f(x)=cos(2兀-x)+cos(((8k+1)/2)π-x),
=cosx+cos(4kπ+π/2-x)
=cosx+sinx
=根号2 sin(x+π/4)
周期T=2π/1=2π.
减区间是:【2Kπ+π/2,2Kπ+3π/2】
f(x)在【0,π)上的减区间是【π/2,π)
f(x)=cos(2兀-x)+cos(((8k+1)/2)π-x),
=cosx+cos(4kπ+π/2-x)
=cosx+sinx
=根号2 sin(x+π/4)
周期T=2π/1=2π.
减区间是:【2Kπ+π/2,2Kπ+3π/2】
f(x)在【0,π)上的减区间是【π/2,π)