$\displaystyle f(z) = \frac{z+2}{2 }$ evaulate $\displaystyle \int c f(z) dz$ when $\displaystyle C $is the semicircle $\displaystyle z=2{e}^{ i\theta } , 0 \leqslant \theta \leqslant \pi$

I am not getting what my lecturer gets, ill show you what ive done.