高校问答殖民地生存2d:三角求助
来源：百度文库 编辑：高校问答 时间：2024/04/30 00:03:44
将f(x)=3sin(x+pi/9)+5sin(x+4pi/9)
化成f(x)=Asin(x+B)形式
pi是圆周率3.14
化成f(x)=Asin(x+B)形式
pi是圆周率3.14
f(x)=3sin(x+π/9)+5sin(x+π/9+π/3)
=3sin(x+π/9)+5[sin(x+π/9)cosπ/3+cos(x+π/9)sinπ/3]
=11/2sin(x+π/9)+5*sqrt(3)/2cos(x+π/9)
=8[11/16sin(x+π/9)+5*sqrt(3)/16cos(x+π/9)]
(令sinα=5*sqrt(3)/16, cosα=11/16)
=8sin(x+π/9+α)