第十题!help!SOS!
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第十题!help!SOS!
第十题!help!SOS!
第十题!help!SOS!
(1+sina-cosa)/sina*(1+sinb-cosb)/sinb
=(1+(1-cosa)/sina)*(1+(1-cosb)/sinb)
=(1+tan(a/2))+(1+tan(b/2))
=1+tan(a/2)+tan(b/2)+tan(a/2)tan(b/2)=2
tan(a/2)+tan(b/2)=1-tan(a/2)tan(b/2)
tan(a/2)+tan(b/2)/(1-tan(a/2)tan(b/2))=1
tan(a/2+b/2)=1
a/2+b/2=π/4(a,b是锐角)
a+b=π/2
tanatanb=1