sin+x+π+等于多少

宿于申2888函数y=sin(x+π/6)+cosx的最大值是多少? -
胥凭研15151344029 ______[答案] y=sin(x+π/6)+cosx =sinxcosπ/6+cosxsinπ/6+cosx =√3/2sinx+1/2cosx+cosx =√3/2sinx+3/2cosx =√3(1/2sinx+√3/2cosx) =√3(sinxcosπ/3+cosxsinπ/3) =√3sin(x+π/3)

宿于申2888f(x)=根号3sin(x+π/2)+sinx等于多少,要过程. -
胥凭研15151344029 ______ f(x)=√3sin(x+π/2)+sinx =√3cosx+sinx =2(√3/2cosx+1/2sinx) =2(sinπ/3cosx+cosπ/3sinx) =2sin(x+π/3)

宿于申2888已知sin(x+π/4)= - 3/5则sin2x的值是多少
胥凭研15151344029 ______ cos[2(x+π/4)]=cos(2x+π/2)=-sin2x 又cos[2(x+π/4)]=1-2(sin(x+π/4))^2=1-2*(-3/5)^2=7/25 所以,sin2x=-7/25

宿于申2888sin( x + 六分之π)=三分之二 ,则sin (六分之19π + x) +[sin(三分之 π - x)的平方]=?sin( x + 六分之π)=三分之二 ,则sin (六分之19π + x) +[sin(三分之 π ... -
胥凭研15151344029 ______[答案] sin (六分之19π + x) +[sin(三分之 π - x)的平方]= =sin(3π+π/6+x)+[cos(π/6+x)]^2 =-sin(π/6+x)+1-[sin(π/6+x)]^2 =-2/3+1-4/9 =-1/9

宿于申2888sin(x+π/6) + sin(x - π/6) 等于多少 ,?怎么算??/ -
胥凭研15151344029 ______ 公式:sinαcosβ = [sin(α+β)+sin(α-β)]/2 sin(x+π/6) + sin(x-π/6) =2sinXcosπ/6=√3 sinx

宿于申2888Sin(x+派/4)换成Cos等于什么啊RT -
胥凭研15151344029 ______[答案] sin(x+π/4)=sin(π/2-π/4+x) =sin[π/2-(π/4-x)] =cos(π/4-x)

宿于申2888cos(x - π/4)=根号2/10,则sin(x+π/4)=?? -
胥凭研15151344029 ______ π/2<x<3π/4 π/4<x-π/4<π/2 因为cos(x-π/4)=√2/10 所以sin(x-π/4)=√98/10 那么tan(x-π/4)=√(98/2)=7 (tanx-1)/(1+tanx)=7 解得 tanx=-4/3 sin2x=2tanx/(1+tan²x)=-24/25 cos2x=(1-tan²x)/(1+tan²x)=-7/25 sin(2x+π/3)=sin2xcosπ/3+cos2xsinπ/3=(-24/25)*(1/2)+(-7/25)*(√3/2)=-(24+7√3)/50 过程

宿于申2888函数y=sin(x+π/8)cos(x - π/24)
胥凭研15151344029 ______ y=sin(x+π/8)cos(x-π/24) =(1/2)*{sin[(x+π/8)+(x-π/24)]+sin[(x+π/8)-(x-π/24)]} =(1/2)*[sin(2x+π/12)+sin(π/6)] =(1/2)*sin(2x+π/12)+1/2

宿于申2888f(x)=4cosxsin(x+π|6) - 1的最小周期是多少?怎么看的. -
胥凭研15151344029 ______[答案] f(x)=4cosxsin(x+π/6)-1 =4cosx[[(√3/2)sinx+(1/2)cosx]-1 =2√3sinxcosx+2(cosx)^2-1 =√3sin2x+cos2x =2sin(2x+π/6) f(x)的最小正周期是T=2π/2=π.

宿于申2888√3sinx+cosx=2(√3/2sinx+cosx/2)为什么等于2sin(x+π/6) -
胥凭研15151344029 ______ √3/2sinx+cosx/2=cosπ/6sinx+sinπ/6cosx=sin(x+π/6) 要用到这个公式:sinxcosy+cosxsiny=sin(x+y)