已知sin[75 x]=三分之一
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(1)f(x)=√3(1-cos2x)-1/2sin2x+√3/2cos2x=√3-1/2sin2x-√3/2cos2x=√3-sin(2x+π/3)∴最小正周期T=2π/2=π单调增区间:π/2+2
周期是派最大值是2X=1/3派+K派(-1/6派+K派,1/3派+K派)
cos(45°+α)=cos(α-45°+90°)=-sin(α-45°)=-1/3如果不懂,祝学习愉快!
cosa-cosβ=1/2,sina-sinβ=-1/3;----------(cosa-cosβ)^2-(sina-sinβ)^2=cosacosa+cosβcosβ-2cosacosβ-(sina
f(x)=2sin(π-x)sin(π/2-x)=2sinxcosx=sin2x1)最小正周期=2π/2=π2)在区间[-派/6,派/2]上x=π/4时,有最大值=sinπ/2=1x=-π/6时,有最
f(x)=2sinx*sin(π/2+x)-2sin^2x+1=2sinxcosx+cos2x=sin2x+cos2x=√2sin(2x+π/4)因为f(x0/2)=根2/3所以sin(x0+π/4)
cos(75°+a)=-cos(180°-75°-a)=-cos(105°-a)=1/3cos(75°+a)=sin(90°-75°-a)=sin(15°-a)=1/3sin(a-15°)=-1/3c
sin(x+π/6)=1/3sin(5π/6-x)=sin[π-(x+π/6)]=1/3sin^2(π/3-x)=sin^2[π/2-(x+π/6)]=cos^2(x+π/6)=1-sin^2(x+π
f(x)=2√3sin²x-sin(2x-π/3)=√3-√3cos2x-1/2sin2x+√3/2cos2x=√3-(1/2sin2x+√3/2cos2x)=√3-sin(2x+π/3)T
(根号2+根号6)÷4再问:如何做的??????????谢谢
fx=2cosx(0.5sinx+根号3/2cosx)-根号3sin*2x+sinxcosx=2sinxcosx+根号3(cos*2x-sin*2x)=sin2x+根号3cos2x=2sin(2x+派
∵tana=-1/3∴(5cosa-sina)/(sina+2cosa)=(5cosa-sina)÷cosa/(sina+2cosa)÷cosa=(5-tana)/(tana+2)=(5-(-1/3)
已知cosα等于-三分之一0sin^2a+cos^2a=1所以sina=2根号2/3tana=sina/cosa=-2根号2(1)a属于第三象限sina
由和差化积公式分子=2sin[(x^3+x^2)/2]cos[(x^3+x^2-2x)/2]x→0,则(x^3+x^2)/2→0,sin则(x^3+x^2)/2和(x^3+x^2)/2是等价无穷小而c
(1)F(X)=√3sin2x+2sin²x=√3sin2x+1-cos2x=2(√3/2sin2x-1/2cos2x)+1=2sin(2x-π/6)+1F(x)的最小正周期T=2π/2=π
(Ⅰ)f(x)=sinx•cosx+12cos2x+12=12sin2x+12cos2x+12=22sin(2x+π4)+12∴函数f(x)的最小正周期T=2π2=π(Ⅱ)当x∈[−π8,3π8]时,
f(x)=(√3/2)sin2x-(1/2)[(cosx)^2-(sinx)^2]-1=(√3/2)sin2x-(1/2)cos2x-1=sin(2x-π/6)-1f(x)的最大值是0,最小值是-2,
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sinx=2cosx,sin^2x=4cos^2xsin^2x=4-4sin^2x,sin^2x=4/5(cosx+sinx)/(cosx-sinx)+sin^2x=(1+tanx)/(1-tanx)
sinα+cosβ=1/3平方,sin²α+cos²β+2sinαcosβ=1/9(1)sinβ-cosα=1/2平方,sin²β+cos²α-2sinβcos