Test: Geometric Series I - Challenging

Double click on maths expressions to zoom
Question 1:   In the geometric series   a n   it’s known that   a 10 =2 . Find product of the nineteen first terms of this progression.
2 19
2 10
38
3.8
Question 2:   The second term of the geometric series is   a 2 =4 . Find the product of three first terms of this progression.
16
64
128
32
Question 3:   Find the initial term and the common ratio of a geometric series   a n , if   a 5 =3 a 3 ;  a 6 − a 2 =48 .
a 1 =2 3   ,  r= 3    or    a 1 =−2 3   ,  r=− 3
a 1 =2 3   ,  r= 3
a 1 =−2 3   ,  r= 3    or    a 1 =2 3   ,  r=− 3  
a 1 =0.2  ,  r= 3
Question 4:   Find the initial term and the common ratio of a geometric sequence which consists of  6  terms. The sum of the first three terms is  168 , the sum of the last three terms is  21  .
a 1 =24; r=2
a 1 ≈147.3; r= 1 8
a 1 =96; r= 1 2  
a 1 ≈165.4; r= 1 4
Question 5:   The sum of three positive sequent numbers that make up an arithmetic series   a n   is  21 . If you add  2, 3, 9  to these numbers, they would make up a geometric series   b n . Find these initial numbers.
5, 10, 20
3, 7, 11
1, 7, 49
2, 7, 12
Please note, you have solved only half of the test. For the complete test get a Must Have account. Get started