John M. answered 02/03/21
Math Teacher/Tutor/Engineer - Your Home, Library, MainStreet or Online
You could let x = sin(t) then 3x2 +9x + 4 = 0
Solving by graphing or algebraically,
then x = -0.54257 between
So Sin-1 (t) = -0.54257 between [-pi/2, pi/2], then t = -0.5735 radians = -32.8588º