求导函数:已知函数f(x)=2cos^2(3x-π/6)则函数f(x)在x=π/12处的导数fˊ(π/12)=?

问题描述:

求导函数:已知函数f(x)=2cos^2(3x-π/6)则函数f(x)在x=π/12处的导数fˊ(π/12)=?

先求导,fˊ(x)=-12cos(3x-π/6)sin(3x-π/6)=-6sin(6x-π/3)
带入数值:fˊ(π/12)=-6sin(π/2-π/3)=-3