standard_description: Write arithmetic and geometric sequences both recursively and with an explicit formula, use them to model situations, and translate between the two forms.
problem_activity: Task
Complete the table below. Is $\Delta x$ a constant?  If so, what constant is it? What do you notice about the 3rd column of the table?
{"table": [{"tbody": [{"tr": [{"th": [{"_value": "$x$"}, {"_value": "$f(x)=128\\cdot \\left({\\frac {1}{2}}\\right)^x$"}, {"_value": "Successive quotients"}]}, {"td": [{"_value": "0"}, {"_value": "128"}, {"_value": "----"}]}, {"td": [{"_value": "1"}, {"_value": "64"}, {"_value": "$\\frac{f(1)}{f(0)}=\\frac {64}{128} = \\frac{1}{2}$"}]}, {"td": [{"_value": "2"}, {}, {"_value": "$\\frac{f(2)}{f(1)}=$"}]}, {"td": [{"_value": "3"}, {}, {}]}, {"td": [{"_value": "4"}, {}, {}]}]}]}]}
Complete the table below. Is $\Delta x$ a constant?  If so, what constant is it? What do you notice about the 3rd column of the table?
{"table": [{"tbody": [{"tr": [{"th": [{"_value": "$x$"}, {"_value": "$f(x)=128\\cdot \\left({\\frac {1}{2}}\\right)^x$"}, {"_value": "Successive quotients"}]}, {"td": [{"_value": "0"}, {"_value": "128"}, {"_value": "---"}]}, {"td": [{"_value": "2"}, {"_value": "32"}, {"_value": "$\\frac{f(2)}{f(0)} = \\frac {32}{128} = \\frac{1}{4}$"}]}, {"td": [{"_value": "4"}, {}, {"_value": "$\\frac{f(4)}{f(2)}=$"}]}, {"td": [{"_value": "6"}, {}, {}]}, {"td": [{"_value": "8"}, {}, {}]}]}]}]}
Let $f(x)=a \cdot b^x$. Let $x_0$ be any particular $x$-value. Show that if $x_0$ is increased by a constant, $\Delta x$, the successive quotient  $$\frac{f(x_0+ \Delta x)}{f(x_0)}$$ is always the same no matter what $x_0$ is.
Is b) an example of the result of c)? Explain.


aligns: no