(1)a·b=cos3/2xcosx/2-sin3/2xsinx/2=cos(1.5x+0.5x)=cos2x
|a+b|^2=a^2+2ab+b^2=1+2cos2x+1=2(1+cos2x)=4*(cosx)^2
x属于[0,π/2],所以|a+b|=2cosx
(2)f(x)=a·b-2m|a+b|=cos2x-2m*2cosx=2*(cosx)^2-4mcosx-1...
(1)a·b=cos3/2xcosx/2-sin3/2xsinx/2=cos(1.5x+0.5x)=cos2x
|a+b|^2=a^2+2ab+b^2=1+2cos2x+1=2(1+cos2x)=4*(cosx)^2
x属于[0,π/2],所以|a+b|=2cosx
(2)f(x)=a·b-2m|a+b|=cos2x-2m*2cosx=2*(cosx)^2-4mcosx-1...