已知cos(x-π)=10分之根号二
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有2个值如图手机提问的朋友在客户端右上角评价点【采纳】即可
f(x)=sin2x+2sin(π/4-x)cos(π/4-x)=sin2x+cos2x=√2sin(2x+π/4)所以T=2π/2=πx属于[-π/12,π/2]得到2x+π/4属于[π/12,5π
因为sin(4分之π-x)等于13分之5,即sin(π/4-x)=5/13cos(x-π/4+π/2)=-sin(x-π/4)=sin(π/4-x)=5/13cos[2(x+π/4)]=-sin2x=
已知函数f(x)=cos(2x-π/3)+sin²x-cos²x=(cos2x)/2+(√3sin2x)/2-cos2x=-(cos2x)/2+(√3sin2x)/2=sin(2x
∵cos(x-π/6)=-√3/3∴cosx+cos(x-π/3)=cosx+cosxcosπ/3+sinxsinπ/3=cosx+(1/2)cosx+(√3/2)sinx=(3/2)cosx+(√3
f(x)=2sin^2x+cos(2x-π/3)-1=(2sin^2x-1)+cos(2x-π/3)=-cos2x+1/2*cos2x+√3/2*sin2x=√3/2*sin2x-1/2*cos2x=
tan(派/4+x)=(1+tanx)/(1-tanx)=(cosx+sinx)/(cosx-sinx)=3cosx+sinx=3cosx-3sinx2sinx=cosxtanx=1/2sin2x-2
cos(x-π/6)=-√3/3cosx+cos(x-π/3)=cos(x-π/6+π/6)+cos(x-π/6-π/6)=cos(x-π/6)cosπ/6-sin(x-π/6)sinπ/6+cos(
∵cos(π/4+x)=4/5,∴cosx-sinx=(4/5)√2两边平方得,cos²x+sin²x-2sinxcosx=32/25则,2sinxcosx=-7/25∴(cosx
f(x)=-cosx+cos(2分之π)cos(2分之π)=0,cosx属于[-1,1]f(x)最大值1,最小值-1(2)sin2x=1/32sinxcosx=1/31+2sinxcosx=4/3si
sin(x-4分之π)=-sin(π/4-x)=-sin[π/2-(π/4+x)]=-cos[(π/4)+x]=1/3所以:cos[(π/4)+x]=-1/3
f(x)=cos(2x-π/3)-(cos^2x-sin^2x)=cos(2x-π/3)-cos2x=2sin(2x-π/6)sinπ/6=sin(2x-π/6)因为y=sinx的单减区间为[π/2+
上面的等于5分支9,把括号拆开,整理等于1--sina,因为cosa等图-3/5,所以sina=-4/5下面的等于25分支17,把sin4a变成sin2a(1--cos2a),同理改cos4a,最后再
f(x)=cos(2x-π\3)+sin²x-cos²x=1/2cos2x+√3/2sin2x-cos2x=√3/2sin2x-1/2cos2x=-cos(2x+π\3)-1
f(x)=2cos²(x/2)-sinx+1=(1+cosx)-sinx+1=√2cos(x+π/4)+2(1)f(x)的周期为2π;由2kπ-π≤x+π/4≤2kπ得:2kπ-5π/4≤x
高中的知识诶,都快忘记了.三角函数有和差化积公式的用那个试一下
f(x)=cosx-cos(x+π/2)=cosx+sinxf(x)*f(x)=cosx*cosx+2sinxcosx+sinx*sinx=1+sin2x=3/4sin2x=-1/4
cos(x+4分之派)=5分之3cosxcosπ/4-sinxsinπ/4=3/5√2/2(cosx-sinx)=3/5得:cosx-sinx=3√2/5(cosx-sinx)^2=cos^2x-2s
f(x)=2sin(x-π/6)cosx+2cos²x=(2sinxcosπ/6-2cosxsinπ/6)cosx+2cos²x=√3sinxcosx-cos²x+2co
17π/12<x<7π/4,得5π/3<x+π/4<2πcos(x-π/4)=cos[(x+π/4)-π/2]=sin(x+π/4)=-√[1-sin²(x+π/4)]=-√[1-(3/5)