2sin的平方α-3根号3sinα 3=0中锐角α的度数
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f(x)=2sin平方x-根号3sinxcosx+cos平方x=1-cos2x-√3/2sin2x+1/2(cos2x+1)=1-cos2x-√3/2sin2x+1/2cos2x+1/2=3/2-1/
函数f(x)=2sin^2(x+π/4)-√3cos2x-1=-cos(2x+π/2)-√3cos2x=sin2x-√3cos2x=2sin(2x-π/3)1.当x属于R时,函数f(x)的最小正周期T
△ABC,角A,B,C的范围均在(0,派)sin(2π+A)=-根号2sin(π+B)推出:sinA=根号2sinB(1)根号3cosA=-根号2cos(π-B)推出:根号3cosA=根号2cosB推
1、∵sin2α=2sinαcosα,(sinα+cosα)²=1/4又∵(sinα+cosα)²=sinα²+cosα²+2sinαcosα又∵sinα&su
解(1):∵tanα=-2∴cosα≠0sin²α+2sinαcosα-3cos²α=(sin²α+2sinαcosα-3cos²α)/(sin²α+
f(x)=√3/2sin2x-1/2(1-cos2x)+1/2=√3/2sin2x-1/2+1/2cos2x+1/2=√3/2sin2x+1/2cos2x=sin(2x+π/3)
由sin²x+cos²x=1得出的再问:���Ƕ��˸�2��ϵ��再答:��Ϊ֮ǰ��3cos²x再答:sin²x+3cos²x=sin²
y=sinx^2+根3sinxcosx+2cosx^2=-1/2(1-2sinx^2)+1/2根3*2sinxcosx+2cosx^2-1+3/2=-1/2cos2x+二分之根3倍sin2x+cos2
f(x)=2√3sin²x-sin(2x-π/3)=√3-√3cos2x-1/2sin2x+√3/2cos2x=√3-(1/2sin2x+√3/2cos2x)=√3-sin(2x+π/3)T
(2cos平方θ/2-sinθ-1))/根号2sin(θ+π/4)=(cosθ-sinθ)/根号2sin(θ+π/4)=根号2cos(θ+π/4)/根号2sin(θ+π/4)=1/tan(θ+π/4)
根号下cos的平方α-2cosα×sinα+sin的平方α=根号下(cosα-sinα)²=(cosα-sinα)的绝对值.
利用图像法即可先考虑定义域x≤2因为-2≤2sin(3x)≤2所以只需考虑√(2-x)≤2所以-2≤x≤2画出图像,y=√2-x,y=3sin(3x)两个图像有4个交点,所以方程有四个实根
(sinC)^2=(sinA)^2+(sinB)^2,由正弦定理,c^2=a^2+b^2,(1)C=90°.(2)(1/2)ab=√3,a^2+b^2=16,∴(a+b)^2=16+4√3,∴a+b=
在三角形ABC中,由正弦定理可得a/sinA=b/sinB=c/sinC结合题设可得a²+b²=2c²[[1]]可设C(x,√3)∴a²=|BC|²=
sin²B-sin²C-sin²A=√3sinAsinC在⊿ABC中,由正弦定理知,a/sinA=b/sinB=c/sinC=2R.===>sinA=a/2r.sinB=
2sin的平方α—3根号3sinα+3=0(2sina-根号3)(sina-根号3)=02sina-根号3=0或sina-根号3=0sina=根号3/2或sina=根号3因为|sina|
=2x3/4-1+√3=1/2+√3
2sin(A-15度)=根号3sin(A-15°)=√3/2A-15°=60°∴A=45°sin^2a+sin^230度=1sin^2a=1-1/4=3/4sina=√3/2或-√3/2(舍去)∴x=
根号2倍的sin(a+pei/4)=√2(sinacosπ/4+cosasinπ/4)=√2(√2/2sina+√2/2cosa)=sina+cosa=3sinacosa=2sina(2sin^2a+