Let the common ratio Q of the equal ratio sequence an

Let the common ratio Q of the equal ratio sequence an

S4=a1(1-q^4)/(1-q)=5a1(1-q^2)/(1-q)
1+q^2=5
q^2=4
Because Q
Let the common ratio Q, then A1 = A3 / Q2, A2 = A3 / Q, A4 = A3 · Q. From A3 = 2, S4 = 5s2, then calculate q = ± 2, Q < 1, so q = - 2, A1 =, an = · (- 2) n-1 is obtained
The product of all the factors of a number is 30, which is a two digit number, a multiple of 5 and can be divided by 12. What is the number?
Two digits, a multiple of 5, can be divided by 12
5 and 12 are coprime
The two digit number can only be 5 * 12 = 60
So, 60
Sixty
There are 55 people in Bruce Lee's class. If each person has a bottle, how much will it cost at least?
15 / 3 * 12 = 60, 60 can buy 15 + 1 = 16 bottles, 55 / 16 = 3 more than 7. The total cost is 3 * 60 + 7 * 12 / 3 = 208
It is known that {an} is an arithmetic sequence, the sum of the first n terms is Sn, A3 = 11, S9 = 153, (1) find the general term formula of the sequence {an}; (2) let an = log2bn, prove that {BN} is an arithmetic sequence, and find the sum of the first n terms and TN
(1) Then A3 = a1 + 2D = 11s9 = 9a1 + 9a1 + 9 × 82d = 153, and the solution is A1 = 5D = 3, the general term formula of A1 = 5D = 3 {{an} {an = 5 + 3 (n-1) = 3N + 2; (2) an = log2bn = 3N + 2, and then A3 = a1 + 2D = 11s9 = 9a1 + 2D = 11s9 = 9a1 + 9 × 82d = 153, and the solution is the formula of A1 = 5 = 5D = 3, the general term formula of A1 = 5D = 3 {5D = 3} {3}} {3} n = 32.bn + 1bn + 1bn = 23 (n + N + 23 (n + N + 1) + (n + 1) + (n + 23 (n + 1) + 223n + 23 (n + 23 (n + 1) + (n + 1) + 223n + 23 (n + 1) + 223n + 2231 − 8 = 327 （8n-1）．
Between 5 and 25___ Can be___ Division___ Yes___ Multiple of___ Yes___ What's the factor?
It's a pity that I forgot all about it=||
please help me
Between 5 and 25__ 25_ Can be__ 5_ Division___ 25 yes__ 5_ Multiple of__ 5_ Yes_ 25__ Factor of
A and B two convenience stores go to the wholesale station to purchase a batch of drinks, a total of 25 cases. Due to the different geographical location of the two stores, the sales price of a store is 10 yuan more than that of B store. When the two stores sell out all the drinks, the turnover of a store is 1000 yuan, 350 yuan less than that of B store. How many cases of drinks should a and B store purchase?
Let store a purchase x boxes and store b purchase (25-x) boxes. (1 point) from the meaning of the question, we can get 1000x − 135025 − x = 10 (4 points) x2-260x + 2500 = 0, (2 points) X1 = 10; x2 = 250. (2 points) x = 10 is the solution of the original fraction equation and meets the meaning of the question, 25-x = 25-10 = 15 (boxes). Answer: store a purchase 10 boxes and store b purchase 15 boxes. (1 point)
It is known that in the increasing arithmetic sequence {an}, A1 = 2, A1, A3, a7 are proportional sequence, the sum of the first n terms of {BN} is Sn, and Sn = 2n + 1 − 2. (1) find the general formula of {an}, {BN}; (2) let CN = ABN, find the first N and TN of {CN}
Let (2 + 2D) 2 = 2 (2 + 6D), D ﹥ 0 ﹥ d = 1, an = n + 1 ﹥ Sn = 2n + 1 − 2. ﹥ B1 = S1 = 2bn = sn-sn-1 = 2n + 1-2n + 2 = 2n (n ≥ 2). When n = 1, BN = 2n (2) ﹥ CN = ABN = 2n + 1 ﹥ TN =
A three digit number is not only a multiple of 2, but also a factor of 3 and 5. The minimum and maximum of the three digit number are
2*3*5=30
So three digits is a multiple of 30
Minimum = 120
Max = 990
120， 990
120,990
one hundred and twenty point nine nine zero
Xiao Ming went to the store to buy drinks. The money he brought was more than 1 yuan for three bottles, but less than 5 yuan for five bottles. How much is each bottle?
Fourth grade primary problems, not equations, ordinary algorithm
(5 + 1) / (5-3) = 3 (yuan)
3 * 3 + 1 = 10 yuan
Answer: each bottle of drink is 3 yuan, Xiao Ming has 10 yuan with him!
It is known that in the equal ratio sequence {an}, A1 = 1, A4 = 81. If the sequence {BN} satisfies BN = lgan / Lg3, then the first n terms of the sequence {1 / bnbn + 1} and Sn =?
There are people in the house