Question

how to derive marginal utility of income?

Answer 1

Google is a wonderful place to start!

http://www.google.com/search?q=how+to+derive+marginal+utility+of+income&oq=how+to+derive+marginal+utility+of+income&aqs=chrome..69i57j0.3163j0j7&sourceid=chrome&espv=210&es_sm=119&ie=UTF-8