化简 1+sina+cosa+2sinacosa/1+sina+cosa
证明1+sina+cosa+2sinacosa/1+sina+cosa=sina+cosa,
已知sina+cosa=1/5求sinacosa,sina-cosa
已知3sina=-cosa,求值 (1)sina-3cosa/sina+3cosa (2)1+sinacosa
已知sina+cosa=p,求(1)sinacosa (2)sina平方-cosa平方 (3)sina三次方加减cosa
已知4sinacosa-5sina-5cosa-1=0求sina.sina.sina+cosa.cosa.cosa的值.
sina+cosa/sina-cosa=2 求sin^2a-2sinacosa+1
已知2sina=-cosa,则1+2sinacosa/(sina-cosa)=?
已知sina>cosa,则根号(1-2sinacosa)/sina-cosa=
求证:1+sina+cosa/1+sina-cosa+1-cosa+sina/1+cosa+sina=2/sina
求证:sinA+cosA=√1+2sinAcosA
sinacosa=1/2,tana+cosa/sina的值
已知tana=3, (1)sina-cosa/sina+cosa (2)(sina)^2-3sinacosa+1 急!