Y=3sin(π 4-2X)的递增区间
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y=-1/2sin(2/3x-π/4)所以y和sin(2/3x-π/4)单调性相反sinx的增区间是(2kπ-π/2,2kπ+π/2)减区间是(2kπ+π/2,2kπ+3π/2)所以sin(2/3x-
x=0:0.01:1;y=0;fori=1:20y=y+sin(i*x);endplot(y);
y=sin(x+π/3)sin(x+π/2)=(sinx+√3cosx)cosx/2=[sinxcosx+√3(cosx)^2]/2=[sin2x/2+√3(cos2x+1)/2]/2=(sin2x+
x=-π/6时,y=0所以,关于点(-π/6,0)对称选B
对数函数底数小于1,为减函数,故g(x)=x^2+2x-3的单调减区间、且大于0为答案,即(负无穷,-3)再问:三角函数吧,这里没有对数函数的,再答:别为难我勒
sinx的对称轴是x=kπ+π/2只要令3x+π/4=kπ+π/2,解出的x即为该函数的对称轴,解出为π/12+k/3π这是解这类题目的套路:就是令括号里等于对称轴,解出相应的x
把两个三角函数展开,得y=3/2sinx-√3/2cosx合并成:y=√3sin(x-π/6)单调区间是(-π/3,2π/3)增(2π/3,5π/3)减其中都要加上2kπ,我就不写了
原式=(sinx/2+根号3cosx/2)cosx=sinxcosx/2+根号3cos^2x/2=sin2x/4+根号3cos2x/4+根号3/4=2sin(2x+π/3)+根号3/4T=2π/W=π
积化和差公式sinαsinβ=-1/2[cos(α+β)-cos(α-β)]令sinα=sin(x+π/3)sinβ=sin(x+π/2)话说到这一步了应该可以自己解决了吧这个高考不要求的吧!积化和差
y=6(2x+3)^2y=(e^x^2)2x-2y=cos(π/2x+4)×((-2π/(2x+4)^2))希望我写得清楚
2x+π/4=kπ+π/2x=kπ/2+π/8(k是整数)
∵函数表达式为y=3sin(2x+π4),∴ω=2,可得最小正周期T=|2πω|=|2π2|=π故答案为:π
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
sinx+siny+sinz-sin(x+y+z)=4sin[(x+y)/2]sin[(x+z)/2]sin[(y+z)/2]sinx+siny+sinz-sin(x+y+z)=2sin[(x+y)/
y'=2cos(2x-π/4)-3sin(3x+π/3)希望可以帮到你,如果解决了问题,请点下面的"选为满意回答"按钮,
令2kπ+π2≤3x+π4≤2kπ+3π2,k∈z,求得2kπ3+π12≤x≤2kπ3+7π36,故函数的减区间为[2kπ3+π12,2kπ3+7π36],k∈Z,故答案为:[2kπ3+π12,2kπ
y=1/2sin(π/4-2x/3)=-1/2sin(2x/3-π/4)不考虑周期时,根据正弦在[-π/2,π/2]递增,在[π/2,3π/2]递减结合本题前面有一个负号,则增减相反得单调递增区间([
y=2sin(2x+π/3)+sin(2x-π/3)=2(sin2xcos派/3+cos2xsin派/3)+sin2xcos派/3-cos2xsin派/3=3sin2xcos派/3+cos2xsin派
max:2x+π/4=2kπ+π/22x=2kπ+π/4x=kπ+π/8min:2x+π/4=2kπ-π/22x=2kπ-3π/4x=kπ-3π/8
y=sinx增区间[2kπ-π/2,2kπ+π/2]所以本题,2kπ-π/2≤π/4+2x≤2kπ+π/2kπ-3π/8