Question

find the domain and range of f(x)
f(x)= sq. root 81-x^2

Answer 1

domain:
sqrt(u) is valid for u>= 0

so 81 - x^2 >=0
x^2 =< 81
-9=<x=<9

range:

-(x^2) is always negative

therefore 81 - x^2 is max at x = 0
min at x = +-9
0=<f(x)=<9