Question

If $y=2x^3-2x^2+3x-5$, then for $x=2$ and $\Delta x=0.1$ value of $\Delta y$ is

• A. $2.002$
• B. $1.9$
• C. $0$
• D. $0.9$

Answer 1

Answer: (B)

Given, $y=2x^3-2x^2+3x-5$
$\Rightarrow \frac{dy}{dx}=6x^2-4x+3$
$\Rightarrow {\left(\frac{dy}{dx}\right)}_{x=2}=24-8+3=19$
$\because \Delta y={\left(\frac{dy}{dx}\right)}_{x=2}\Delta x$
$\Rightarrow \Delta y=19\times (0.1)$
$=1.9$