求函数fx=2sin²(四分之一π
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两倍角公式:sin2a=2sinacosa得2sinacosa=sin2acos2a=cos²a-sin²a=(1-sin²a)-sin²a=1-2sin
f(x)=√3sin²x+sinxcosx=√3[(1-cos2x)/2]+1/2sin2x=1/2sin2x-√3/2cos2x+√3/2=sin(2x-π/3)+√3/2∵x∈[π/2,
f(x)=cosx-cos(x+π/2)=cosx+sinx=3/4sin^2x+cos^2x+2sinxcosx=9/162sinxcosx=sin2x=9/16-1=-7/16
f到底是e的x^2次方还是x^2/e呢?我就按照后者计算了.首先,定义域(0,+∞)F(x)=x^2/e-2alnxF'=2x/e-2a/xa≤0时,F‘>0,F单调递增,无最值a>0时,F在(0,√
周期等于2派.g(x)=2sinx;基函数再问:有过程吗??再答:这可以看出来,还要过程吗,,,,周期等于2派/x前的数1===2派;;g(x)=2sint(x+pi/3+p1/3)=2sinx;si
1、最小正周期T=2π/2=π;最大值=2×1+2=4;2、单调递增式时-π/2+2kπ≤2x+π/3≤π/2+2kπ(k∈Z)-5π/6+2kπ≤2x≤π/6+2kπ(k∈Z)-5π/12+kπ≤x
f(x)=2sin(2x+π/3)最小正周期:2π/ω=2π/2=π最小值:f(x)=2*(-1)=-2最大值:f(x)=2*1=2当sin(2x+π/3)=-1时,取得最小值;2x+π/3=2kπ-
函数fx=2sin²x+sin2x-1=sin2x-cos2x=√2sin(2x-π/4)最大值=√2再问:�����ֵʱx��ȡֵ��ô��
sin(2x-π/4)>0且求sin(2x-π/4)的增区间即可2kπ
fx=4cos²x-2+1-cos²x-4cosx=3cos²x-4cosx-1令t=cosx则-1≤t≤1即求[3t²-4t-1]的最值
(1)f(x)=sin(2x+π/6)+3/2,最小正周期为2π/2=π,单增区间为2Kπ-π/2
fx=2cos²ωx+2sinωxcosωx+1=1+cos2ωx+sin2ωx+1=√2sin(2ωx+π/4)+2T=2π/ω,π/2=2π/2ω,ω=2f(x)=√2sin(x+π/4
f(x)=2sin(x-π/6)cosx+2cos²x=(2sinxcosπ/6-2cosxsinπ/6)cosx+2cos²x=√3sinxcosx-cos²x+2co
T=2π/2=π[-1,1]最大值为1,最小值为-1
第一题A.第二题B
解答;f(x)=sin(2x+3分之π)∴sin(2x+π/3)=-3/5∵x∈(0,π/2)∴2x+π/3∈(π/3,4π/3)∵sin(2x+π/3)
解1当2kπ-π/2≤2x+π/3≤2kπ+π/2,k属于Z时,y是增函数即2kπ-5π/6≤2x≤2kπ+π/6,k属于Z时,y是增函数即kπ-5π/12≤x≤kπ+π/12,k属于Z时,y是增函数
f(x)=sin(x/2)cos(x/2)+√3*sin²(x/2)+√3/2=1/2*sinx+√3/2*(1-cosx)+√3/2=1/2*sinx-√3/2*cosx+√3=sin(x
f(x)=√3sin2x-2sin²x=√3sin2x-(1-cos2x)=2sin(2x+π/6)-1∴当sin(2x+π/6)=1时f(x)max=2*1-1=1