The maximum value of the function f(x)=sinx1-cos2x+cosx1-sin2x+tanxsec2x-1+cotxcosec2x-1
wherever it is defined is k. Then |k| is
(1)
f(x)=sinx1-cos2x+cosx1-sin2x+tanxsec2x-1+cotxcosec2x-1
=sinx|sinx|+cosx|cosx|+tanx|tanx|+cotx|cotx|={4,x∈1st quadrant-2,x∈2nd quadrant0,x∈3rd quadrant-2,x∈4th quadrant
f(x)max=4