ทดลองแก้ๆๆๆ f ( n ) = { n / 2 , if n is even 3 n + 1 , if n is odd {\displaystyle f(n)={\begin{cases}n/2,&{\mbox{if }}n{\mbox{ is even}}\\3n+1,&{\mbox{if }}n{\mbox{ is odd}}\end{cases}}} f ( x ) = ( a + b ) 2 = a 2 + 2 a b + b 2 {\displaystyle {\begin{aligned}f(x)&=(a+b)^{2}\\&=a^{2}+2ab+b^{2}\\\end{aligned}}}
