Question 4:
The sum of the first n terms of the geometric progression 5, 15, 75, … is 5465.
Find the value of n.
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-4-1024x815.png)
The sum of the first n terms of the geometric progression 5, 15, 75, … is 5465.
Find the value of n.
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-4-1024x815.png)
Question 5:
The first three terms of a geometric progression are 5k + 6, 2k, k – 2.
Find
(a) the positive value of k,
(b) the sum from the third term to the sixth term, using the value of k obtained in (a)
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-5-1-1024x616.png)
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-5-2-1024x690.png)
The first three terms of a geometric progression are 5k + 6, 2k, k – 2.
Find
(a) the positive value of k,
(b) the sum from the third term to the sixth term, using the value of k obtained in (a)
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-5-1-1024x616.png)
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-5-2-1024x690.png)
Question 6:
The first three terms of a sequence are 2, x, 18. Find the positive value of x so that the sequence is
(a) an arithmetic progression,
(b) a geometric progression.
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-6-1024x550.png)
The first three terms of a sequence are 2, x, 18. Find the positive value of x so that the sequence is
(a) an arithmetic progression,
(b) a geometric progression.
Solution:
![](http://spmaddmaths.blog.onlinetuition.com.my/wp-content/uploads/sites/3/2018/01/Picture6-SPM-GP-6-1024x550.png)