高一数学化简题，我打的详细了些，所以显得有些乱

-sec^2(x)+2cot^2(x)
过程：
1/cosx*√[1+sin^2(x)/cos^2(x)]+2/tanx*√[-1+1/sin^2(x)]

=1/cosx*√[1/cos^2(x)]+2/tanx*√[[-sin^2(x)+1]/sin^2(x)]

=1/cosx*|1/cosx|+2/tanx*√[[-sin^2(x)+1]/sin^2(x)]

x是第三象限角 |cosx|=-cosx |cotx|=cotx

=(1/cosx)*(-1/cosx)+2/tanx*√[cos^2(x)/sin^2(x)]

=-[1/cos^2(x)]+2/tanx*√cot^2(x)

=-sec^2(x)+2*cotx|cotx|

=-sec^2(x)+2*cot2^(x)

1/cosx*√[1+sin^2(x)/cos^2(x)]+2/tanx*√[-1+1/sin^2(x)]
=1/cosx*√(1/cos^2(x))+2/tanx*√(cot^2(x))
=-1/cos^2(x)+2cot^2(x)

没看明白是什么意思