Another question from O Level Additional Mathematics (A-Math).
lijun(: said...
hey. i just want to clarify something that i'm not very sure of.
is nCr x r! = nPr ??
By definition,
nCr = nPr/r!
Well, I never remember this 'rule'
For example, find the number of ways to form a 3 letter word from a,b,c,d,e
Student #1:
5C1*4C1*3C1
Student #2:
5P3
Both answers are correct though different approaches are taken, so no need to remember the 'rule'
:)
Ai Ling Ong
Hi, I'm Ai Ling Ong. I enjoy coaching students who have challenges with understanding and scoring in 'O' Level A-Maths and E-Maths. I develop Math strategies, sometimes ridiculous ideas to help students in understanding abstract concepts the fast and memorable way. I write this blog to share with you the stuff I teach in my class, the common mistakes my students made, the 'way' to think, analyze... If you have found this blog post useful, please share it with your friends. I will really appreciate it! :)
ok. thanks! (: