已知sinx=2分之根号2且x属于-2分之π,二分之π,求x
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cosx=1/7cos(x-y)=13/14siny=sin(x-(x-y))=sinxcos(x-y)-cosxsin(x-y)=4√3/7*13/14-1/7*3√3/14=√3/2所以y=π/3
解析sinx+cosx=√2/2(sinx+cosx)2=1/2(sinx+cosx)2=1+sin2x=1/2sin2x=-1/2(sinx-cosx)2=1-sin2x=3/2sinx-cosx=
这么简单的都不会?数学课没听讲吧?第一步,化简所求式子:1/(sinx)^2+1/(cosx)^2=((sinx)^2+(cosx)^2)/((sinx)^2*(cosx)^2)=1/((sinx)^
已知:函数f(x)=2sinxcosx+2√3cos²x-√3求:(1)单调增区间和最小正周期;(2)当x∈[-π/4,π/4]时求最值.f(x)=2sinxcosx+2√3cos²
F(x)=m.n=2根号3sinxcosx+cos^2x-sin^2x=根号3sin2x+cos2x=2sin(2x+π/6)
cos(x+y)=cosxcosy-sinxsiny=2分之根号二所以X+Y=45度再问:cosxcosy-sinxsiny=2分之根号二能写下他的过程吗?因为不知道COSX和COSY是多少、、再答:
1f(x)=2sinX平方+2跟3sinxcosx+a把x=π/3代入f(x),sinπ/3=跟3/2cosπ/3=1/2f(x)=2*3/4+3/2+a=4a=1f(x)=跟3sin2x-cos2x
sinx-cosx=根号5/5平方sin^2x-2sinxcosx+cos^2x=1/51-2sinxcosx=1/52sinxcosx=1-1/5=4/5sinxcosx=2/5
解:由题意可得:(sinx+cosx)^2=1+sin2x=1-√3/2所以sin2x=-√3/2,所以2x=π+π/3或2x=2π-π/3因为0
f(x)=向量m.向量nf(x)=2sin^2x+2√3sinxcosx.=1-cos2x+√3sin2x.∴f(x)=2sin(2x-π/6)+1.(1)函数f(x)的最小正周期T:T=2π/2,∴
(1)f(x)=msinxcosx-2√3(sinx)^2+√3=(m/2)sin2x+√3cos2x,x=π/6是函数y=f(x)的零点,∴(m/2+1)√3/2=0,m=-2.∴f(x)=-sin
向量m=(2cosx,√3cosx-sinx),n=(sin(x+π/6),sinx),且满足f(x)=m·nf(x)=m·n=2√3sinxcosx+cos²x-sin²x=√3
[sinx+cos(π+x)]/[sinx+sin(π/2-x)]=(sinx-cosx)/(sinx+cosx)=(tanx-1)/(tanx+1)=1-[2/(tanx+1)]sinx=√3/3∴
f(x)=√2(sinx-cosx)=2*【sinxcos(-π/4)+cosxsin(-π/4)】=2sin(x-π/4)1)、f(x)的最小正周期为T=2π值域为【-2,2】2)、图像过点(α,6
已知tanx=根号2则[2cos2(x/2)-sinx-1]/(sinx+cosx)=(cosx-sinx)/(sinx+cosx)=(1-tanx)/(tanx+1)=(1-√2)/(1+√2)=(
cos(x-90)=cos(90-x)=sinx=√2/10∴sinx=√2/10再问:cos(X-45)=根号2/10,X属于90到135度,求sinx和sin(2x+60)再答:=cos(x-45
由sinx<2分之根号2可以想一想x=4分之π或4分之3π时sinx=2分之根号2根据画图(应该学过吧)可得—4分之5π+2kπ
X^2-3X+1=0x+1/x=3x+2+1/x=5(根号x+根号x分之1)平方=5则根号x+根号x分之1=根号5再问:还有若根号(2012-m)²+根号m-2013=m,求代数式m-201
1、f(x)=sinx(sinx+√3cosx)=sin²x+√3sinxcosx=(1-cos2x)/2+(√3/2)sin2x=(√3/2)sin2x-(1/2)cos2x+1/2=si
1f(x)=2sinX平方+2跟3sinxcosx+a把x=π/3代入f(x),sinπ/3=跟3/2cosπ/3=1/2f(x)=2*3/4+3/2+a=4a=1f(x)=跟3sin2x-cos2x