∫Cos[x]/(1 + Sin[x]^2) \[DifferentialD]x

Plot[ArcTan[Sin[x*(Pi/180)]], {x, 0, 360}]

(∫_0^2)(∫_((x/2))^1) (E^(-(y^2))) \[DifferentialD]y \[DifferentialD]x

(∫_0^1)(∫_0^(2  y))(E^(-(y^2))) \[DifferentialD]x \[DifferentialD]y