Question

Let $y=f\left(x\right)=2x^2-3x+2$. The differential of $y$ when $x$ changes from $2$ to $1.99$ is

• A. $0.01$
• B. $0.18$
• C. $-0.05$
• D. $0.07$

Answer 1

The correct option is C $-0.05$

$\delta y=f^{\prime }\left(x\right).\delta x,\text{changes from 2 to 1.99}\Rightarrow \delta x=-0.01\Rightarrow \delta y=(4x-3)\delta x\Rightarrow \delta y=(4\times 2-3)(-0.01)=-0.05$