cos a =0.75 求tg a

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cosa=0.75求tgacosa=0.75求tgacosa=0.75求tgacosa=0.75求tgasina=(1-(cosa)^2)^0.5=(1-(0.75)^2)^0.5=0.66144tg

cos a =0.75 求tg a
cos a =0.75 求tg a

cos a =0.75 求tg a
cos a =0.75 求tg a
sin a=(1-(cos a)^2)^0.5=(1-(0.75)^2)^0.5=0.66144
tg a=sin a/cos a=0.66144/0.75=0.88192

∵tga=1,∴a=kπ+π/4,k∈z.∴2a=2kπ+π/2
∴sin(2a+b)=sin2acosb+sinbcos2a=cosb=3sinb
∴tanb=1/3
∴tg(a+b)=(tga+tgb)/(1-tgatgb)=(1+1/3)/(1-1/3)=2