Two waves on one string are described by the wave functions

V

$y_1=3\mathrm{.}0cos(4\mathrm{.}0x-1\mathrm{.}6t),y_2=4\mathrm{.}0sin(5\mathrm{.}0x-2\mathrm{.}0t)$

where $x$ and $y$ are in centimeters and $t$ is in seconds. Find the values of $y_1+y_2$ at the points $($a$)x=1\mathrm{.}00,t=1\mathrm{.}00$; $($b$)x=1\mathrm{.}00,t=0\mathrm{.}500$; and $($c$)x=0\mathrm{.}500,t=0.$ Note: Remember that the arguments of the trigonometric functions are in radians.