Mathematics

Problem

A particle moves according to

s(t)=4t^{3}-15t^{2}+6

metres. At what time is its instantaneous velocity

12\,\text{m/s}

? a)

\dfrac{5+\sqrt{33}}{4}\,\text{s}

\dfrac{5+\sqrt{41}}{4}\,\text{s}

\dfrac{5}{2}\,\text{s}

\dfrac{5+\sqrt{41}}{2}\,\text{s}