y=3sin(k 5x pie 3).k>0,x取任意两数之间的数都有最大最小值
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sinx的周期是2pai,sin3x的周期是三分之二pai,sin5x的周期是五分之二pai取其最小公倍数,则y的周期是2pai.
sin(x+y)sin(x-y)=-1/2(cos(x+y+x-y)—cos(x+y-x+y))=-1/2(cos2x—cos2y)=-1/2(1-2(sinx)^2-1+2(siny)^2)=(si
你用积化和差公式一套,然后就能看出它的最小正周期来的.应该是1pi
y=sin(sinx)y‘=cos(sinx)*(sinx)'=cos(sinx)*cosx
直接画不行吗t=0:5:600;y=sin(314*t)+sin(3*314*(t-0.065))+sin(5*314*(t-0.09))+sin(11*314*(t-0.14));plot(x,y)
y=sin^3x是复合函数可以设t=sinxt'=cosxy=t^3y'=3t^2*t'y'=3sin^2x*cosx
y=sin^3x+sinx^3y'=3sin²xcosx+cosx³*3x²=3sin²xcosx+3x²cosx³
∵(π3+4x)+(π6-4x)=π2,∴cos(4x-π6)=cos(π6-4x)=sin(π3+4x),∴原式就是y=2sin(4x+π3),这个函数的最小正周期为2π4,即T=π2.当-π2+2
y=sin(π3+x)cos(π3-x)=(32cosx+12sinx)(12cosx+32sinx)=34+sinxcosx=34+12sin2x当函数y=sin(π3+x)cos(π3-x)取得最
y'=(cos²x)'-(sin3^x)'=2cosx·(cosx)'-cos3^x·(3^x)'=2cosx·(-sinx)-cos3^x·(3^x·ln3)=-sin2x-ln3·cos
因为是1/3由1/3->1是缩短根据左加右减的原则选A
sin^2x+cos^2y=1/2∴sin^2x=1/2-cos^2y3sin^2x+sin^2y=3(1/2-cos^2y)+sin^2y=1.5-3cos^2y)+sin^2y又有sin^2y+c
y=sin(x+π/3)sin(x+π/2)=sin(x+π/3)cosx=(sinxcosπ/3+cosxsinπ/3)cosx=1/2sinxcosx+√3/2cos^2(x)[cos^2(x)指
Sinx-siny=2/3cosx-cosy=1/2分别平方得(Sinx-siny)^2=(2/3)^2(cosx-cosy)^2=(1/2)^2展开相加得-2cos(x-y)+2=4/9+1/4-2
[3/2,13/4]
由题意x∈[0,π2],得x+π3∈[π3,5π6],∴sin(x+π3)∈[12,1]∴函数y=sin(x+π3)在区间[0,π2]的最小值为12故答案为12
y=3sin(x+20°)+5sin(x+80°)=3sin(x+20°)+5sin(x+20°+60°)=3sin(x+20°)+5*[sin(x+20°)*cos60°+cos(x+20°)*si
y=sin²x+2sinxcosx+3cos²xy=(sin²x+cos²x)+2sinxcosx+(2cos²x-1)+1=1+sin2x+cos2
y=3^[sin(1/x)]y'=3^[sin(1/x)]ln3*cos(1/x)*(-1/x^2)=-ln3*3^[sin(1/x)]*cos(1/x)/x^2