapters of the book Xiao Fang finished reading a story book in three weeks. In the first and second weeks, she read 3 / 4 of the whole book, in the second and third weeks, she read 5 / 7 of the whole book, and in the second week, what percentage of the whole book? I want to know

3 / 4 + 5 / 7 = 41 / 28
41-1 out of 28 = 13 out of 28
A: 13 / 28 of the book
Why don't you give me money? I'm stingy

I also want to ask a question, a story book has 87 pages, Xiaofang read 39 pages
Xiaogang said: "the remaining pages are 10 pages less than two-thirds of the book. Is he right?

Remaining = 87-39 = 48 pages
87 × 2 / 3-10 = 48 pages
He's right

Given that the height h of the cone is 3 and the radius r of the bottom surface is 1, then the side area of the cone is 0______ ．

According to Pythagorean theorem, AC = AO2 + CO2 = (3) 2 + 12 = 2; the length of DC is ⊙ o circumference, then the length of DC is 2 π 1 = 2 π, then the side area of cone is 12 × 2 π × 2 = 2 π. So the answer is 2 π

Does the sum of equal ratio sequence satisfy Sn = a ^ n + B?
The sum of arithmetic sequence satisfies Sn = an ^ 2 + BN?

Sum of equal ratio sequence Sn = AA ^ n + B

If there is a definition: int m = 4, n = 5; float K;, then the following expression in accordance with C language syntax is (b)
A.(m+n)*=k B.m=(n==5) C.k=float(n)/m D.n%2.5
For AC's explanation

A. (M + n) * = k the left side is the object to be assigned. It can only be a variable, not an expression
C. The cast of k = float (n) / M is wrong. It should be k = (float) n / m

My teacher should write 400 words with deeds

Miss Liu is our math teacher. She is over thirty years old. She is tall and slender. She is simple and easy to wear. I think any clothes look good on her. Miss Liu has a pair of special eyes. Her eyes can speak. Her encouraging eyes often help us overcome our fear of difficulties and enhance our confidence in solving problems, Every little action that has nothing to do with learning in class can't escape his keen eyes. She gives us severe eyes, which makes us dare not act rashly any more. It is under her encouragement and encouragement that we grow up day by day. Miss Liu has a caring heart. Once, I accidentally broke my head in school, and Miss Liu saw it, I ran downstairs to help me up and sent to the medical room for the medical teacher to give me medicine. Seeing her anxious look and loving eyes, I felt as if my parents were beside me, which made me feel warm. I felt that my wound didn't hurt at all
I love our teacher!
When I finished the fifth grade and went to the sixth grade, our head teacher Niu was transferred to junior high school. My classmates and I are looking forward to the arrival of the new teacher
As soon as I pushed the door, a 40-50-year-old female teacher came in - our new head teacher, Mr. Lu. Mr. Lu was not tall, with a Chinese face and short hair. I didn't like Mr. Lu at first, but two things changed my view of Mr. Lu
Once, I had nothing to do with my classmates, so I went to the Internet bar to play. I didn't play at first, but I went to pay money and played. An hour passed quickly, but we never thought that it had already spread to teacher Lu. The next morning, as soon as teacher Lu came into the classroom, he asked me, "where did you go yesterday, dun Yufei?", I felt uncomfortable all over, thinking: did the teacher know about going to the Internet bar? After that, I couldn't keep my bottom again. Who knows, after we confessed, Mr. Lu didn't inform our parents, but kept the secret for us. I almost cried, and forced to hold back tears in my eyes
Another time I gave an endorsement to Mr. Lu. I accidentally saw Mr. Lu's right hand. That right hand has been corroded by white chalk ash, and it is no longer as ruddy as normal people. In my heart, a wave of respect arises spontaneously. What is the reason? There is only one answer, that is what you pay for us, for our 24 flowers of our motherland
Mr. Lu, although you have only taught us for one year, I will always cherish what you have paid for us. Mr. Lu, I am going to graduate soon. I wish you youth and prosperity

The real number a B satisfies a ^ 3 + B ^ 3 + 3AB = 1 to find the value of a + B
RT

∵ A & sup3; + B & sup3; = (a + b) & sup3; - 3AB & sup2; - 3A & sup2; b = (a + b) & sup3; - 3AB (a + b); ∵ original formula = (a + b) & sup3; - 3AB (a + B) + 3AB = (a + b) & sup3; - 3AB (a + B-1) = 1; ∵ (a + b) & sup3; - 3AB (a + B-1) - 1 = 0, that is [(a + b) & sup3; - 1] - 3AB (a + B-1) = 0; ∵ (a + B-1)

How to solve the equation X-1 / x = 120 / 11
Using factorization

x-1/x=120/11
11x^2-120x-11=0
(11x+1)(x-11)=0
x=-1/11
x=11

A formula for calculating the surface area and volume of a rectangular triangle square

If cos (a + π / 6) = 2 / 3 and a is an acute angle, cosa can be obtained
I'm converting a + π / 6 to Pai minus (5 / 6 pai-a)
Can also do, but finally with two answers, do not need a computer will be more than one
Sheinengz told me what to do

Because a is an acute angle, sin (a + Pai / 6) = 5 ^ 0.5/3, so cosa = cos (a + Pai / 6-pai / 6) = cos (a + Pai / 6) cospai / H + sin (a + Pai / 6) sinpai / 6 = 2 / 3 * 3 ^ 0.5 / 2 5 ^ 0.5 / 3 * 1 / 2 = (2 * 3 ^ 0.5 ^ 0.5) / 6