![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
In {an}, A3 = 1 / 2, A9 = 8, then the value of A5 * A6 * A7 is A9/A3=(A1×q^8)/(A1×q^2)=q^6=8/(1/2)=16 q^3=±4 How to get Q ^ 3 = ± 4 in this non analytic expression? That is, Q ^ 6 = 16, how to delimit Q ^ 3 = ± 4?
q^6=(q^3)^2=16
So Q ^ 3 = ± 4
In the equal ratio sequence {an}, A3 = 1 / 2, A9 = 8, find A5 × A6 × A7
a3*a9=a6^2=4
a5*a7=a6^2=4
a5*a6*a7=4a6
a^6=±2
a5*a6*a7=±8
RELATED INFORMATIONS
- 1. In the equal ratio sequence {an}, a1 + A2 + a3 = - 3, A1 * A2 * A3 = 8,1, find an 2, find A1 * A3 * A5 * A7 * A9
- 2. If a1 + A5 = 2, A3 + A7 = 6, then A5 + A9
- 3. A1 = 1, N, an, Sn are equal difference sequence. It is proved that {Sn + N + 2} is equal ratio sequence
- 4. It is known that real number sequence an is equal ratio sequence, where A7 = 1, and A4, A5 + 1, A6 are equal difference sequence. The general term formula of sequence an is obtained fast
- 5. If q = - 1 / 2, then a1 + a3 + A5 / A3 + A5 + A7=
- 6. It is known that SN is the sum of the first n terms of the equal ratio sequence {an}, S2, S6 and S4 are equal difference sequence, and the common ratio Q of the sequence {an} is obtained?
- 7. In {an} where all items are positive proportional sequence, A2 * A4 = 4, a1 + A2 + a3 = 14, then the value of the largest positive integer n with an + an + 1 + an + 2 > 1 / 9 is satisfied?
- 8. Let positive number sequence {an} be equal ratio sequence, and A2 = 4, A4 = 16, find [LGA (n + 1) + LGA (n + 2) + +The value of the limit of LGA (2n)] / N ^ 2
- 9. The arithmetic sequence an is an increasing sequence, the sum of the first n terms is Sn, and A1, A3 and A9 are equal proportion sequence, S5 = the square of A5. The general term formula of the sequence an is obtained
- 10. Proportional sequence, A3 and A9 are the two roots of equation x equal square + 3x + 1, A6=
- 11. Equal ratio sequence a1 + A2 = 3, A3 + A4 = 6, find S8
- 12. In the arithmetic sequence an, the tolerance d = 1 / 2, A4 + A17 = 8, then A2 + A4 + A6 + +a20=?s20=?
- 13. If the tolerance of {an} is d = 1, A4 + A17 = 8, then A2 + A4 + A6 +... + A20 =? The online answer is like this a4+a17=8 So, 2a10 + D = 8 a10＝3．5 a11＝4．5 So, a2+a4+a6+...+a20 = 10 × a11 = 45
- 14. In the root sign 3-A divided by A-1, what is the value range of a?
- 15. Given (x + my) (x + NY) = x ^ 2-5xy + 3x ^ 2, find the algebraic formula 3mn-2 (M + n)
- 16. If 3x ^ A + 1y ^ B and - 1 / 2x ^ 3-ay ^ 2a are similar, then a = (), B = ()
- 17. This is about the addition and subtraction of integers There is such a problem: find the value of the polynomial y to the second power - 2XY + y + 1 / 2, where x = 10000 is mistaken for 1000, and the result is correct. Can you tell the Dao Li in it? You'll get points if you get it right!
- 18. An addition and subtraction problem of mathematical integral There is such a problem, "when a = 2, B = - 2", find the value of polynomial 2 (a ^ - 3AB + 3b) - 3 (- A ^ 2-2ab + 2b). Ma Xiaohu fried a = 2 into a = - 2. Wang Xiaozhen did not copy the wrong problem, but they all made the same result. Do you know what happened? Please explain the reason
- 19. Addition and subtraction of mathematical integral Manager Li has a mobile phone and a PHS. When paying the phone bill in October, manager Li found that the cost of mobile phone is 1.8 times that of PHS. In order to control and reduce the phone bill, manager Li decided to take certain measures. It is estimated that the cost of mobile phone will be reduced by 40% in November and that of PHS will be increased by 30%. Do you think manager Li's measures are feasible? Explain the reasons
- 20. Junior high school mathematics problems (integral addition and subtraction) （m+2n）-（m-2n） （2ab+5a²-2b²）-（a²+2ab-2b²） 2x-3（x-2y+3z)+2（3x-3y+2z） 8m²-[4m²-2m-（2m²-5m）]