已知集合A={x|x^2≥1/4}集合B={x|x=(1-cosx)/sinx,-π/2＜x＜π/2}求A交B

Question

已知集合A={x|x^2≥1/4}集合B={x|x=(1-cosx)/sinx,-π/2＜x＜π/2}求A交B

Answer 1

x^2》1/4
x》1/2或x《-1/2
A={x|x》1/2或x《-1/2}
x=[cos(x/2)*cos(x/2)+sin(x/2)*sin(x/2)-cos(x/2)*cos(x/2)+sin(x/2)*sin(x/2)]/[2sin(x/2)cos(x/2)]
=tan(x/2)
-π/4＜x/2＜π/4
-1