Sin^2 45°+cos^2 45°=?
Sin^2 45°+cos^2 45°=?
2cos 30°-2sin 60°·cos 45°=?
sin(45/2)/cos(45/2)=?
√(cos 60°-1)²+2√cot 45°-sin 60°+|sin 30°-1|=?
求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos
-cos(α-45°)=sin(α+45°)对吗?
[sin(45°+θ)]/[cos(45°-θ)]-[cos(θ+60°)]/[sin(θ+30°)]=?
sinΘ-2cosΘ=0,Θ属于(0.,90°),求sinΘ、cosΘ的值.
(cos 45°-sin 30°)/(cos 45°+sin 30°)
已知sin+cos除以sin-cos=2则sin cos的值为
求值:sin^2 120+cos 180+tan 45—cos^2(-330)+sin(-210)
sin(aX+b)+cos(aX+b)=根号2乘sin(aX+b+45度)为什么