To find the rotation angle at $\mathrm{B}$, add the twist angle in shaft segment $\left(1\right)$ to the rotation angle at $\mathrm{A}$:

${\mathrm{\varphi }}_{\mathrm{B}}={\mathrm{\varphi }}_{\mathrm{A}}+{\mathrm{\varphi }}_1$

$$\begin{gathered} =0+0.0158 \mathrm{rad} \\ =0.0158 \mathrm{rad} \end{gathered}$$

To find the rotation angle at $\mathrm{C}$, add the twist angle in shaft segment $\left(2\right)$ to the rotation angle at $\mathrm{B}$:

${\mathrm{\varphi }}_{\mathrm{C}}={\mathrm{\varphi }}_{\mathrm{B}}+{\mathrm{\varphi }}_2$

$$\begin{gathered} =0.0158+(-0.0237) \\ =\mathbf{-}\mathbf{0}\mathbf{.}\mathbf{0079}\mathbf{ }\mathbf{rad} \end{gathered}$$