The speed of sound traveling through ocean water is a function of temperature, salinity, and pressure. It has been modeled by the function
C = 1449.2 + 4.6T - 0.055T2 + 0.00029T3 + (1.34 - 0.01T)(S - 35) + 0.016D
where C is the speed of sound (in meters per second), T is the temperature (in degrees Celsius), S is the salinity (the concentration of salts in parts per thousand, which means the number of grams of dissolved solids per 1000 g of water), and D is the depth below the ocean surface (in meters). Compute ∂C/∂T, ∂C/∂S, and ∂C/∂D when T = 10 ?, S = 35 parts per thousand, and D = 100 m. Explain the physical significance of these partial derivatives.