sin(2x+派/3)转换成cos(2x-派/6)
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根据诱导公式,sin(x-3π/2)cos(π-x)tan(π+x)=(cosx)(-cosx)(-tanx)=sinxcosx,∵sinx=3/5,∴cosx=±4/5,原式=±12/25.
f(x)=2根号3sin(x/2+派/4)cos(x/2+派/4)-sin(x+派).=(根号3)sin(x+π/2)-sin(x+π)=(根号3)cosx+sinx这一步用到诱导公式=2*((根号3
y=sin(2x-π/3)x∈[π/6,π/2]所以2x-π/3∈[0,2π/3]当2x-π/3=0即x=π/6时函数y有最小值为0当2x-π/3=π/2即5π/12时函数y有最大值为1所以值域为【0
原式=1/2sinx+根号3/2cosx+sinx-根号3cosx+根号3/2cosx-3/2sinx(先全部展开)=0(最后合并同类项得0)
2)f=1/2=sin(x)=kπ+π/6or2kπ+π/62n项和,可分奇数n项和偶数n项s奇=a1n+n(n-1)d/2=π*n/6+π*n(n-1)=π(n^2-5n/6)s偶=a1n+n(n-
sin(π-x)+sin(π+x)-cos(-x)+cos(2π-x)-tan(π+x)cot(π-x)=-sin(-x)-sin(x)-cos(x)+cos(-x)-[-tan(x)][-cot(-
f(x)=2根号3sin(x/2+派/4)cos(x/2+派/4)-sin(x+派).=√3sin(x+π/2)+sinx=sinx+√3cosx=2(1/2sinx+√3/2cosx)=2sin(x
sin(2派-x)tan(派+x)cot(-x-派)/tan(3派-x)cos(派-x)=-sinxtanxcot(-x)/tan(-x)(-cosx)=sinxtanxcotx/tanxcosx=s
sinx=-5/13x∈(П,3П/2)cosx=√1-(-5/13)^2=-12/13sin(x-П/4)=sinxcosП/4-cosxsinпП/4=√2/2(-5/13+12/13)=7√2/
f(x)=2√3sin(x-π/4)cos(x-π/4)-sin(2x-π)=√3sin(2x-π/2)-sin(2x-π)=-√3cos2x+sin2x=2((1/2)sin2x-√3/2cos2x
才5分==再问:提高了再答:1、π;5/2,1/22、-π/12再问:第二个问能详解一下么?谢再答:奇函数的话就意味着有一个对称中心(0,0),这时是最小的
原式=4sinx+4sin【π-(2π/3-x)】=4sinx+4sin(x+π/3)(拆开)=4sinx+4(sinxcosπ/3+cosxsinπ/3)=4sinx+4(1/2sinx+√3/2c
π/6+2kπ
原式=(sinx•(-sinx)•tanx)/(cosx•(-tanx)•cosx)=sin²x/cos²x=tan²x
得x=4kπ(k为整数)或x=4π/3+4kπ(k为整数).代入求得cos(x+π/3)的值为1/2或-1/2
令F’(x)=√3cos2x+sin2x=0,x1=kπ/2-π/6(k为偶数),x2=kπ/2-π/6(k为奇数)∴f(x)在x1极小,在x2处取极大值∴f(x)单调递减区间为[kπ/2-π/6,(
sin(x+π/3)sin(x+11π/6)=1/2则有:sin(x+π/3)sin[(x-π/6)+2π]=1/2sin(x+π/3)sin(x-π/6)=1/2-----(1)由于:sin(x+π
f(x)=sin(π-x)cos(2π-x)/sin(π/2+x)tan(π+x)=sinxcosx/cosxtanx=cosxf(31π/3)=cos(10π+π/3)=cosπ/3=1/2再问:它
f(x)=2√3sin(x/2+π/4)cos(x/2+π/4)-sin(x+π)=√3sin(x+π/2)+sinx=√3cosx+sinx=2sin(x+π/3),(1)2π.(2)g(x)=2s
f(x)=2sin2(π/6x)+sin(π/3x+π/6)-1=sin(π/3x+π/6)-[1-2sin2(π/6x)]=sin(π/3x+π/6)-cos(π/3x)=sin(π/3x)*cos