1. ## Sequences

Gven Un=6n-3-a, where a is constant,to find the recurrence relation of the form Un+1=f(Un),what is my first step?any suggestion?i dont even know how to start

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2. ## Re: Sequences

Try $U_{n+1}-U_n=6(n+1)-3-a-(6n-3-a)$

Add $U_n$ to both sides and simplify.

3. ## Re: Sequences

Originally Posted by goldsomecriss
Gven Un=6n-3-a, where a is constant,to find the recurrence relation of the form Un+1=f(Un),what is my first step?any suggestion?i dont even know how to start
As I read this question, $U_n=6n-3-a.~\forall n$.
\begin{align*}U_1&=3-a\\U_2&=9-a\\U_3&=15-a\end{align*}.

So\begin{align*} U_{n+1} &= 6(n+1)-3-a \\ &=(6n-3-a)+6\\&=U_n+6\end{align*}

4. ## Re: Sequences

Originally Posted by Plato
As I read this question, $U_n=6n-3-a.~\forall n$.
\begin{align*}U_1&=3-a\\U_2&=9-a\\U_3&=15-a\end{align*}.

So\begin{align*} U_{n+1} &= 6(n+1)-3-a \\ &=(6n-3-a)+6\\&=U_n+6\end{align*}
thanks

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