Decide whether each of the following sentences is valid, satisfiable or unsatisfiable:

a) Smoke Smoke

b) Smoke Fire

c) (Smoke Fire) (Smoke Fire)

d) Smoke Fire Fire

e) ((Smoke Heat) Fire) ((Smoke Fire) (Heat Fire)

f) (Smoke Fire) ((Smoke Heat) Fire)

g) Big Dumb (Big Dumb)

h) (Big Dumb) Dumb

2) Using logical entailment, prove the distributivity of over .

3) Write the following LISP function: (circle-space r)

Calculate the area of a circle with radius r

4) Write the following LISP function: (temp-change f)

Convert temperatures in Fahrenheit degrees f to temperatures in Celsius

5) Write the following LISP function: (front-or-back l)

Return the first item of a list if it contains an even number of elements

Return the last item of a list if it contains an odd number of elements