证明tan a/2=sin a/(1+cos a)
证明tan a/2=sin a/(1+cos a)
证明恒等式tan a*sin a/tan a-sin a=1+cos a/sin a
证明:cos^4 a-sin^4 a=cos^2 a(1-tan a)(1+ tan a)
tan a/2=(1-cos a)/sin a=sin a/(1+cos a)如何证明?
为什么 tan a +1/tan a=sin^2 a +cos^2 a/(sina cos a)
证明1-COS^2α/(SINα-COSα)-SINα+COSα/(TAN^2a-1)=SINa+COSa
tan a/2=sin/1+cos a=1-cos a/sin a
求证:tan a/2=(1-cos)/sin a=sin a/(cos a+1)
证明:(1+tan a+cot a)/(1+tan^2 a+tan a)-cot a/(1+ tan^2 a)=sin
证明Cos^A-Sin^A=1-2Sin^A=2Cos^A-1=cos^a-sin^a
证明:(tan a-cot a)/(sec a+csc a)=sin a-cos a
(1) 证明1+sec a+tan a/1+sec a -tan a=1+sin a /cosa (2)sinx+cos