Solution for Section 3.5 Question 4

4. Suppose that n is an even integer. We need to show that lceil.jpg (551 bytes)n / 2rceil.jpg (532 bytes) = lfloor.jpg (533 bytes)n / 2rfloor.jpg (530 bytes).

Proof Since n is an even integer, n = 2k   for some integer k. 

Left-hand side: lceil.jpg (551 bytes)n / 2rceil.jpg (532 bytes) = lceil.jpg (551 bytes)2k / 2rceil.jpg (532 bytes) = lceil.jpg (551 bytes)krceil.jpg (532 bytes) = k  (since the ceiling of an integer is equal to that integer).
Right-hand side: lfloor.jpg (533 bytes) n / 2 rfloor.jpg (530 bytes)= lfloor.jpg (533 bytes) 2k / 2 rfloor.jpg (530 bytes)= lfloor.jpg (533 bytes)krfloor.jpg (530 bytes)= k  (since the floor of an integer is equal to that integer).

Thus lceil.jpg (551 bytes)n / 2rceil.jpg (532 bytes) = lfloor.jpg (533 bytes)n / 2rfloor.jpg (530 bytes).

Back to Section 3.5