The first fourth term of the equation are "3, 8, 13 and 18".
Explanation:
We have,
f(n) = f(n - 1) + 5
and f (1) = - 2 ........ (1)
To find, the first four terms of the given equation = ?
Put n = 2, 3, 4, 5, .....
Put n = 2, we get
f(2) = f(2 - 1) + 5 = f(1) + 5
Using (1), we get
f(2) = - 2 + 5 = 3 ........ (2)
Put n = 3, we get
f(3) = f(3 - 1) + 5 = f(2) + 5
Using (2), we get
f(3) = 3 + 5 = 8 ........ (3)
Put n = 4, we get
f(4) = f(4 - 1) + 5 = f(3) + 5
Using (3), we get
f(4) = 8 + 5 = 13 ........ (4)
Put n = 5, we get
f(5) = f(5 - 1) + 5 = f(4) + 5
Using (4), we get
f(5) = 13 + 5 = 18
Thus, the first fourth term of the equation are 3, 8, 13 and 18.