What is the range of the function

r(x)=1/(1-x)^2? Express your answer in interval notation. Thank you!

at x=1, r is undefined (∞)

As x gets huge, r-> 0
The denominator is always positive,

So, the range is (0,∞)

See the graph at

http://www.wolframalpha.com/input/?i=1%2F%281-x%29^2