cos^2 22.5 °- sin^2 22.5°
2sin@+cos@等于?
sin^2 22.5度-cos^2 22.5度=
Sin^2 45°+cos^2 45°=?
(cos^2)15°+(sin^2)15°等于多少
sin^2 80°等于 cos^2 10°?
化简:根号1+2sin(40°)cos(40°)
(cos^2)15°-(sin^2)15等于多少
化简cos^2(-α)-[tan(360°+α)/sin(-α)]
sinΘ-2cosΘ=0,Θ属于(0.,90°),求sinΘ、cosΘ的值.
求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos
求2sin(-1110°)-sin960°+根号2cos(-225°)-cos(-210°)
(cos^2 10°-cos^2 80°)+sin^2 20°