cp987
幼苗
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x^2 / (4/cosθ) + y^2 / (4/cotθ) = 1
a^2 = 4/cosθ
b^2 = -4/cotθ
c^2 = a^2 + b^2 = 4( 1/cos^2θ + 1/cot^2 θ) = 8
1/cos^2 θ + 1/cot^2 θ = 2 = (1+sin^2θ) / cos^2θ
cos^2 θ = 2/3
sin^2θ = 1/3
tan^2 θ = 1/2
tanθ = -根号(2)/2
1年前
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