sinθ/2=√(x-1/2x) ,tanθ=?
问题描述：
sinθ/2=√(x-1/2x) ,tanθ=?
答
tanθ=sinθ/conθ=(2sinθ/2·cosθ/2)/[1-(sinθ/2)^2]
=正负2√(x-1/2x)√(1-x+1/2x)/(1-x+1/2x)
=正负2√(x-1/2x)/√(1-x+1/2x)^3
答
sin^2(a/2)=(x-1)/(2x)
1-2sin^2(a/2)=(1-x)/x+1=1/x=cosa
cos^2a=1/x^2
sin^2a=1-cos^2a=(x^2-1)/x^2
tan^2a=(x^2-1)
tana=√(x^2-1)
回答完毕!