If f:R→R  be given byf(x)=(x+1)2−1,x≥−1  then the set of values of x for which f(x)=f−1x  is given by

y=(x+1)2−1 ⇒(x+1)2=y+1 (x+1)=y+1 x=y+1−1 f−1(x)=x+1−1 Here f=f−1 (x+1)2−1=x+1−1 (x+1)2=x+1