8. If $\arcsin x < \arccos x$, then the range of values for $x$ is
8. $-1 \leqslant x<\frac{\sqrt{2}}{2}$.

Draw the graphs of $y=\arcsin x$ and $y=\arccos x$. From the graphs, it can be determined that $\arcsin x<\arccos x$ if and only if $-1 \leqslant x<\frac{\sqrt{2}}{2}$.