$$\text { Show that } \int _ { 0 } ^ { x } - 5 \cos 2 x d x = 0 \text { by interpreting the definite integral geometrically. }$$

$$\text { Show that } \int _ { 0 } ^ { x } - 5 \cos 2 x d x = 0 \text { by interpreting the definite integral geometrically. }$$