Question

[Julian Edward]

cho hàm số \(f\left(x\right)=2x^2+1\). đặt \(y=f\left(x\right)-f'\left(x\right)\). tìm x để \(y'\left(x\right)=0\)?

Answer 1

[Nguyễn Việt Lâm]

\(f'\left(x\right)=4x\Rightarrow y=2x^2+1-4x\)

\(y'\left(x\right)=4x-4=0\Rightarrow x=1\)