Solution: It is given that, $f(x)=a x+b, a<0$ Suppose $x_{1}, x_{2} \in R$ and $x_{1}>x_{2}$ $\Rightarrow a x_{1}<a x_{2}$ for some $a>0$ $\Rightarrow a x_{1}+b<a x_{2}+b$ for some...
Exercise 17.1
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Prove that , where are constants and is an increasing function on .
Solution: It is given that, $f(x)=a x+b, a>0$ Suppose $x_{1}, x_{2} \in R$ and $x_{1}>x_{2}$ $\Rightarrow a x_{1}>a x_{2}$ for some $a>0$ $\Rightarrow a x_{1}+b>a x_{2}+b$ for some...
Prove that the function is increasing on if and decreasing on , if .
Solution: Case I When $a>1$ Suppose $\mathrm{x}_{1}, \mathrm{x}_{2} \in(0, \infty)$ We have, $\mathrm{x}_{1}<\mathrm{x}_{2}$ $\begin{array}{l} \Rightarrow \log _{e} x_{1}<\log _{e} x_{2} \\...
Prove that the function is increasing on .
Solution: Suppose $x_{1}, x_{2} \in(0, \infty)$ We have, $x_{1}<x_{2}$ $\begin{array}{l} \Rightarrow \log _{\mathrm{e}} \mathrm{x}_{1}<\log _{\mathrm{e}} \mathrm{x}_{2} \\ \Rightarrow...