Mathematics - Application of Derivative Question with Solution | TestHub

$y=9x^4+12x^3-36x^2+25$

Differentiating,

$\frac{dy}{dx}=36x^3+36x^2-72x$
       $=36x\left(x^2+x-2\right)$

       $=36x\left(x+2\right)\left(x-1\right)$

Sign convention for $\frac{dy}{dx}$

$\therefore S_1=\left\{-\mathrm{2,1}\right\}$ $\& S_2=\left\{0\right\}$