Let `f(x)=(x-1)/(x^(2))` then which of the following is correct?

Let f(x)=(x-1)/(x^(2)), then which of the following is incorrect?

If f(x)=(x)/(x^(2)-1), then which of the following is/are correct-

Let f(x)=tan^(-1)((sqrt(1+x^(2))-1)/(x)) then which of the following is correct :

Let f(x)=tan^(-1)((sqrt(1+x^(2))-1)/(x)) then which of the following is correct :

Let f(x)=tan^(-1)((sqrt(1+x^(2))-1)/(x)) then which of the following is correct :

if f(x)=|1-x|,1<=x<=2, and g(x)=f(x)+b sin((pi x)/(2)) then which of the following is correct

If f(x)=|x|+|x-1| , then which one of the following is correct?

If f(x)=|x|+|x-1| , then which one of the following is correct?

Let f(x) be a differentiable function. If h(x)=(1)/(3) {f(x)}^(3)+{f(x)}^(2)+f(x)+(1)/(3) then which one of the following is correct ?