To find the first three terms, plug 1, 2, and 3 in for n:Term 1: 2(1) - 1 = 1Term 2: 2(2) - 1 = 3Term 3: 2(3) - 1 = 5
29
You use the FOIL method. First terms Outer terms Inner terms Last terms.
We need the common difference to accurately get the first term and then use it to find the sum of the first 20 terms.
What is the sum of the first 27 terms of the geometric sequence -3, 3, - 3, 3, . . . ?
Which sequence? Oh, that one! The first three terms are 1, 2 and 72.
3 7 11
To find the first 5 terms, plug 1, 2, 3, 4 and 5 in for n:3*1-3 = 03*2-3 = 33*3-3 = 63*4-3 = 93*5-3 = 12The first five terms are 0, 3, 6, 9 and 12.
it is 8.
4, 8, 12
3
n = 1 ---> 3 * 1 + 3 = 6 n = 2 ---> 3 * 2 + 3 = 9 first 2 have difference of 3, so you can keep adding 3 to find more terms. 6, 9, 12, 15
To find the first three terms, plug 1, 2, and 3 in for n:Term 1: 2(1) - 1 = 1Term 2: 2(2) - 1 = 3Term 3: 2(3) - 1 = 5
The first four terms are 3 9 27 81 and 729 is the 6th term.
Suppose the first term is a, the second is a+r and the nth is a+(n-1)r. Then the sum of the first five = 5a + 10r = 85 and the sum of the first six = 6a + 15r = 123 Solving these simultaneous equations, a = 3 and r = 7 So the first four terms are: 3, 10, 17 and 24
5
3, 15, 75, 375