A $2\mathrm{.}80$ kg mass on a spring has displacement as a function of time given by the equation

x$($t$)=(7\mathrm{.}40$cm$)$cos$[(4\mathrm{.}16$rad$/$s$)$t$2\mathrm{.}42$rad$].$ Find the force constant of the spring. Find the position of the mass at t$=1\mathrm{.}00$s