Chapter 5, Problem 8RE

To determine

To fill: The blank in the statement “If simple harmonic motion is described by $x=\left(\frac{\sqrt{2}}{2}\right)\sin \left(2t+\varphi \right)$ the phase angle $\varphi$ is ___ when the initial conditions are $x\left(0\right)=-\frac{1}{2}$ and $x^{\prime }\left(0\right)=1$”.