$遞減型\; f(x)=k\cdot a^x $

$ =x\left[\left (log\;8+log\;3\right )-\left( 2\;log\;5  \right)  \right]$

$ =x\left( 2\;log\;3-1  \right)  $

$ =x\left( log\;2^3-1  \right)  $

$ =x\left( 0.9030+0.4771-2\times 0.6990  \right)  $

$ =-0.0179\;x $

$ =x\left( 2\times 0.4771-1  \right)  $

$ =-0.0458\;x $

$ =x\left( 3\times0.3010-1  \right)  $

$ =-0.0970\;x $

假設最少需要重疊\;x\;塊玻璃板

n = 9 (slider from 2 to 9, step 1)
list1: {4, 10, 20}
k = 2 (slider from 1 to 3, step 1)
b = Element(list1, k)
list2: {0.96, 0.9, 0.8}
list3: {"", "0.3010", "0.4771", "0.6020", "0.6990", "0.7781", "0.8451", "0.9030", "0.9542"}
list4: {0, 0.301, 0.4771, 0.602, 0.699, 0.7781, 0.8451, 0.903, 0.9542}
list5: {0.0179, 0.0458, 0.097}
step = 0 (slider from 0 to 11, step 1)
text11: "$ ⇒x= " + (LaTeX[floor(Element[list4, n] / Element[list5, k]) + 1]) + "$"
text03: "$ ⇒" + (LaTeX[FractionText[1 / n]]) + "=\left(    " + (LaTeX[FractionText[Element[list2, k]]]) + "\right)^x $"
text06: "$ ⇒-" + (LaTeX[Element[list3, n]]) + " =x\left( log\;" + (LaTeX[If[k ≟ 1, 24, If[k ≟ 2, 9, 8]]]) + "-log\;" + (LaTeX[If[k ≟ 1, 25, 10]]) + "  \right) $"
text04: "$ ⇒log\;" + (LaTeX[FractionText[1 / n]]) + "=log\left( " + (LaTeX[FractionText[Element[list2, k]]]) + "  \right) ^x $"
text05: "$⇒-log\; " + (LaTeX[n]) + "=x\cdot log\; " + (LaTeX[FractionText[Element[list2, k]]]) + "$"
text10: "$ ⇒x=\frac{-" + (LaTeX[Element[list3, n]]) + "}{" + (LaTeX[If[k ≟ 1, "-0.0179", If[k ≟ 2, "-0.0458", "-0.0970"]]]) + "} =\frac{" + (LaTeX[Element[list4, n]]) + "}{" + (LaTeX[Element[list5, k]]) + "}=" + (LaTeX[Element[list4, n] / Element[list5, k]]) + "$"
A = Corner(4)
text02: "$ " + (LaTeX[FractionText[1 / n]]) + "=(1-" + (LaTeX[b]) + "%) ^x$"
t_Q: "已知光線通過一塊玻璃板，\;光線的強度減弱\;" + (LaTeX[b]) + "%，\;若要使通過光線的強度減弱到原來強
\\度的\;" + (LaTeX[FractionText[1 / n]]) + "\;以下，\;則至少需要重疊幾塊玻璃板？
\\Sol："