which of the following functions has an average rate of change equal to zero over any interval?\na…

which of the following functions has an average rate of change equal to zero over any interval?\na. $f(x)=x^{2}$\nb. $f(x)=7$\nc. $f(x)=x$\nd. $f(x)=\\frac{1}{x}$
Answer
Explanation:
Step1: Recall the formula for average rate of change
The average rate of change of a function (y = f(x)) over the interval ([a,b]) is given by (\frac{f(b)-f(a)}{b - a}).
Step2: Analyze option b
Let (f(x)=7). Then for any interval ([a,b]), (f(a) = 7) and (f(b)=7). So (\frac{f(b)-f(a)}{b - a}=\frac{7 - 7}{b - a}=0).
Step3: Analyze option a
Let (f(x)=x^{2}). Then (\frac{f(b)-f(a)}{b - a}=\frac{b^{2}-a^{2}}{b - a}=\frac{(b - a)(b + a)}{b - a}=b + a\neq0) (unless (a=-b) but not for any interval).
Step4: Analyze option c
Let (f(x)=x). Then (\frac{f(b)-f(a)}{b - a}=\frac{b - a}{b - a}=1\neq0).
Step5: Analyze option d
Let (f(x)=\frac{1}{x}). Then (\frac{f(b)-f(a)}{b - a}=\frac{\frac{1}{b}-\frac{1}{a}}{b - a}=\frac{\frac{a - b}{ab}}{b - a}=-\frac{1}{ab}\neq0).
Answer:
B. (f(x) = 7)