Find the value of $sin \left( \dfrac{π}{2} + cos^{-1} \dfrac{1}{\sqrt{5}} \right) $

The correct answer is $\dfrac{1}{\sqrt{5}}$

$sin \left( \dfrac{π}{2} + cos^{-1} \dfrac{1}{\sqrt{5}} \right) $

= $cos \left( cos^{-1} \dfrac{1}{\sqrt{5}} \right) $

= $\dfrac{1}{\sqrt{5}}$