In a past lesson, you
learned about arrays, and how they allow you to store a sequence of data under the same variable name.
In this lesson, let's use arrays to evaluate a "recurrence relation." Here is the recurrence
relation (from Salkind, 1966): $F(n+1)=\frac{2F(n)+1}{2}$, given that $F(1)=2$.
Hopefully,
you can see why this is a "recurrence relation." Suppose we wanted to find $F(2)$. Putting $n=2$
into the above relation, we'll get $F(2)=\frac{2F(1)+1}{2}$. As you can see, in order to find
$F(2)$, we need to know what $F(1)$ is. Luckily here, $F(1)$ is given to be $2$ (most recurrence
relations are given with some starting value like this). Notice that the function is defined in terms of itself--this
is called a "recursive function" and is why the relation is called a "recurrence relation."
Given all of this, your job is to evaluate $F(101)$.
Now you try. Fix the for loop and program in the recurrence relation to find F[101]!
Type your code here:
See your results here:
In this code, we've started you out by setting up the array F, and that we know F[1]=2. Fix
the for-loop to run over the proper values of n. Next program in the
recurrence relation into the F[n]= line.
When done, try this recurrence relation: $F(n)=F(n-1)+F(n-2)$, given that $F(0)=0$ and $F(1)=1$. Evaluate all $F$'s from
$n=2$ to $10$. The numbers you generate are called "Fibonacci Numbers."
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