sin6度2025"

1-(sin^6a+cos^6a)根据a^3+b^3=(a+b)(a^2-a*b+b^2)=1-[(sin^2a+cos^2a)*(sin^4a-sin^2acos^2a+cos^4a)]根据sin^

原式=sin(π/6)+cos(π/3)-tan(π/4)=1/2+1/2-1=0

sinA=2sin(A/2)cos(A/2)；1-cosA=2sin²(A/2)；1+cosA=2cos²(A/2)又：tan（A/2）=√5,故：sin(A/2)cos(A/2)

原式=[cos15sin9+sin(15-9)]/[sin15sin9-cos(15-9)]=(cos15sin9+sin15cos9-cos15sin9)/(sin15sin9-cos15cos9-

（-1）2013次方减（2分之一）负3次方+（cos45°）的0次方+绝对值3根号3减8sin6=-1-8+1+l3√3-4√3l=-8+√3如果本题有什么不明白可以追问,

Sin(-6分派)＋Cos3分4派+Tan(-4分5派)=-1/2-1/2-tan(5π/4)=-1-1=-2

y=sin^6x+cos^6=(sin^2x+cos^2x)(sin^4x-sin^2xcos^2x+cos^4x)=sin^4x-sin^2xcos^2x+cos^4x=sin^4x+2sin^2x

arccos(cos5π/4)=5π/4arctan(tan4π/3)=4π/3arcsin(sin6)=6

原式=2sin36cos36cos72/2sin36=sin144/4sin36=1/4cos20*cos40*cos60*cos80=2sin20cos20cos40cos80/4sin20=sin

原式=sin6cos24cos12cos48=2sin6cos6cos12cos24cos48/2cos6=sin12cos12cos24cos48/2cos6=sin24cos24cos48/4co

=sin(4π+5π/6)+cos(π/3-10π)+tan(3π/4-7π)=sin5π/6+cosπ/3+tan3π/4=1/2+1/2-1=0

方法：乘以一个cos6°,再除以一个cos6°sin6°sin42°sin66°sin78°=sin6°cos48°cos24°cos12°=(cos6°sin6°)cos48°cos24°cos12

由cos平方a+cosa-1=0cosa=1-cos^a=sin^2a即sin^2a=cosa代入sin平方a+sin6次方a+sin8次方a=cosa+cos^3a+cos^4a将cos^2a=1-

(sin6+cos15*sin9)/(cos6-sin15*sin9)=[sin(15-9)+cos15*sin9]/[cos(15-9)-sin15sin9]=(sin15cos9-cos15sin

等于3/2

原式=[cos15sin9+sin(15-9)]/[sin15sin9-cos(15-9)]=(cos15sin9+sin15cos9-cos15sin9)/(sin15sin9-cos15cos9-

sin6°cos24°sin78°cos48°=cos6°sin6°cos24°sin78°cos48°/cos6°=sin12°cos12°cos24°cos48°/2cos6°=sin24°cos

sin(25π/6)+cos(25π/3)+tan(-25π/4)=sin(25π/6-4π)+cos(25π/3-8π)+tan(-25π/4+7π)=sin(π/6)+cos(π/3)+tan(3

sin6°sin42°sin66°sin78°=sin6°cos12°cos24°cos48°=8cos6°sin6°cos12°cos24°cos48°/8cos6°=4sin12°cos12°co

sin9+sin6cos15=sin(15-6)+sin6cos15=sin15cos6-sin6cos15+sin6cos15=sin15cos6cos9-sin6sin15=cos(15-6)-s