1. The problem statement, all variables and given/known data R=1/(.55/c+.45/h) find partial equations respect to c. and respect to h use implicit function differentiation of the reciprocal of R to answer what is the differential change in R when c=20 h=30 and c changes to 21 2. Relevant equations is there any way to make R easier? i said that R=ch/(.55h+.45c) which was the best i could do. Is there any other way to make R easier? 3. The attempt at a solution i got the partial equations if the R=ch/(.55h+.45c) is right. but im not sure how to use implicit or what implicit is. i just found it normally. WHen it says what is the differential change in R when c=20 and h=3 and c changes to 21. do i just substitude them to the partial differentials and add them?