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First step is to draw a square whose side is 1cm. Second step is to draw a square whose side is 3cm. Third step is to draw a square whose side is 5cm. At which of the following step will be taken to draw a square whose side is 43cm?
In a certain sequence, the first term is 2, and each term is -2 times the preceding term. What is the sum of the first five terms?
In a list of geometric sequence with a common ratio of 2, the first term is 2, what is the 4th term, 6th term and 8th term, respectively?all the three term.
In a sequence, $$S_{1} = 5$$, $$S_{n} = 2* S_{n-1}$$, for any positive integer n greater than 1.

Quantity A

$$S_{8}$$

Quantity B

$$\frac{S_{21}}{S_{13}}$$


In a sequence, $$S_{1} = 1$$, $$S_{n} = 1/7 * S_{n-1}$$, (n≥2).
Quantity A: $$S_{12}$$
Quantity B: $$S_{26}* 49^7$$
In a certain sequence an,the first term a1= 6, and each term is 3 times higher than the preceding term.

Quantity A

$$2*3^{28}$$

Quantity B

$$\frac{a_{18}}{3^(-10)}$$


In a sequence,if $$a_{n}=3a_{n-1}$$,where n is any integer greater than 1

Quantity A

$$a_{28}$$

Quantity B

$$a_{11}$$


In a sequence, $$a_{1}=1$$, $$a_{2}=2$$, for any n greater than 2, $$a_{n} =(a_(n-1)/a_(n-2) )^2$$, what is the value of $$a_{5}$$?
In a list, the n-th term$$ a_{n}=2+a_{n-1}$$ when n is even, while $$a_{n}=-8+a_{n-1}$$ when n is odd. If $$a_{1}=6$$, then what is the value of $$a_{7}$$?
If $$a_{1}=1$$, $$a_{n}=a_{n-1}+n$$, what is the value of $$a_{49}$$?
If $$a_{1}=1$$,$$a_{n}=2a_{n-1}+r$$,where r is a positive number. if $$a_{1}+a_{2}+a_{3}=35$$,what is the value of r?
List A: 1,-2,3,-4,5,-6-
In the list above, the absolute value of every number is 1 greater than the absolute value of the former number, in positive and negative in turn. What is the sum of the first 99 numbers?
S is a list with 50 numbers. If $$a_{n}= \frac{n+1}{n}-1$$ , where n is an odd number,and $$a_{n} = - a_{n-1}$$, where n is an even number, what is the range of the 50 numbers?
For any positive integer n, $$a_{n}= \frac{1}{n+1}- \frac{1}{n+3}$$

Quantity A

The sum of the first 10 terms

Quantity B

$$\frac{3}{4}$$


$$a_{1}=2$$,$$a_{2}=3$$,当n≥3时,$$a_{n} = a_{n-1} * a_{n-2}$$.What is the value of $$a_{8}$$?
The terms $$a_1, a_2, a_3,........a_n,.......$$ is defined by $$a_{1}=1$$, $$a_{n}=a_{n-1}+n$$ for all integers $$n \geq 2$$. What is the value of $$a_{49}$$?
How many different three-digit positive integers are there that are greater than 300 and contain three of the four digits 1, 2, 3, and 4?
S={1,2,3}
T={1,2,3,4}
Quantity A: The number of different four-digit integers formed by elements from Set S(all elements can be used by more than once)
Quantity B: The number of different three-digit integers formed by elements from Set T(all elements can be used by more than once)
Each digit of a four-digit integer is odd, how many such four-digit integers are there?
Rhonda has 4 different jackets, 3 different skirts, 2 different blouses,and 4 different scarfs that can be worn as part of an outfit. If an outfit consists of a jacket, a skirt, and a blouse with or without a scarf, how many different outfits can Rhonda wear?

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