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 COS 341, October 15, 1997

Handout Number 10

Homework Set 5

Reading Assignments Read Chapter 11.

Written Assignments Do exercises 1, 7 and 11 in Section 7.8.

Special Problem 1 (to be counted as 1 exercise) Let n be any positive integer. Evaluate

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Your answer should be a closed-form expression of n.

Special Problem 2 (to be counted as 1 exercise) Let n>1 be any integer. The road map of a certain town forms a tex2html_wrap_inline91 grid (two East-West streets of length (n-1) each, and n North-South streets of length 1 each). All the roads are two-way. If you want to go from the south-west corner point Q to the north-east corner point W, how many different routes can you take without traversing the same segment twice? Give your answer as a closed-form expression of n.

Remarks Let g(n) be this number. Then g(2)=2, g(3)=4.

Special Problem 3 (counted as 1 exercise) Solve the following recurrence relation: tex2html_wrap_inline109 , and for n>1,

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Andrew Yao
Sat Oct 11 17:18:07 EDT 1997