Next, the angles of twist in shafts $\left(1\right)$ and $\left(2\right)$ can be computed. The rotation angle at $\mathrm{D}$, however, will not simply be the sum of ${\mathrm{\varphi }}_1$ and ${\mathrm{\varphi }}_2$ in this instance. The gear rotations caused by the twisting of shaft $\left(1\right)$ must be taken into account before we can determine the final rotation angle at $\mathrm{D}$.