Show that the function given by $f(x) = 3x + 17$ is strictly increasing on $R$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(A) Let $x_{1}$ and $x_{2}$ be any two real numbers such that $x_{1} < x_{2}$.
Multiplying both sides by $3$,we get $3x_{1} < 3x_{2}$.
Adding $17$ to both sides,we get $3x_{1} + 17 < 3x_{2} + 17$.
This implies $f(x_{1}) < f(x_{2})$.
Since $x_{1} < x_{2}$ implies $f(x_{1}) < f(x_{2})$ for all $x_{1}, x_{2} \in R$,the function $f(x) = 3x + 17$ is strictly increasing on $R$.
Alternative Method:
Find the derivative of the function: $f'(x) = \frac{d}{dx}(3x + 17) = 3$.
Since $f'(x) = 3 > 0$ for all $x \in R$,the function $f(x)$ is strictly increasing on $R$.

Explore More

Similar Questions

In which interval is the function $f(x) = x^2 - x + 1$ not monotonic?

Let $R^* = R - \left\{ (2k - 1) \frac{\pi}{2} \mid k \in I \right\}$. The function $f: R^* \rightarrow R$ is defined as $f(x) = \tan x - x$,then $f(x)$ is

The function $f(x) = \tan^{-1}(\sin x + \cos x)$ is an increasing function in

Prove that the logarithmic function $f(x) = \log x$ is strictly increasing on $(0, \infty).$

If $f(x) = \sin x - \frac{x}{2}$ is an increasing function,then:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo