A general formula of sequence 5 / 3,2 / 1,11 / 5,7 / 3,... Is?

A general formula of sequence 5 / 3,2 / 1,11 / 5,7 / 3,... Is?

It can be seen as 5 / 3, 8 / 4, 11 / 5, 14 / 6
Then we can use incomplete induction to see an = (3N + 2) / (n + 2)

There are 43 pieces of RMB 5 yuan and 10 yuan in total, 340 yuan in total. How many pieces of RMB 5 yuan and 10 yuan in total

Let 5 yuan x sheets and 10 yuan y sheets, then x + y = 43,
5x+10y=340

Find the rule: 1,4,9, a, 25,36,49,. Then a = (). A.16 b.13 c.14 d.20

1,4,9, a, 25,36,49,. Then a = (16)

Proof: there are infinitely many prime numbers

Suppose there are finite numbers, A1, A2,..., at, then A1 * A2 * A3 *. At + 1 cannot be divisible by A1, A2,..., at, A1 * A2 * A3 *. * at + 1 is a prime number

What is the maximum value of y = (sin squared x-1) (COS squared x + 3)

The maximum value is 0
First of all, let's look at the first item
(the square of sin x-1) is less than or equal to 0
Second
(COS square x + 3) is greater than 0
The multiplication of two terms is less than or equal to 0 (if and only if the square X of sin = 1, the equal sign holds)

As shown in the figure, in the rectangular coordinate system, the coordinates of point a are (- 3, - 2), ⊙ the radius of a is 1, P is a moving point on the x-axis, PQ cuts ⊙ a to point Q, then when PQ is the minimum, the coordinates of point P are ()
A. (- 4,0) B. (- 2,0) C. (- 4,0) or (- 2,0) d. (- 3,0)

Connect AQ and AP. According to the property theorem of tangent, AQ ⊥ PQ is obtained. To minimize PQ, only AP is needed. According to the shortest vertical line segment, make AP ⊥ X axis at P, which is the point P. at this time, the coordinate of P is (- 3, 0). So D is selected

If the natural numbers are arranged according to the law, the number in the sixth row and the forty fifth column is
First column, second column, third column, fourth column
First line 1 2 9 10
The second line 4 3 8 11
The third line 5 6 7 12
The fourth line 16 15 14 13
The fifth line is 17
I want a process, thank you

The first row of odd sequence is the square of the value of the column, and the odd sequence is decreasing from bottom to top. The first row of the 45th column is the square of 45, that is, 2025, and each next row is decreasing by one
The sixth line is 2020

Any natural number has a reciprocal ()

Wrong, if 0 / 0, it's meaningless

First row 1, second row 2.3, third row 4.5.6, fourth row 7.8.9.10, fifth row 11.12.13.14.15. What is the fifth number in the sixth row?

20

Repeat the natural number 1, 2, 3, 4, 5, 6, 7, 8, 9 to form a 1993 digit. Can this number be divided by 3?

No, because the basis of judging whether a number can be divided by 3 is whether the sum of the numbers added to each digit of the number can be divided by 3. Since the number is 1993 digits, it is made up of 9 numbers repeatedly. Divide 1993 by 9 = 221 plus 4, so the sum of the numbers on each digit of the number is (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9) 22