Lesson Review

• formula to find the t (n) number of positive divisors of a positive number n
• A proper divisor of a positive integer is any divisor of other than. itself
• Any positive perfect square has an odd number of positive divisors;
• If m and n are any two positive integers such that gcd(m,n)=1, then t(mn)=t(m)*t(n)
• product of the positive divisors of a positive integer n: Pn=N^(t(n)/2)

Homework

• P.92 Ex 5.2.1(e)(f)(i)(l); 5.2.3
• P.98 Ex 5.3.1, 5.3.4, 5.3.7, 5.3.9
• P.101 Ex 5.4.3, 5.4.4, 5.4.6
• P.104 Ex 5.17
• P.105 Ex 5.21, *5.26, *5.27

Other Resources

• https://www.math.upenn.edu/~deturck/m170/wk2/numdivisors.html
• http://mathonline.wikidot.com/the-number-of-positive-divisors-of-an-integer
• https://www.youtube.com/watch?v=Be5fd7h4aQo
• https://www.youtube.com/watch?v=IeyVdRHOPzc

Ch.5 is not easy. If you have any questions, please feel free to reach out and Ms. Li will be happy to help. Remember to turn in your homework by next Sat night, so that I can grade and give it back to you before our class. Next week, we will spend some time discussing the leftover problems in Ch.5.

Take care and look forward to learning Ch. 6 with all of you next Sunday.

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