


			       6.001 Spring 1993
			      Problem Set 5 Errata

     We blew a few spots on Problem Set 5 handout.  Please incorporate the
     following clarifications and notes.

     PreLab Problem 5.3a: Define the predicate EQU-RAT? that tests whether
     two rationals are equal.

     PreLab Problem 5.7a: (Exercise 2.63 in notes) Note that "univariate
     polynomial" means a polynomial whose coefficients are numbers or
     rationals constructed with integer numerators and denominators.

     Lab Problem 5.7b: Of course, /POLY as written in Exercise 2.63 returns
     both a quotient and a remainder.  You must install a procedure which
     extracts only the quotient part of this as the polynomial entry for
     generic DIV.

       Test (/POLY (contents p3) (contents p4)) -- check that the quotient
       and the remainder are correct.

       Also test (div p3 p4) -- you should get the quotient.

     PreLab Problem 5.8a: (Exercise 2.66) 
       Note "ordinary" gcd means Scheme's built-in GCD procedure.
       Note your generic GREATEST-COMMON-DIVISOR will only be generic for
	Scheme numbers and polynomials with numerical coefficients.

     Lab Problem 5.8b: Do it after 5.9 ... numbering is wrong.

     PreLab Problem 5.9: (Exercise 2.67) This exercise incorrectly asks you
     about the examples in Exercise 2.66.  It should really refer to the
     examples in 2.67.

     Prelab Problem 5.10: (Exercise 2.68) Note that this algorithm is
     intended for polynomials with integer coefficients only.

     Problem 5.11: There is a typo; it should read:

       (define rf1 (create-rational p7 p8))
       (define rf2 (create-rational p9 p10))
       (add rf1 rf2)
