三角函数问题,在线等,速答速给分!!!
已知函数f(x)=sin^2wx+根号3coswx*cos(圆周率/2-wx)(w>0),且函数y=f(x)的图像相邻两条对称轴的距离为圆周率/2.(1)求f(圆周率/6...
已知函数f(x)=sin^2wx+根号3coswx*cos(圆周率/2-wx)(w>0),且函数y=f(x)的图像相邻两条对称轴的距离为圆周率/2.(1)求f(圆周率/6)的值。(2)若函数f(kx+圆周率/12)(k>0)在区间【-圆周率/6,圆周率/3】上单调递增,求k的取值范围。
展开
展开全部
f(x)=(sinwx)^2+√3.coswx.cos(π/2-wx)
=(sinwx)^2+√3.coswx.sinwx
=2sinwx(1/2.sinwx+√3/2coswx)
=2sinwx.sin(π/3+wx)
=cos(π/3)-cos(2wx+π/3)=0.5-cos(2wx+π/3);
周期T=2π/(2w)=π/w;
相邻两根对称轴的距离是T/2=π/2,所以T=π; 推得w=1;
即f(x)=0.5-cos(2x+π/3); 当x=π/6时,f(π/6)=1; (1)
f(kx+π/12)=0.5-cos(2kx+π/2)=0.5+sin2kx;
要使f(kx+π/12)递增,0<=2kx<=π/2; π/6<=x<=π/3; 推得k=[0, 3/4];
=(sinwx)^2+√3.coswx.sinwx
=2sinwx(1/2.sinwx+√3/2coswx)
=2sinwx.sin(π/3+wx)
=cos(π/3)-cos(2wx+π/3)=0.5-cos(2wx+π/3);
周期T=2π/(2w)=π/w;
相邻两根对称轴的距离是T/2=π/2,所以T=π; 推得w=1;
即f(x)=0.5-cos(2x+π/3); 当x=π/6时,f(π/6)=1; (1)
f(kx+π/12)=0.5-cos(2kx+π/2)=0.5+sin2kx;
要使f(kx+π/12)递增,0<=2kx<=π/2; π/6<=x<=π/3; 推得k=[0, 3/4];
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询