There are 8 different books, including 3 mathematics books, 2 foreign books and 3 other books. If you put these books in a row on the shelf, you can count them There are 8 different books, including 3 mathematics books, 2 foreign books and 3 other books. If you put these books on the shelf in a row Mathematics books and foreign books are arranged together. The answer is 1440

Put them together
3!*2!*5!=
The total number of mathematics books * the total number of foreign books * the total number of categories (mathematics books are regarded as one category, foreign books as one category, and other books as one category, totally 3 categories)

There are 8 different books, including 3 mathematics books, 2 foreign language books and 3 Chinese books. If these books are arranged in a row on the bookshelf, if these books are arranged in a row on the bookshelf, the books of each subject are arranged together____ Species

That is, step-by-step arrangement, first mathematics, foreign language and Chinese all kinds of row (3 * 2 * 1) (2 * 1) (3 * 2 * 1) in each subject row (3 * 2 * 1) all multiply together OK

There are 8 different books, including 3 mathematics books, 2 foreign books and 3 other books. If these books are arranged on the shelf, the probability that the mathematics books are arranged together and the foreign books are also arranged together is ()
A. 128B. 124C. 18D. 136

According to the meaning of the title, eight different books are arranged together, there are A88 methods, mathematics books are arranged together, and foreign books are also arranged together, there are A33 × A22 × A55 methods, so the probability that mathematics books are arranged together and foreign books are also arranged together is A33 × A22 × A55 & nbsp; A88 = & nbsp; 128 × 7 × 6 = 128, so choose a

Given the odd function f (x) defined on R, when x > 0, y = x & # 178; + X-1, then when x < 0, f (x) =?

x0
So f (- x) = (- x) &# 178; + (- x) - 1 = x & # 178; - X-1
For odd functions, then f (x) = - f (- x)
therefore
x

How many chickens and rabbits does grandma raise? There are 13 more chickens than rabbits and 16 more chicken legs than rabbits. How many chickens and rabbits do you raise?

Suppose there are x chickens, then there are (X-13) rabbits
Taking the number of legs as the equivalent equation
All chickens have 2x legs
All rabbits have 4 legs (X-13) * (rabbits have 4 legs and chickens have 2 legs)
Then (X-13) * 4 + 16 = 2x
*It's riding

What are tan2 θ and tan2 / θ respectively?

Finding the maximum value by matching method: 2x square + 5x-3

Square of 2x + 5x-3
=2（x²+5/2x）-3
=2(x+5/4)²-25/8-3
=2(x+5/4)²-49/8
When x = - 5 / 4, take the minimum value = - 49 / 8

Translate point a (- 2, - 3) to the left for 3 unit lengths to get point B, then the coordinate of point B is ()
A. （1，-3）B. （-2，0）C. （-5，-3）D. （-2，-6）

∵ point a (- 2, - 3) is shifted to the left by 3 unit lengths to get point B. the abscissa of point B is - 2-3 = - 5, and the ordinate is unchanged, that is, the coordinate of point B is (- 5, - 3), so select C

If the function is an odd function with period 5, f (- 3) = 1, Tana = 2, f (20sina * Sina)=

Sina / cosa = Tana = 3sina = 2cosasin & # 178; a = 4cos & # 178; a because Sin & # 178; a + cos & # 178; a = 1, so 5cos & # 178; a = 1cos & # 178; a = 1 / 520 sinacosa = 20 (2cosa) cosa = 40cos & # 178; a = 8t = 5, odd function, so the original formula = f (8) = f (3 + 5) = f (3) = - f (- 3) = - 1

The zeros of function f (x) = x2-4 / X are in the interval

(1,2)