已知函数f(x)=2√3sinx×cosx+2cos²x-1(x∈R)
(1)解析:∵函数f(x)=2√3sinxcosx+2cos²x-1=√3sin2x+cos2x=2sin(2x+π\/6)∴f(x)的最小正周期为π f(0)=2sin(π\/6)=1,f(π\/2)=2sin(π+π\/6)=-1,f(π\/6)=2sin(π\/3+π\/6)=2 在区间[0,π\/2]上的最大值为2,最小值为-1 (2)解析:∵f(x0)=2s...
已知函数f(x)=2√3sinxcosx 2cos²x-1(x∈R)
f(x)=2√3sinxcosx +2cos²x-1 =√3sin2x+ 1+ cos2x-1 ==√3sin2x+cos2x =2sin(2x+π\/6)最小正周期=π x【0,π/2】 2x+π\/6【π\/6,7π\/6】最大值为2 最小值为0 2kπ+π\/2<2x+π\/6<2kπ+3π\/2 kπ+π\/6<x<kπ+2π\/3 ...
已知函数f(x)=2根号3sinxcosx+2cos方x-1(x属于R) 求函数f(x)的单调递...
f(x)=2√3sinxcosx+2cos²x-1=√3sin2x+cos2x=2sin(2x+π\/6),则递减区间是:2kπ+π\/2≤2x+π\/6≤2kπ+3π\/2,得:kπ+π\/6≤x≤kπ+2π\/3,则减区间是:[kπ+π\/6,kπ+2π\/3],其中k∈Z
已知函数f(x)=2√\/3sinx cosx+2cos²x—1(x∈R) (1)求函数f(x)的最...
已知函数f(x)=2√3 sinx cosx+2cos²x—1(x∈R)=√3sin2x +cos2x =2[(√3sin2x +cos2x)\/2]=2sin(2x+π\/3)2x=2π x=π 函数f(x)的最小正周期π x=0, f(x)=2sin(π\/3)= √3 x=兀\/2,2x+π\/3=π\/3 π\/3---2π+π\/3]函数f(x)最大值2,最小...
求解f(x)=2√3sinXcosX+2cos²X-1(X∈R),则f(x)的最小正周期是( )
f(x)=2√3sinXcosX+2cos²X-1 =√3sin(2X)+cos(2X)=2sin(2X+π\/6)T=(2π)\/2=π 答案:A
已知函数f(x)=2√3sinxcosx+2cos²x-1
f(x)=2√3sinxcosx+2cos²x-1 =√3sin2x+cos2x =2(√3\/2sin2x+1\/2cos2x)=2(sin2xcosπ\/6+cos2xsinπ\/6)=2sin(2x+π\/6)(1)对称轴:2x+π\/6=2kπ+π\/2 2x=2kπ+π\/3 x=kπ+π\/6;k∈Z 闭区间【0,π\/2】当x=π\/2时;函数有最小值=-2sin(π\/6)=-1 ...
f(x)=2根号3sinxcosx+2cos²x-1
解:f(x)=2√3sinxcosx+2cos²x-1 =√3sin(2x)+cos(2x)=2[(√3\/2)sin(2x)+(1\/2)cos(2x)]=2sin(2x+π\/6)x1∈[π\/4,π\/2]2π\/3≤2x1+π\/6≤7π\/6 cos(2x1+π\/6)<0 f(x1)=2sin(2x1+π\/6)=6\/5 sin(2x1+π\/6)=3\/5 cos(2x1+π\/6)=-√[1-...
已知函数f(x)=2根号3sinxcosx+2cos^2x-1,求f(x)的单调递减区间
f(x)=2√3sinxcosx+2cos²x-1 =√3sin2x+cos2x =2(√3\/2*sin2x+1\/2*cos2x)=2sin(2x+π\/6)由图像得:π\/2+2kπ≤2x+π\/6≤3π\/2+2kπ,k为整数 即π\/6+kπ≤x≤4π\/3+kπ,k为整数 则单调减区间为[π\/6+kπ,4π\/3+kπ],k为整数 ...
已知函数f(x)=2倍根号3sinxcosx+2cos²x-1(x∈R) (1)求函数的最小正...
先整理原式,f(x)=根号3sin2x+cos2x=2sin(2x+π\/6)(1)所以周期就是2π\/2=π (2)设y=cos2x,因为根号3sin2x+cos2x=6\/5,所以根号3sin2x=6\/5-cos2x 两边平方3(1-y*y)=36\/25+y*y-12y\/5整理的100y*y-60y-39=0 然后由于x∈[π\/4,π\/2],所以2x∈[π\/2,π],所以cos...
已知函数f《x》=2根号3sinxcosx+2cos²x-1《x属于R》.第一题,求fx...
解:由已知条件变形得:f(x)=√3sin2x+cos2x, x∈R.f(x)=2sin(2x+π\/6).∵x∈[0,π\/2], ∴2x+π\/6∈[π\/6,π+π\/6].∵f(x)在[0,π\/6]区间为增函数,在[π\/6,π\/2]区间为减函数,∴f(x)在x=π\/6处取得最大值2;∵f(π\/2)<f(0),∴f(x)在x=π\/2处,即...