Question

设θ为三角形内最小内角,acos^2(θ/2)+sin^2(θ/2)-cos^2(θ/2)-asin^2(θ/2)=a+

Answer 1

acos^2(θ/2)+sin^2(θ/2)-cos^2(θ/2)-asin^2(θ/2)=a+1

化简后,有

acosθ-cosθ=a+1,

cosθ=(a+1)/(a-1),

θ为三角形内最小内角,则有

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