# SICP exercises 1.2 cont. 2

**Posted:**January 6, 2013

**Filed under:**Improving, SICP Leave a comment

Again only one problem. I’ll need to be more motivated.

**1.12**

The following pattern of numbers is called Pascal’s triangle.

*The numbers at the edge of the triangle are all 1, and each number inside the triangle is the sum of the two numbers above it.35 Write a procedure that computes elements of Pascal’s triangle by means of a recursive process.
*

(define (pascal row nth) (cond ((or (= nth row) (= nth 1)) 1) ((< nth 0) 0) (else (+ (pascal (- row 1) nth) (pascal (- row 1) (- nth 1))))))

Advertisements