In the known sequence {an}, a1 + a3 = 10, A4 + A6 = 54, find the sum of the fourth term and the first five terms
Let the common ratio be q According to the known results, a1 + a1q2 = 10a1q3 + a1q5 = 54 (3 points) ② A1 (1 + Q2) = 10a1q3 (1 + Q2) = 54 (5 points) ② △ ① get & nbsp; Q3 = 18, that is, q = 12 (7 points) substituting q = 12 into (1) to get A1 = 8 (8) A4 = a1q3 = 8 × (12
RELATED INFORMATIONS
- 1. Given the equal ratio sequence a1 + A6 = 11, A3 * A4 = 32 / 9, find an
- 2. Given an equal ratio sequence an, a1 + a3 = 10, A4 + A6 = 5 / 4, find A4 and S5
- 3. Given that {an} is an equal ratio sequence, and a1 + a3 = 10, A4 + A6 = 5 / 4, find A4 and S5
- 4. If the sequence {an} satisfies that A1, a2-a1, a3-a2,... Are equal ratio sequences with 1 as prime minister and 3 as common ratio, then an______
- 5. The known sequence {an} satisfies A1, a2-a1, a3-a2 an-an-1,… Is the prime minister is 1, the common ratio is one third of the equal ratio sequence 1 The known sequence {an} satisfies A1, a2-a1, a3-a2 an-an-1,… The prime minister is 1, the common ratio is one-third of the equal ratio series 1. Find the general term formula of sequence {an} 2. If BN = (2n-1) an, find the first n terms and Sn of sequence {BN}
- 6. The known sequence {an} satisfies A1, A2-A3, a4-a3 , an-a (n-1) is the expression of finding an from the equal ratio sequence (1) with Prime Minister of 1 and common ratio of 1 / 3 (2) If BN = (2n-1) an, find the first n terms and Sn of the sequence {BN} It's wrong. (1) it should be A1, a2-a1, a3-a2 ,
- 7. Let {an} be an equal ratio sequence with the first term of 1 and the common ratio of - 2, then a1 + | A2 | + a3 + | A4|
- 8. Given that the ratio of the distance between the left and right focal points of point m and hyperbola x216 − Y29 = 1 is 2:3, the trajectory equation of point m is______ .
- 9. In the plane rectangular coordinate system xoy, it is known that the abscissa of a point m on the hyperbola x2 / 4-y2 / 12 = 1 is 3, then the distance from m to the right focus of the hyperbola is? If the abscissa of a point m on the hyperbola x2 / 4-y2 / 12 = 1 in the plane rectangular coordinate system xoy is 3, then the distance from m to the right focus of the hyperbola is? Through point a (60), make straight line L and hyperbola x2 / 16-y2 / 4 = 1 intersect at B C. two points a are the midpoint of line BC, then the equation of straight line L is? Through point a (6,1), make straight line L and hyperbola x2 / 16-y2 / 4 = 1 intersect at B C. two points a are the midpoint of line BC, then the equation of straight line L is?
- 10. Given that there is a point P (6, m) on the hyperbola x2 / 9-y2 / 16 = 1, what is the distance from the point P to the right focus? If you can, give me a more complete process
- 11. In the equal ratio sequence, Sn = a1 + A2 + a3 + +An, given A3 = 2s2 + 1, A4 = 2s3 + 1, what is the common ratio?
- 12. In the equal ratio sequence {an}, Sn = a1 + A2 +... + an, A3 = S2 + 1, A4 = S3 + 1, then q is the common ratio=
- 13. In the equal ratio sequence an, Sn = a1 + A2 + a3=______ fast
- 14. In an, an > 0, A1 = 1, a1 + A2 + a3 = 7, find an and Sn
- 15. The sum of the first n terms of an is Sn, A1 = 2, and the mean difference of A2, A3 is S2 The sum of the first n terms of an is Sn, A1 = 2, and the median of the differences of A2 and A3 is S2, 1. The general formula of an 2. Let BN = log2an, find the first n terms and TN of sequence {BN}
- 16. Please summarize your problem here, where a1 + A2 + a3 = 18, A2 + a3 + A4 = - 9, and Sn = a1 + 2A2 + 3 (A3 + A4 +) +Then limsn=
- 17. In the equal ratio sequence an, if a1 + A2 = 3. A3 + A4 = 27. And Q > 0. An and Sn (2) In the arithmetic sequence an, if a3a7 = 12, A2 + A8 = 8, and d > 0, find an and Sn
- 18. The tangent equation of curve y = ex + 1 at point (0,2) is______ .
- 19. The tangent equation and normal equation of the cubic power of y = x at x = - 1, etc
- 20. Find the point on the square of the curve X = t, y = t, and the third power of Z = t, so that the tangent of the point is parallel to the plane x + 2Y + Z = 4