D deuce New member Joined Jan 9, 2007 Messages 2 Jan 9, 2007 #1 Is foil used to multiply out (a+1)^3? If so how does it work for (a+1)(a+1)(a+1)? I tried using foil for two terms and put that answer into the third term but I can't get the answer of a^3+3a^2+3a+1. How is this done?? Thanks!!
Is foil used to multiply out (a+1)^3? If so how does it work for (a+1)(a+1)(a+1)? I tried using foil for two terms and put that answer into the third term but I can't get the answer of a^3+3a^2+3a+1. How is this done?? Thanks!!
G galactus Super Moderator Staff member Joined Sep 28, 2005 Messages 7,203 Jan 9, 2007 #2 Multiply 2 terms and then multiply the third, if that's easier. \(\displaystyle (a+1)(a+1)=a^{2}+2a+1\) Now, multiply by the other a+1: \(\displaystyle (a^{2}+2a+1)(a+1)=a^{3}+3a^{2}+3a+1\)
Multiply 2 terms and then multiply the third, if that's easier. \(\displaystyle (a+1)(a+1)=a^{2}+2a+1\) Now, multiply by the other a+1: \(\displaystyle (a^{2}+2a+1)(a+1)=a^{3}+3a^{2}+3a+1\)
