A graphing calculator is recommended. A crystal growth furnace is used in research to determine how best to manufacture crystals used in electric components for the space shuttle. For proper growth of the crystal, the temperature must be controlled accurately by adjusting the input power. Suppose the relationship is given by T(w) = 0.1w2 + 2.154w + 20 where T is the temperature in degrees Celsius and w is the power input in watts.