Update my answer to Exercise 1.6.

Modified are the following 3 files:

	Exercise_1.6.pdf
	Exercise_1.6.scm
	Exercise_1.6.tm

Thank you!
							Lawrence X. Amlord
							  Feb 19th, 2014
							  Fuzhou, China
Add my answer to Exercise 4.25.

Included are the following 3 files:

	Exercise_4.25.pdf
	Exercise_4.25.scm
	Exercise_4.25.tm

Thank you!
							Lawrence X. Amlord
							  Feb 19th, 2014
							  Fuzhou, China
Update my answer to Exercise 4.25.

Included are the following 2 files:

	Exercise_1.6.pdf
	Exercise_1.6.tm

Thank you!
							Lawrence X. Amlord
							  Feb 19th, 2014
							  Fuzhou, China
Add my answer to Exercise 4.26.

Included are the following 2 files:

	Exercise_4.26.pdf
	Exercise_4.26.tm

Thank you!
							Lawrence X. Amlord
							  Feb 19th, 2014
							  Fuzhou, China