I need help on the following problem: The depth of the water, f(x) in meters for a particular body of water is given as a function of time,x, in hours after midnight by the function f(x)=10+7.5cos(0.4x). Find f'(x). f'(x)=_____ How quickly is the tide rising or falling, in meters per hour at 6am? (Round to 4 decimal places and be sure calculator is in radians) Answer:______m/hr