Find nth Term of Series & Sequence: Un = 4(n-1)-1

[ghostbuster25]

Just a check of my work please,

The topic is series and sequence,
Question:
The sequence u₁, u₂, u₃,... where u₁ is defined by u₁=2 and U_n+1 =u_n+4

Find the n^th term, u_n, of the sequence.

I got the answer,

u₁=-1
u₂=-1+4= 3
u₃= 3+4 = 7

So:
u_n = 4(n-1)-1

This seems to work but not sure if it correct

 

[Bohrok]

u₁ = 2, not -1, so continuing the pattern,
u₂ = 2 + 4 = 6
u₃ = 6 + 4 = 10

 

[ghostbuster25]

sorry i made a mistake in the question part, it is supposed to read u₁=-1

 

[Bohrok]

In that case, your formula is right (you could also write it as u_n = 4n - 5).