Determine intervals where solutions are sure to exist 1) y^(4)+4y'''+3y=t
2) t(t -1)y^(4) + e^ty'' + 4t^2y = 0
3) (x-1)y^(4)+(x+1)y''+(tanx)y=0

At his new job, jeremiah can choose an hourly rate of $9 plus a $50 weekly bonus for opening the store, or an hourly rate of $10 per hour with no opening bonus. the equations model his salary options. y = 9x + 50 y = 10x

What is the range? can’t seem to find it out

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters