How do you evaluate e^(lny)elny?

1 Answer
Dec 16, 2016

This expression evaluates ro yy for every positive real number yy. See explanation.

Explanation:

f(y)=e^yf(y)=ey and g(y)=lnyg(y)=lny are inverse functions, so both compositions: e^lnyelny and lne^ylney evaluate to yy in all their domains.

Since lnylny is only defined for y>0y>0 the domain of the givenexpression is also y>0y>0.

So the expression e^lnyelny is equal to yy for all positive real numbers yy