Hi,

I am trying to solve this question :

Exercise: The N'th triangular number is defined to be 1 + 2 + 3 + ... + N. Alternatively, we could give a recursive definition of triangular number as follows:

T(n) = 1 if n = 1

T(n) = n + T(n-1) if n > 1

Use the recursive definition to help you implement a linearly recursive function (triangular N) that returns the N'th triangular number. Enter your function definition into a text file. Then load it into LISP. Evaluate (triangular 6).

Below is my code :

(defun triangle (N)

"Compute the Triangular Number of N."

(if (= N 1)

1

(+ N (triangular (- N 1)))))

When I loaded it into the Debug Window using (load "CallTriangle") , it says Loading C:\acl82express\CallTriangle.cl. How do I evaluate (triangular 6) ?

Thanks