Let f(x)=x2 and g(x)=x, how do you find the domain and rules of (fg)(x)?

1 Answer
Oct 26, 2017

Domain: x>0
(fg)(x)=x3 or, equivalently x32

Explanation:

f(x)g(x)=x2x ...and since
XXXXXXdivision by zero is undefined, and
XXXXXXsquare root of negative numbers are not defined for Real values
XXXwe can eliminate any values of x0
leaving us with a domain of x>0

x2x=x2×x12=x32 or
XXXXXXXXXX=(x)3 or
XXXXXXXXXX=x32