SOLUTION
We want to write an equation that describes the pattern on the table
Number of disks is taken as x-values and minimum number of moves is taken as y-values
So since it's a square function, let's assume it takes the form
[tex]y=ax^2-bx+c[/tex]
plotting the table in a graphing calculator, we have
From the image above, we have that
[tex]a=1.5,b=2.9,c=2.5[/tex]
Substituting the values we have
[tex]\begin{gathered} y=ax^2-bx+c \\ y=1.5x^2-2.9x+2.5 \end{gathered}[/tex]
So, when x is 1, we have
[tex]\begin{gathered} y=1.5x^2-2.9x+2.5 \\ y=1.5(1)^2-2.9(1)+2.5 \\ y=1.5-2.9+2.5 \\ y=1.1\cong1 \\ \end{gathered}[/tex]
So, it works for 1.
Assume it works for x = 2, let us try 3, we have
[tex]y(3)=y(2+1)[/tex]
So,
[tex]\begin{gathered} y(k+1)=1.5(k+1)^2-2.9(k+1)+2.5 \\ y(k+1)=1.5(k^2+2k+1)-2.9(k+1)+2.5_{} \\ y(k+1)=1.5k^2+3k+1.5-2.9k-2.9+2.5 \\ y(k+1)=1.5k^2+3k+1.5-2.9k-0.4 \end{gathered}[/tex]
So, from
[tex]\begin{gathered} y(3)=y(2+1) \\ k=2 \end{gathered}[/tex]
substituting k for 2, we have
[tex]\begin{gathered} y(k+1)=y(3)=1.5(2)^2+3(2)+1.5-2.9(2)-0.4 \\ =6+6+1.5-5.8-0.4 \\ =7.3\cong7 \end{gathered}[/tex]
So, 7.3 is approximately 7,
Hence the equation
[tex]y=1.5x^2-2.9x+2.5[/tex]
works to describe this pattern.
So, the equation is
[tex]y=1.5x^2-2.9x+2.5[/tex]