The wind-chill index is modeled by the function W − 13.12 1 0.6215T 2 11.37v 0.16 1 0.3965Tv 0.16 where T is the temperature sin 8Cd and v is the wind speed sin kmyhd. The wind speed is measured as 26 kmyh, with a possible error of 62 kmyh, and the temperature is measured as 2118C, with a possible error of 618C. Use differentials to estimate the maximum error in the calculated value of W due to the measurement errors in T and v.