Chan Min Yi's answer to Kathy's Secondary 4 A Maths Singapore question.
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
expanding n! to n(n-1)(n-2)! is the only trick here.
substitute in numbers to visualise this if needed:
e.g. 5!=5(4)(3)(2)(1) which is also (5)(5-1)(5-2)!
substitute in numbers to visualise this if needed:
e.g. 5!=5(4)(3)(2)(1) which is also (5)(5-1)(5-2)!
Date Posted:
5 years ago
Sorry, it was n=-8 (na, n>o) not n=-7
360 Tutoring Program