Fluid Mechanics in SWCE

For a linear boundary layer velocity profile $\frac{u}{U_\infty} = \frac{y}{\delta}$, displacement thickness $\delta^* = \int_0^\delta (1 - y/\delta) dy = \left[y - \frac{y^2}{2\delta}\right]_0^\delta = \frac{\delta}{2}$. If boundary layer thickness is $\delta = 10\text{ mm}$, displacement thickness $\delta^*$ in mm is: