(cos a)^4+(sin a)^2*(sin a)^2+(sin a)^2=?
(cos a)^4+(sin a)^2*(sin a)^2+(sin a)^2=?
证明Cos^A-Sin^A=1-2Sin^A=2Cos^A-1=cos^a-sin^a
(1-sin^6a-cos^6a)/(sin^2a-sin^4a)
若sin^4a/sin^2b+cos^4a/cos^2b=1,证明sin^4b/sin^2a+cos^4b/cos^2a
已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 2A+
化简Sin A + Sin 2A / 1+cos A +
化简:sin(-a)cos(2π+a)sin(-a-π)
已知tan a=2,求sin a+cos a /cos a -sin a 的值
已知 sin a,sin 2x ,cos a 成等差数列,sin a ,sin x ,cos a 成等比数列,求cos
化简[cos(a-π)/sin(π-a)]sin(a-π/2)cos(π/2+a)=
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)