sin(−π3)+2sin4π3+3sin2π3等于( )
化简sin^3α×sin3α+cos^3α×cos3α+1/2sin2α×sin4α
已知β是第三象限角,且sin4β+cos4β=5/9,那么sin2β等于多少?答案是(2√2)/3
证明:sinπ/9[(sinπ/9)+sin(3π/9)]=sin2(2π/9)
化简:(sinα-cosα)^2+sin4α/2cos2α 化简:sin^2x+sin^2(x+2π/3)+sin^2(
sin2/3π=sin(π-π/3)吗?
已知sin2α=1/3 (α∈(0,π/2) ) ,则sinα+cosα等于
若sin(π/4+α)=sinθ+cosθ,2sin^2β=sin2θ,求证:sin2θ+2cos2β=3
sin(α+π/4)=1/3,则sin2α
sin2(π3
已知α∈(π/2,π),且sinα=3/5,则sin^2α/2+(sin4αcos2α)/(1+cos4α)的值为多
若cos4分之πcosθ-sin4分之3πsinθ=0,θ的绝对值
Θ∈(π/2,3π/4) sin2Θ∈a sinΘ+cosΘ