cos5/6π等于多少
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1,cos5π/12·sinπ/12=cos(π/4+π/6)*sin(π/4-π/6)=(√6-√2)/4*(√6+√2)/4=1/42.√[cos4-sin^2(2)+2]=√[cos^2(2)-
不对,左边等于-1/12,右边等于0
构造直角三角形ABCC=π/2,B=5π/12,A=π/12sinπ/12=sinA=对边/斜边=BC/ABcos5π/12=cosB=邻边/斜边=BC/AB故cos5π/12等于sinπ/12再问:
sin25π/6+cos5π/3+tan(-25π/4)+sin(-7π/3)×cos(-13π/6)-sin(-5π/6)×cos(-5π/3)=sin(4π+π/6)+cos(2π-π/3)+ta
cos5π/7=cos(π-2π/7)=-cos2π/7tan5π/7=tan(π-2π/7)=-tan2π/7偶函数,f(-x)=f(x)所以f(cos5π/7)=f(cos2π/7)f(tan5π
cos5π/8*cosπ/8=-cos(π-5π/8)*cosπ/8=-cos3π/8*cosπ/8=-cos(π/2-π/8)*cosπ/8=-sin(π/8)*cosπ/8=-sin(π/4)/2
cos5/12πcosπ/12+cosπ/12sinπ/6=cosπ/12(cos5/12π+sinπ/6)=cosπ/12(cos(π/2-π/12)+sinπ/6)=cosπ/12(sin(π/1
cos²5π/12+cos²π/12+cosπ/12*cos5π/12由于cos5π/12=sin(π/2-5π/12)=sinπ/12原式=sin²π/12+cos
cos^2(π/4+π/6)+cos^2(π/4-π/6)+1/2[cos(5π/12+π/12)+cos(5π/12-π/12)]=cos^2(π/4+π/6)+cos^2(π/4-π/6)+1/2
【注:sin2x=2sinxcosx.sin(π-x)=sinx】原式=(1/2)×2sin(5π/12)cos(5π/12)=(1/2)sin(5π/6)=(1/2)sin[π-(π/6)]=(1/
cosπ/5×cos2π/5=(2sinπ/5×cosπ/5×cos2π/5)/(2sinπ/5)=(sin2π/5×cos2π/5)/(2sinπ/5)=(2sin2π/5×cos2π/5)/2×(
cos5分之πcos10分3π-sin5分之πsin10分之3π=cos(5分之π+10分3π)=cos2分之π=0
①-√2/2②1/2③同①④1⑤√3/3⑥同①
点P横坐标为正,纵坐标为负,在第四象限!P(1/2,-根3/2)α终边与-60度终边相同.
cos(6π-α)=√3/3-->cosα=√3/3然后就降幂化简原式,但你的题目好像没写全
因为sin(5派/6)=1/2,cos(5派/6)=--(根号3)/2,所以角a终边上的这一点在第四象限,因为这一点的坐标为(1/2,--(根号3)/2),所以这一点到原点的距离为1,所以cosa=(
应该限定a是正角.因为一个角终边与单位圆的焦点坐标为(cosA,sinA)所以知道cosa=sin5π/6,sina=cos5π/6如果a是正的话就最小值就是5π/3了再问:一个角终边与单位圆的焦点坐
多次用倍角公式···可以得到关系关于某个特殊角的多次方···具体自己找找公式···我毕业N久了··公式不记得了···
(cos5分之π+cos5分之2π+cos5分之3π+cos5分之4π)=(cos5分之π+cos5分之4π++cos5分之2π+cos5分之3π)=2cos[(5分之π+5分之4π)/2]*cos[
只能求正负再问:咋求。。这节课我没听,。。再答:1好像等于37°多吧。忘了。高一学的。然后看图像。再问:哦哦