Use differentials to approximate the change in cost corresponding to an increase in sales (or production) of one unit. Then compare this with the actual change in cost. (Round your answers to two decimal places.) Function x-Value C = 0.075x2 + 5x + 7 x = 10 dC = dollars AC = dollars Need Help? Read It Watch It 4. [-/2 Points] DETAILS LARAPCALC10 3.8.018. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Use differentials to approximate the change in profit corresponding to an increase in sales (or production) of one unit. Then compare this with the actual change in profit. Function x-Value P = -0.1x3 + 900x - 80 X = 70 dP = dollars AP = dollars Need Help? Read It Watch It