cosa=x/r
sina=y/r
x^2+y^2=r^2
x/r+2y/r=-√5
x+2y=-√5r
x^2+4xy+4y^2=5r^2=5x^2+5y^2
4x^2-4xy-y^2=0
(2x-Y)^2=0
2x=y
x/y=1/2
tana=x/y=1/2
(1)若 cosa+2sina=-√5,则 tana=
(1)若 cosa+2sina=-√5,则 tana=
数学人气:893 ℃时间:2020-06-22 11:09:06
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