JAMB - Mathematics (2023 - No. 38)
What is the general term of the sequence 3, 8, 13, 18, ...?
5n - 2
5n + 2
5
5n
คำอธิบาย
Given the sequence 3, 8, 13, 18, ... which is an arithmetic sequence
a = 3
d = T\(_2\) - T\(_1\) = 8 - 3 = 5
The general term of an A.P is:
T\(_n\) = a + (n - 1)d
⇒ T\(_n\) = 3 + (n - 1)5
= T\(_n\) = 3 + 5n - 5
∴ T\(_n\) = 5n - 2
a = 3
d = T\(_2\) - T\(_1\) = 8 - 3 = 5
The general term of an A.P is:
T\(_n\) = a + (n - 1)d
⇒ T\(_n\) = 3 + (n - 1)5
= T\(_n\) = 3 + 5n - 5
∴ T\(_n\) = 5n - 2