The number of traffic fatalities per hundred million vehicles is approximated by f(x)=1/squareroot x+1 where x stands for five year intervals since...

The number of traffic fatalities per hundred million vehicles is approximated by f(x)=1/squareroot x+1 where x stands for five year intervals since 1985. Find f'(4) and interpret your answer. Reference units. Use a complete sentence. show all work.