A sniper providing cover for the ground team during military operation can shoot in all directions from a fixed point O. If the killing range of his gun is 400m, the fatal injury range is 600m and the mild injury range is 800m. (I) Calculate the areas the enemy troop must avoid in order not to get killed or fairly injured by the sniper's gunshot.

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Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.

Idon’t see a picture