已知sin(a π 3) sina=-4根号3 5,则sin(-a 5π 6)
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sin(a+π/3)+sina=(-4/5)*根号3展开左边,即√3sin(a+π/6)=(-4/5)*根号3∴sin(a+π/6)=-4/5∵-π/2再问:麻烦下左边的式子怎么拆开请帮下。。怎么得到
3(sinA)^2+2(sinB)^2=5sinA(sinA)^2+(sinB)^2=5sinA/2-(sinA)^2/25sinA/2-(sinA)^2/2=-(1/2)(sinA-5/2)^2+2
sinacosπ/3+cosasinπ/3+sina=-4√3/5sina*3/2+cosa*√3/2=-4√3/5√3(sina*√3/2+cpsa*1/2)=-4√3/5sinasinπ/3+cp
sin(a+π/3)+sina=sinacos(π/3)+sin(π/3)cosa+sina=-4√3/5化简得到√3sina+cosa=-8/5再利用sina^2+cosa^2=1带入解得cosa再
因为sin(2π-a)=sina所以,sin(3π-a)=sin(π-a)=sina不懂的欢迎追问,再问:Thanks,那什么时候sina才可以换成cosa呢,再答:sin(π/2-a)=cosasi
(3sina+cosa)/(3cosa-sina)=23sina+cosa=6cosa-2sina5sina-5cosa=0tana=12-3sin(a-3π)sin(3π/2-a)-cos^2(-a
去括号啊sinπ+sina=1/3,sina=1/3-sinπ
sin(π/2+2a)=cos2a=1-2sin²a=7/25
1.(sina+cosa)/(2sina-cosa)=(tana+1)/(2tana-1)=(3+1)/(6-1)=4/52.tana=sina/cosa=3sina=3cosasin²a+
(1)展开,得sinAcosπ/4+cosAsinπ/4+sinAcosπ/4-cosAsinπ/4=2sinAcosπ/4=√2×sinA=√2/3所以,sinA=1/3.(2)原式=[sinAco
sina=sin[(a-π/3)+π/3]=sin(a-π/3)cosπ/3+cos(a-π/3)sinπ/3=1/2*sin(a-π/3)+根号3/2cos(a-π/3)=1/6+根号3/2cos(
sina=-2cosasin(a-3π)+cos(π-a)/sin(-a)-cos(π+a)=(-sina-cosa)/(-sina+cosa)=(2cosa-cosa)/(2cosa+cosa)=1
(tanπ/4+tana)/(1-tanπ/4tana)=3tanπ/4=1所以tana=1/2sina/cosa=tana=1/2cosa=2sina带入恒等式sin²a+cos²
/>∵sina=15/17,a∈(π/2,π)∴cosa=-√(1-sin²a)=-8/17∴sin(π/3+a)=sin(π/3)cosa+cos(π/3)sina=(1/2)√3×(-8
∵sina=15/17,a∈(π/2,π)∴cosa=-√(1-sin²a)=-8/17∴sin(π/3+a)=sin(π/3)cosa+cos(π/3)sina=(1/2)√3×(-8/1
sin(π-a)-cos(π+a)=√2/3sina+cosa=√2/3两边平方得1+2sinacosa=2/9sinacosa=-7/18(1)(sina-cosa)²=1-2sinaco
sin(a+π/4)cos(a+π/4)=(1/2)*sin[2(a+π/4)]=(1/2)*sin(2a+π/2)=(1/2)*cos(2a)=(1/2)*[1-2*(sina)^2]=(1/2)*
手机提问的朋友在客户端右上角评价点【评价】,然后就可以选择【满意,问题已经完美解决】了再问:原式最后的结果怎么算的再答:如图无图请追问如果你认可我的回答,请点击“采纳回答”,祝学习进步!手机提问的朋友
sin(π-a)cos(2π-a)sin(-a+1.5π)/(tan(-a-π)sin(-π-a))=sin(a)cos(a)sin(-a-0.5π)/(tan(-a)sin(π-a-2π))=(-1