Question

${lim}_{y\to 1}(\frac{1}{y^2-1}-\frac{2}{y^4-1})=$

• A. $\frac{1}{2}$
• B. $\frac{1}{3}$
• C. $\frac{1}{4}$
• D. $0$

Answer 1

The correct option is A $\frac{1}{2}$

${lim}_{y->1}(\frac{1}{y^2-1}-\frac{2}{y^4-1})$

=>${lim}_{y->1}(\frac{1}{y^2-1}-\frac{2}{(y^2-1)(y^2+1)})$

=>${lim}_{y->1}\left(\frac{y^2-1}{(y^2-1)(y^2+1)}\right)$

=> ${lim}_{y->1}\left(\frac{1}{y^2+1}\right)$

=>$\frac{1}{2}$