Accedmychevron_right11thchevron_rightmathchevron_rightSequences And Serieschevron_rightExercise 6.8

Questions

  1. Question 1

    Find the 8th term of the arithmetico-geometric sequence, where the arithmetic part is 1,4,7,1, 4, 7, \ldots and the geometric part is 5,10,20,5, 10, 20, \ldots.

  2. Question 2

    Find the nthn^{th} term of the arithmetico-geometric sequence, where the arithmetic part is 3,7,11,3, 7, 11, \ldots and the geometric part is 2,6,18,2, 6, 18, \ldots.

  3. Question 3

    Consider the arithmetico-geometric sequence defined by arithmetic part: an+1=2n+5a_{n+1} = 2n + 5 and geometric part: bn2=19(3)nb_{n-2} = \dfrac{1}{9}(-3)^n. Find the nthn^{th} term and the sum of first three terms of the arithmetico-geometric sequence.

  4. Question 6

    Show that 21241481816116=42^{\frac{1}{2}} \cdot 4^{\frac{1}{4}} \cdot 8^{\frac{1}{8}} \cdot 16^{\frac{1}{16}} \cdots \infty = 4.

  5. Question 7

    Show that 416464825616=16\sqrt{4} \cdot \sqrt[4]{16} \cdot \sqrt[8]{64} \cdot \sqrt[16]{256} \cdots \infty = 16.

  6. Question 8

    Sum to nn terms the series 2+4x+6x2+8x3+2 + 4x + 6x^2 + 8x^3 + \cdots where x1x \neq 1.

  7. Question 9

    Find the sum to nn terms of the series: 2n+12n1+3(2n+12n1)2+5(2n+12n1)3+\dfrac{2n+1}{2n-1} + 3\left(\dfrac{2n+1}{2n-1}\right)^2 + 5\left(\dfrac{2n+1}{2n-1}\right)^3 + \cdots.

  8. Question 10

    Prove that 1+2(1+1n)+3(1+1n)2+1 + 2\left(1+\dfrac{1}{n}\right) + 3\left(1+\dfrac{1}{n}\right)^2 + \cdots to nn terms =n2= n^2.

  9. Question 11

    Sum the series to nn terms 2+5x+8x2+11x3+2 + 5x + 8x^2 + 11x^3 + \cdots and deduce the sum to infinity if x<1|x| < 1.