What is the domain and range of y= -x/(x^2-1)y=xx21?

1 Answer
Jan 28, 2018

x inRR,x!=+-1
y inRR,y!=0

Explanation:

The denominator of y cannot be zero as this would make y undefined. Equating the denominator to zero and solving gives the values that x cannot be.

"solve "x^2-1=0rArr(x-1)(x+1)=0

rArrx=+-1larrcolor(red)"excluded values"

"domain is "x inRR,x!=+-1

"divide terms on numerator/denominator by "x^2

y=(x/x^2)/(x^2/x^2-1/x^2)=(1/x)/(1-1/x^2)

"as "xto+-oo,yto0/(1-0)

rArry=0larrcolor(red)"excluded value"

"range is "y inRR,y!=0
graph{-x/(x^2-1) [-10, 10, -5, 5]}