If \( a=\sin^{-1}(\sin 5)) \) and \( b=\cos^{-1}(\cos 5)) \), then \( a^{2}+b^{2} \) is equal to:
\( 8\pi^{2}-40\pi+50 \)
\( 4\pi^{2}+25 \)
\( 4\pi^{2}-20\pi+50 \)
\( 25 \)