There were 1050 science and technology books and literature and art books in the school library. To make the ratio of science and technology books to Literature and art books 4:3, we need to buy another 56 science and technology books, How many original science and technology books?

1050 + 56 = 1106
4 + 3 = 7
1106 divided by 7 = 632
632-56 = 576
Answer: original science and technology book 576

If the ratio of science and technology books to Literature and art books is 3:5, then literature and art books are 25% less than science and technology books______ (judge right or wrong)

(5-3) △ 3, = 2 △ 3, = 23; a: there are 23 more literature books than science and technology books

If the ratio of science and technology books to Literature and art books is 3; 5, then literature and art books are a few percent less than science and technology books

2/5

Given the first n terms and Sn of sequence an = n-5an-85 (1), find the general formula of an (2) let BN = log5 / 6 × 1-a1 / 18 + log5 / 6 × 1-a2 / 18 +... + log5 / 6 × 1-an / 18, find the first n terms and TN of sequence 1 / BN

Sn=n-5an-85 (1)
S（n+1）=n+1-5a（n+1）-85 (2)
(2) (1) it is concluded that 6A (n + 1) = 1 + 5An
That is, a (n + 1) - 1 = (5 / 6) (an-1)
From S1 = A1 = 1-5a1-85, A1 = - 14
So {an-1} is an equal ratio sequence of the first term - 15, common ratio 5 / 6
So an = (- 15) * (5 / 6) ^ (n-1) + 1
(2)bn=log5/6(5/6*(5/6)^0)+log5/6(5/6*(5/6)^1)+log5/6(5/6*(5/6)^2)+...+log5/6(5/6*(5/6)^(n-1))
=1+0+1+1+1+2+1+3+...+1+(n-1)
=n+(0+n-1)*n/2
=n(2+n-1)/2
=n(n+1)/2
1/bn=2/(n(n+1))=2[1/n-1/(n+1)]
Tn=2[1-1/2+1/2-1/3+,.+1/n-1/(n+1)]
=2[1-1/(n+1)]
=2n/(n+1)

If a room is paved with 30cm long square bricks, 100 pieces are needed. If a room is paved with 50cm long square bricks, how many pieces are needed?

Let x block be required, 30 × 30 × 100 = 50 × 50 × x, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 2500x = 900 × 100, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 2500x = 90000, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 36; a: 36 blocks are required

Fifty six nationalities, fifty-six flowers, fifty-six brothers and sisters are one family

The unity of 56 nationalities is written by means of metaphor

Sinacosa is equal to 1 / 8, which is obtained by finding (COSA minus Sina) to the power of 2

Uncle teaches you coordinate method
y/r*x/r=1/8
xy/r^2=1/8
(x/r-y/r)^2=(x-y)^2/r^2=(x^2+y^2-2xy)/r^2=(r^2-r^2/4)/r^2=3/4

The length of three sides of a triangle is 2.5cm, 4cm and 3cm respectively; the length of three sides of another triangle is 3.2cm, 2.4cm and 2cm respectively. Are the two triangles similar? Why?

Yes, because 3.2 / 4 = 2.4 / 3 = 2 / 2.5 = 4 / 5, that is, the three sides are proportional, so the triangles are similar

Simple high school math problem
3. If ≠ KX + 2 holds for all x ≥ 5, then the value range of K is
step
If (X-5) ≠ KX + 2 holds for all x ≥ 5, then the value range of K is
There should be a part of the value range
How to ask for that part

The original formula can be reduced to X-5, which is not equal to (KX + 2) ^ 2
Then X-5 is not equal to
k^2x^2+4+4kx
It can be concluded that (KX) ^ 2 + (4k-1) x + 9 is not equal to 0
When k = 0, it is not rounding
When k is not equal to 0 and K ^ 2 > 0, if the opening of the image is upward and not equal to 0
There must be its minimum value > 0, that is, (4ac-b ^ 2) / 4A > 0
The solution is K1 / 10

Find the increment and differential of y = x ^ 3-x at point x0 = 2 when (1) △ x = 0.1 and (2) △ x = 0.01

Y = x & # 179; - X so y '= 3x & # 178; - 1, where x0 = 2, the derivative value is 11y0 = 2 & # 179; - 2 = 6dy = y ` dx1) Δ y = (2.1 & # 179; - 2.1) - Y0 = 7.161-6 = 1.161dy = 11dx = 1.12) Δ y = (2.01 & # 179; - 2.01) - Y0 = 6.110601-6 = 0.110601dy = 11dx = 0.11

There were 1050 science and technology books and literature and art books in the school library. To make the ratio of science and technology books to Literature and art books 4:3, we need to buy another 56 science and technology books, How many original science and technology books?