Answer
$\dfrac{1+\sqrt 3}{2}$
Work Step by Step
Recall the identity: $(f+g) (x)=f(x)+g(x)$
Let us consider that $f(x)=\sin x $ and $g(x)=\cos x$
Now, $(f+g) (30^{\circ})=f(30^{\circ})+g (30^{\circ})$
We know from the unit circle that $\sin (30^{\circ}) =\dfrac{1}{2}$ and $\cos (30^{\circ})=\dfrac{\sqrt 3}{2}$
Thus, we have: $(f+g) (30^{\circ})=\sin (30^{\circ})+\cos (30^{\circ}) \\= \dfrac{1}{2} + \dfrac{\sqrt 3}{2} \\=\dfrac{1+\sqrt 3}{2}$
