Jack and Jill are looking at a 25-foot tree. Jack sees the top of the tree at an angle of elevation of 20º and Jill sees the top of the tree at an angle of elevation of 30°. How far apart are Jack and Jill?
(TWO DECIMAL PLACES)

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).