participation activity 9.7.1: selecting a pre...

# Explanation: ## Step1: Analyze "Compute the log base 2 of a number" The logarithm $\log_2(x)$ is only defined for $x>0$. So the pre - condition is "The input is a real number $x$ such that $x > 0$". ## Step2: Analyze "Determine whether a sequence of numbers is increasing" We need a positive integer $n$ to represent the number of elements in the sequence and the sequence of $n$ numbers $a_1,\cdots,a_n$. So the pre - condition is "The input variables are $n$, a positive integer, and a sequence of $n$ numbers $a_1,\cdots,a_n$". ## Step3: Analyze "Compute the cube root of a number" The cube root $\sqrt[3]{x}$ is defined for all real numbers $x$. So the pre - condition is "The input is a real number $x$". ## Step4: Analyze "Multiply two numbers" We need two real numbers $x$ and $y$ to perform the multiplication. So the pre - condition is "The input variables $x$ and $y$ are two real numbers". # Answer: Compute the log base 2 of a number: The input is a real number $x$ such that $x > 0$. Determine whether a sequence of numbers is increasing: The input variables are $n$, a positive integer, and a sequence of $n$ numbers $a_1,\cdots,a_n$. Compute the cube root of a number: The input is a real number $x$. Multiply two numbers: The input variables $x$ and $y$ are two real numbers.